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Santee City Council
September 24, 2025

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Ncil20250924
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September 24, 2025
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HAND AUGER
Rf (%)
0 1 2 3 4 5 6 7 8
Depth (ft)
5 0
4 8
4 6
4 4
4 2
4 0
3 8
3 6
3 4
3 2
3 0
2 8
2 6
2 4
2 2
2 0
1 8
1 6
1 4
1 2
1 0
8 6
4 2
0 Friction ratio Soil Behaviour Type

HAND AUGER
SBT (Robertson, 2010)
0 2 4 6 8 1 0 1 2 1 4 1 6 1 8
Depth (ft)
5 0
4 8
4 6
4 4
4 2
4 0
3 8
3 6
3 4
3 2
3 0
2 8
2 6
2 4
2 2
2 0
1 8
1 6
1 4
1 2
1 0
8 6
4 2
0 Soil Behaviour Type
Silty sand & sandy silt
Sand & silty sand
Silty sand & sandy silt
Sand & silty sand
Silty sand & sandy silt
Sand & silty sand
Sand & silty sand
Silty sand & sandy silt
Sand & silty sand
Sand & silty sand
Silty sand & sandy silt
Clay & silty clay
Clay & silty clay
Clay & silty clay
Clay
Sand
Sand & silty sand
Silty sand & sandy silt
Very dense/stiff soil
Very dense/stiff soil
Very dense/stiff soil
Very dense/stiff soil
Very dense/stiff soil
Silty sand & sandy silt
Very dense/stiff soil
Very dense/stiff soil
CPeT-IT v.2.3.1.9 - CPTU data presentation & interpretation software - Report created on: 4/25/2023, 12:47:27 PM 6 Project file: C:\CPT Project Data\Leighton-Santee4-23\CPT Report\CPeT.cpt

GREGG DRILLING & TESTING, INC.

GEOTECHNICAL AND ENVIRONMENTAL INVESTIGATION SERVICES
2726 Walnut Ave. • Signal Hill, California 90755 • (562) 427-6899 • FAX (562) 427-3314 www.greggdrilling.com
10/27/17
Leighton and Associates
Attn: Mike Jensen
Subject: CPT Site Investigation
City Ventures/Santee B
Santee, California
GREGG Project Number: 17-638SH
Dear Mr. Jensen:

The following report presents the results of GREGG Drilling & Testing’s Cone Penetration Test investigation for the above referenced site. The following testing services were performed:
1 Cone Penetration Tests (CPTU)
2 Pore Pressure Dissipation Tests (PPD)
3 Seismic Cone Penetration Tests (SCPTU)
4 UVOST Laser Induced Fluorescence (UVOST)
5 Groundwater Sampling (GWS)
6 Soil Sampling (SS)
7 Vapor Sampling (VS)
8 Pressuremeter Testing (PMT)
9 Vane Shear Testing (VST)
10 Dilatometer Testing (DMT)
A list of reference papers providing additional background on the specific tests conducted is provided in the bibliography following the text of the report. If you would like a copy of any of these publications or should you have any questions or comments regarding the contents of this report, please do not hesitate to contact our office at (562) 427-6899.

Sincerely,
GREGG Drilling & Testing, Inc.

Frank Stolfi
HRSC Division Manager, Gregg Drilling & Testing, Inc.

GREGG DRILLING & TESTING, INC.

GEOTECHNICAL AND ENVIRONMENTAL INVESTIGATION SERVICES
2726 Walnut Ave. • Signal Hill, California 90755 • (562) 427-6899 • FAX (562) 427-3314 www.greggdrilling.com
Cone Penetration Test Sounding Summary
-Table 1-
CPT Sounding
Identification
Date Termination
Depth (feet)
Depth of Groundwater
Samples (feet)
Depth of Soil
Samples (feet)
Depth of Pore
Pressure Dissipation
Tests (feet)
CPT-1 10/26/17 43 - - -
CPT-2 10/26/17 43 - - -
CPT-3 10/26/17 46 - - -
CPT-4 10/26/17 51 - - -
CPT-5 10/26/17 46 - - -
CPT-6 10/26/17 25 - - -
CPT-7 10/26/17 32 - - -
GREGG DRILLING & TESTING, INC.

GEOTECHNICAL AND ENVIRONMENTAL INVESTIGATION SERVICES
2726 Walnut Ave. • Signal Hill, California 90755 • (562) 427-6899 • FAX (562) 427-3314 www.greggdrilling.com
Bibliography
Lunne, T., Robertson, P.K. and Powell, J.J.M., “Cone Penetration Testing in Geotechnical Practice” E & FN Spon. ISBN 0 419 23750, 1997
Roberston, P.K., “Soil Classification using the Cone Penetration Test”, Canadian Geotechnical Journal, Vol. 27, 1990 pp. 151-158.

Mayne, P.W., “NHI (2002) Manual on Subsurface Investigations: Geotechnical Site Characterization”, available through www.ce.gatech.edu/~geosys/Faculty/Mayne/papers/index.html, Section 5.3, pp. 107-112.

Robertson, P.K., R.G. Campanella, D. Gillespie and A. Rice, “Seismic CPT to Measure In-Situ Shear Wave Velocity”, Journal of Geotechnical Engineering ASCE, Vol. 112, No. 8, 1986 pp. 791-803.

Robertson, P.K., Sully, J., Woeller, D.J., Lunne, T., Powell, J.J.M., and Gillespie, D.J., "Guidelines for Estimating Consolidation Parameters in Soils from Piezocone Tests", Canadian Geotechnical Journal, Vol. 29, No. 4, August 1992, pp. 539-550.

Robertson, P.K., T. Lunne and J.J.M. Powell, “Geo-Environmental Application of Penetration Testing”, Geotechnical Site Characterization, Robertson & Mayne (editors), 1998 Balkema, Rotterdam, ISBN 90 5410 939 4 pp 35-47.

Campanella, R.G. and I. Weemees, “Development and Use of An Electrical Resistivity Cone for Groundwater Contamination Studies”, Canadian Geotechnical Journal, Vol. 27 No. 5, 1990 pp. 557-567.

DeGroot, D.J. and A.J. Lutenegger, “Reliability of Soil Gas Sampling and Characterization Techniques”, International Site Characterization Conference - Atlanta, 1998.

Woeller, D.J., P.K. Robertson, T.J. Boyd and Dave Thomas, “Detection of Polyaromatic Hydrocarbon Contaminants Using the UVIF-CPT”, 53rd Canadian Geotechnical Conference Montreal, QC October pp. 733-739, 2000.

Zemo, D.A., T.A. Delfino, J.D. Gallinatti, V.A. Baker and L.R. Hilpert, “Field Comparison of Analytical Results from Discrete-Depth Groundwater Samplers” BAT EnviroProbe and QED HydroPunch, Sixth national Outdoor Action Conference, Las Vegas, Nevada Proceedings, 1992, pp 299-312.

Copies of ASTM Standards are available through www.astm.org Revised 02/05/2015   i
Cone Penetration Testing Procedure (CPT)
Gregg Drilling carries out all Cone Penetration Tests
(CPT) using an integrated electronic cone system,
Figure CPT.

The cone takes measurements of tip resistance (qc),
sleeve resistance (fs), and penetration pore water
pressure (u2). Measurements are taken at either 2.5 or
5 cm intervals during penetration to provide a nearly
continuous profile. CPT data reduction and basic
interpretation is performed in real time facilitating on‐ site decision making.   The above mentioned
parameters are stored electronically for further
analysis and reference.   All CPT soundings are
performed in accordance with revised ASTM standards
(D 5778‐12).

The 5mm thick porous plastic filter element is located
directly behind the cone tip in the u2 location.  A new saturated filter element is used on each sounding to
measure both penetration pore pressures as well as
measurements during a dissipation test (PPDT).  Prior
to each test, the filter element is fully saturated with oil under vacuum pressure to improve accuracy.

When the sounding is completed, the test hole is
backfilled according to client specifications.  If grouting is used, the procedure generally consists of pushing a
hollow tremie pipe with a “knock out” plug to the
termination depth of the CPT hole.   Grout is then
pumped under pressure as the tremie pipe is pulled
from the hole.  Disruption or further contamination to
the site is therefore minimized.

Figure CPT
Revised 02/05/2015   ii
Gregg 15cm2 Standard Cone Specifications
Dimensions
Cone base area   15 cm2
Sleeve surface area   225 cm2
Cone net area ratio 0.80
Specifications
Cone load cell
Full scale range   180 kN (20 tons)
Overload capacity 150%
Full scale tip stress 120 MPa (1,200 tsf)
Repeatability 120 kPa (1.2 tsf)
Sleeve load cell
Full scale range   31 kN (3.5 tons)
Overload capacity 150%
Full scale sleeve stress 1,400 kPa (15 tsf)
Repeatability 1.4 kPa (0.015 tsf)
Pore pressure transducer
Full scale range   7,000 kPa (1,000 psi)
Overload capacity 150%
Repeatability 7 kPa (1 psi)
Note: The repeatability during field use will depend somewhat on ground conditions, abrasion, maintenance and zero load stability.

Revised 2/05/2015   i
Cone Penetration Test Data & Interpretation
The Cone Penetration Test (CPT) data collected are presented in graphical and electronic form in the report.   The plots include interpreted Soil Behavior Type (SBT) based on the charts described by Robertson (1990).  Typical plots display SBT based on the non‐normalized charts of Robertson et al (1986).  For CPT soundings deeper than 30m, we recommend the use of the normalized charts of Robertson (1990) which can be displayed as SBTn, upon request.    The report also includes spreadsheet output of computer calculations of basic interpretation in terms of SBT and SBTn and various geotechnical parameters using current published correlations based on the comprehensive review by Lunne, Robertson and Powell (1997), as well as recent updates by Professor Robertson (Guide to Cone Penetration Testing, 2015). The interpretations are presented only as a guide for geotechnical use and should be carefully reviewed.  Gregg Drilling & Testing Inc. does not warranty the correctness or the applicability of any of the geotechnical parameters interpreted by the software and does not assume any liability for use of the results in any design or review. The user should be fully aware of the techniques and limitations of any method used in the software.  Some interpretation methods require input of the groundwater level to calculate vertical effective stress.

An estimate of the in‐situ groundwater level has been made based on field observations and/or CPT results, but should be verified by the user.

A summary of locations and depths is available in Table 1.   Note that all penetration depths referenced in the data are with respect to the existing ground surface.

Note that it is not always possible to clearly identify a soil type based solely on qt, fs, and u2.  In these situations, experience, judgment, and an assessment of the pore pressure dissipation data should be used to infer the correct soil behavior type.

Figure SBT (After Robertson et al., 1986) – Note: Colors may vary slightly compared to plots

ZONE SBT
1 2
3 4
5 6
7 8
9 10
11 12
Sensitive, fine grained
Organic materials
Clay
Silty clay to clay
Clayey silt to silty clay
Sandy silt to clayey silt
Silty sand to sandy silt
Sand to silty sand
Sand
Gravely sand to sand
Very stiff fine grained*
Sand to clayey sand*
*over consolidated or cemented
Revised 02/05/2015   i
Cone Penetration Test (CPT) Interpretation
Gregg uses a proprietary CPT interpretation and plotting software.  The software takes the CPT data and performs basic interpretation in terms of soil behavior type (SBT) and various geotechnical parameters using current published empirical correlations based on the comprehensive review by Lunne, Robertson and Powell (1997).  The interpretation is presented in tabular format using MS Excel. The interpretations are presented only as a guide for geotechnical use and should be carefully reviewed.  Gregg does not warranty the correctness or the applicability of any of the geotechnical parameters interpreted by the software and does not assume any liability for any use of the results in any design or review.  The user should be fully aware of the techniques and limitations of any method used in the software.

The following provides a summary of the methods used for the interpretation.  Many of the empirical correlations to estimate geotechnical parameters have constants that have a range of values depending on soil type, geologic origin and other factors.   The software uses ‘default’ values that have been selected to provide, in general, conservatively low estimates of the various geotechnical parameters.

Input:
1 Units for display (Imperial or metric) (atm. pressure, pa = 0.96 tsf or 0.1 MPa) 2 Depth interval to average results (ft or m).  Data are collected at either 0.02 or 0.05m and can be averaged every 1, 3 or 5 intervals.
3 Elevation of ground surface (ft or m)
4 Depth to water table, zw (ft or m) – input required
5 Net area ratio for cone, a (default to 0.80)
6 Relative Density constant, CDr (default to 350)
7 Young’s modulus number for sands, α (default to 5)
8 Small strain shear modulus number
a. for sands, SG (default to 180 for  SBTn  5, 6, 7)
b. for clays, CG (default to  50  for  SBTn 1, 2, 3 & 4) 9 Undrained shear strength cone factor for clays, Nkt (default to 15) 10 Over Consolidation ratio number, kocr (default to 0.3) 11 Unit weight of water, (default to γw = 62.4 lb/ft3 or 9.81 kN/m3 )
Column
1 Depth, z, (m) – CPT data is collected in meters
2 Depth (ft)
3 Cone resistance, qc (tsf or MPa)
4 Sleeve resistance, fs (tsf or MPa)
5 Penetration pore pressure, u (psi or MPa), measured behind the cone (i.e. u2) 6 Other – any additional data
7 Total cone resistance, qt (tsf or MPa)   qt = qc + u (1‐a) Revised 02/05/2015   ii
8 Friction Ratio, Rf (%)        Rf = (fs/qt) x 100%
9 Soil Behavior Type (non‐normalized), SBT   see note
10 Unit weight, γ (pcf or kN/m3
)     based on SBT, see note
11 Total overburden stress, σv (tsf)     σvo = σ z
12 In‐situ pore pressure, uo (tsf)     uo = γ w (z ‐ zw) 13 Effective overburden stress, σ'vo (tsf )   σ'vo = σvo ‐ uo 14 Normalized cone resistance, Qt1       Qt1= (qt ‐ σvo) / σ'vo 15 Normalized friction ratio, Fr (%)     Fr = fs / (qt ‐ σvo) x 100% 16 Normalized Pore Pressure ratio, Bq     Bq = u – uo / (qt ‐ σvo) 17 Soil Behavior Type (normalized), SBTn   see note
18 SBTn Index, Ic         see note
19 Normalized Cone resistance, Qtn (n varies with Ic)   see note 20 Estimated permeability, kSBT (cm/sec or ft/sec) see note 21 Equivalent SPT N60, blows/ft       see note
22 Equivalent SPT (N1)60 blows/ft     see note
23 Estimated Relative Density, Dr, (%)     see note
24 Estimated Friction Angle, φ', (degrees)   see note
25 Estimated Young’s modulus, Es (tsf)     see note
26 Estimated small strain Shear modulus, Go (tsf) see note 27 Estimated Undrained shear strength, su (tsf)   see note 28 Estimated Undrained strength ratio      su/σv’
29 Estimated Over Consolidation ratio, OCR   see note
Notes:
1 Soil Behavior Type (non‐normalized), SBT (Lunne et al., 1997 and table below) 2 Unit weight, γ either constant at 119 pcf or based on Non‐normalized SBT  (Lunne et al., 1997 and table below)
3 Soil Behavior Type (Normalized), SBTn   Lunne et al. (1997) 4 SBTn Index, Ic   Ic = ((3.47 – log Qt1)
2 + (log Fr + 1.22)2
)

0.5 5 Normalized Cone resistance, Qtn (n varies with Ic) Qtn = ((qt ‐ σvo)/pa) (pa/(σvo)
n  and recalculate Ic, then iterate:

When Ic < 1.64,      n = 0.5 (clean sand)
When Ic > 3.30,      n = 1.0 (clays)
When 1.64 < Ic < 3.30,   n = (Ic – 1.64)0.3 + 0.5
Iterate until the change in n, ∆n < 0.01
Revised 02/05/2015   iii
6 Estimated permeability, kSBT based on Normalized SBTn (Lunne et al., 1997 and table below) 7 Equivalent SPT N60, blows/ft   Lunne et al. (1997)
60 a
N
(qt /p ) = 8.5 

 

  4.6
I 1 c
8 Equivalent SPT (N1)60 blows/ft             (N1)60 = N60 CN, where CN = (pa/σvo)

0.5 9 Relative Density, Dr, (%)     Dr
2 = Qtn / CDr
Only SBTn 5, 6, 7 & 8     Show ‘N/A’ in zones 1, 2, 3, 4 & 9 10 Friction Angle, φ', (degrees) tan φ ' = 

 

  

 


0.29 '
q log 2.68
1 vo
c
Only SBTn 5, 6, 7 & 8   Show’N/A’ in zones 1, 2, 3, 4 & 9 11 Young’s modulus, Es       Es = α qt
Only SBTn 5, 6, 7 & 8   Show ‘N/A’ in zones 1, 2, 3, 4 & 9 12      Small strain shear modulus, Go
a. Go = SG (qt  σ'vo pa)1/3    For  SBTn 5, 6, 7
b. Go = CG qt   For  SBTn 1, 2, 3& 4
Show ‘N/A’ in zones 8 & 9
13 Undrained shear strength, su     su = (qt ‐ σvo) / Nkt Only SBTn 1, 2, 3, 4 & 9   Show ‘N/A’ in zones 5, 6, 7 & 8 14 Over Consolidation ratio, OCR   OCR = kocrQt1
Only SBTn 1, 2, 3, 4 & 9   Show ‘N/A’ in zones 5, 6, 7 & 8 The following updated and simplified SBT descriptions have been used in the software:

SBT Zones         SBTn Zones
1 sensitive fine grained   1   sensitive fine grained
2 organic soil       2   organic soil
3 clay        3 clay
4 clay & silty clay     4 clay & silty clay
5 clay & silty clay
6 sandy silt & clayey silt
Revised 02/05/2015   iv
7 silty sand & sandy silt   5 silty sand & sandy silt
8 sand & silty sand     6 sand & silty sand
9 sand
10 sand       7 sand
11 very dense/stiff soil*   8 very dense/stiff soil*
12 very dense/stiff soil*   9 very dense/stiff soil*
*heavily overconsolidated and/or cemented
Track when soils fall with zones of same description and print that description (i.e. if soils fall only within SBT zones 4 & 5, print ‘clays & silty clays’) Revised 02/05/2015   v
Estimated Permeability (see Lunne et al., 1997)
SBTn   Permeability (ft/sec)   (m/sec)

1   3x 10‐8       1x 10‐8

2   3x 10‐7       1x 10‐7

3   1x 10‐9       3x 10‐10
4   3x 10‐8       1x 10‐8

5   3x 10‐6       1x 10‐6

6   3x 10‐4       1x 10‐4

7   3x 10‐2       1x 10‐2

8     3x 10‐6       1x 10‐6

9   1x 10‐8       3x 10‐9

Estimated Unit Weight (see Lunne et al., 1997)
SBT   Approximate Unit Weight (lb/ft3
)   (kN/m3)
1   111.4         17.5
2      79.6         12.5
3   111.4         17.5
4   114.6         18.0
5   114.6         18.0
6   114.6         18.0
7   117.8         18.5
8   120.9         19.0
9   124.1         19.5
10   127.3         20.0
11   130.5         20.5
12   120.9         19.0

Revised 02.05.2015   i
Pore Pressure Dissipation Tests (PPDT)
Pore Pressure Dissipation Tests (PPDT’s) conducted at various intervals can be used to measure equilibrium water pressure (at the time of the CPT).  If conditions are hydrostatic, the equilibrium water pressure can be used to determine the approximate depth of the ground water table.   A PPDT is conducted when penetration is halted at specific intervals determined by the field representative.  The variation of the penetration pore pressure (u) with time is measured behind the tip of the cone and recorded.

Pore pressure dissipation data can be
interpreted to provide estimates of:
 Equilibrium piezometric pressure
 Phreatic Surface
 In situ horizontal coefficient of
consolidation (ch)
 In situ horizontal coefficient of
permeability (kh)
In order to correctly interpret the
equilibrium piezometric pressure and/or the
phreatic surface, the pore pressure must be
monitored until it reaches equilibrium,
Figure PPDT.  This time is commonly referred
to as t100, the point at which 100% of the
excess pore pressure has dissipated.

A complete reference on pore pressure
dissipation tests is presented by Robertson
et al. 1992 and Lunne et al. 1997.

A summary of the pore pressure dissipation
tests are summarized in Table 1.

Figure PPDT
Revised 02/05/2015   i
Seismic Cone Penetration Testing (SCPT)
Seismic Cone Penetration Testing (SCPT) can be conducted at various intervals during the Cone Penetration Test.  Shear wave velocity (Vs) can then be calculated over a specified interval with depth. A small interval forseismic testing,such as 1‐1.5m (3‐5ft) allowsfor a detailed look at the shear wave profile with depth. Conversely, a larger interval such as 3‐6m (10‐20ft) allows for a more average shear wave velocity to be calculated. Gregg’s cones have a horizontally active geophone located 0.2m (0.66ft) behind the tip.

To conduct the seismic shear wave test, the penetration of the cone isstopped and the rods are decoupled from the rig.  An automatic hammer is triggered to send a shear wave into the soil. The distance from the source to the cone is calculated knowing the total depth of the cone and the horizontal offset distance between the source and the cone.  To calculate an interval velocity, a minimum of two tests must be performed at two different
depths. The arrival times
between the two wave traces
are compared to obtain the
difference in time (∆t). The
difference in depth is
calculated (∆d) and velocity
can be determined using the
simple equation: v = ∆d/∆t
Multiple wave traces can be
recorded at the same depth
to improve quality of the
data.

A complete reference on
seismic cone penetration
tests is presented by
Robertson et al. 1986 and
Lunne et al. 1997.

A summary the shear wave
velocities, arrival times and
wave traces are provided
with the report.

Figure SCPT
(S)
1 2
t 1
2 12
2 1
2 1
Revised 3/09/2015   i
Groundwater Sampling
Gregg Drilling & Testing, Inc. conducts groundwater
sampling using a sampler as shown in Figure GWS.

The groundwatersampler has a retrievable stainless
steel or disposable PVC screen with steel drop off
tip. This allows for samples to be taken at multiple
depth intervals within the same sounding location.

In areas of slower water recharge, provisions may
be made to set temporary PVC well screens during
sampling to allow the pushing equipment to
advance to the next sample location while the
groundwater is allowed to infiltrate.

The groundwater sampler operates by advancing

44.5mm (1¾ inch) hollow push rods with the filter
tip in a closed configuration to the base of the
desired sampling interval. Once at the desired
sample depth, the push rods are retracted; exposing
the encased filter screen and allowing groundwater
to infiltrate hydrostatically from the formation into
the inlet screen. A small diameter bailer
(approximately ½ or ¾ inch) is lowered through the
push rods into the screen section for sample
collection. The number of downhole trips with the
bailer and time necessary to complete the sample
collection at each depth interval is a function of
sampling protocols, volume requirements, and the
yield characteristics and storage capacity of the
formation. Upon completion of sample collection,
the push rods and sampler, with the exception of
the PVC screen and steel drop off tip are retrieved
to the ground surface, decontaminated and
prepared for the next sampling event.

For a detailed reference on direct push groundwater
sampling, refer to Zemo et. al., 1992. Figure GWS
Revised 02/05/2015   i
Soil Sampling
Gregg Drilling & Testing, Inc. uses a piston‐type
push‐in sampler to obtain small soil samples
without generating any soil cuttings, Figure SS.

Two different types of samplers (12 and 18 inch)
are used depending on the soil type and density.

The soil sampler is initially pushed in a "closed"
position to the desired sampling interval using
the CPT pushing equipment. Keeping the sampler
closed minimizes the potential of cross
contamination. The inner tip of the sampler is
then retracted leaving a hollow soil sampler with
inner 1¼” diameter sample tubes. The hollow
sampler is then pushed in a locked "open"
position to collect a soil sample. The filled
sampler and push rods are then retrieved to the
ground surface. Because the soil enters the
sampler at a constant rate, the opportunity for
100% recovery is increased. For environmental
analysis, the soil sample tube ends are sealed
with Teflon and plastic caps. Often, a longer "split
tube" can be used for geotechnical sampling.

For a detailed reference on direct push soil
sampling, refer to Robertson et al, 1998.

Figure SS

PREVIOUS BORING LOGS
Law Crandall, 1999

APPENDIX C
Laboratory Testing Procedures & Results
Preliminary Geotechnical Investigation Project No. 11832.002 Santee 3 Residential Development May 19, 2023
C-1

APPENDIX C
Laboratory Testing Procedures and Test Results
Expansion Index Tests: The expansion index of selected materials was evaluated in general accordance with ASTM D 4829. A specimens was molded under a specified compactive energy at approximately 50 percent saturation (plus or minus 1 percent). The prepared 1-inch thick by 4-inch diameter specimen was loaded with a surcharge of 144 pounds per square foot and were inundated with tap water. Readings of volumetric swell were made for a period of 24 hours. The results are presented in the table below.

Minimum Resistivity and pH Tests: Minimum resistivity and pH tests were performed in general accordance with Caltrans Test Method CT643. The results are presented in the table below:

Sample
Location Sample Description pH
Minimum
Resistivity (ohmscm)
CPT-9 @ 1-4’ Silty Sand, Light Brown 7.02 12,100
CPT-13 @ 1-4’ Silty Sand, Light Brown 7.11 12,200
Chloride Content: Chloride content was tested in accordance with Caltrans Test Method CT422. The results are presented below:

Sample Location Sample Description Chloride Content, ppm CPT-9 @ 1-4’ Silty Sand, Light Brown 10
CPT-13 @ 1-4’ Silty Sand, Light Brown 10
Sample Location Sample Description Expansion
Index
Expansion
Potential
CPT-9 @ 1 to 5 feet Brown Silty SAND 0 Very Low
Preliminary Geotechnical Investigation Project No. 11832.002 Santee 3 Residential Development May 19, 2023
C-2
APPENDIX C (Continued)
Soluble Sulfates: The soluble sulfate contents of selected samples were determined by standard geochemical methods (Caltrans Test Method CT417). The test results are presented in the table below:

Sample Location Sample Description
Sulfate
Content
(ppm)
Potential
Degree of
Sulfate
Attack*
CPT-9 @ 1-4’ Silty Sand, Light Brown < 150 Not
Applicable
CPT-13 @ 1-4’ Silty Sand, Light Brown < 150 Not
Applicable
* Based on the 2019 edition of American Concrete Institute (ACI) Committee 318R, Table No. 4.2.1.

APPENDIX D
Liquefaction Analysis
Leighton
San Diego, CA
Overall vertical settlements report
Project title : City Ventures Santee 3
Location : Santee, California
CPTu Name
CPT-01
CPT-02CPT-03CPT-04CPT-05CPT-06CPT-07
CPT-8CPT-9
CPT-10CPT-11CPT-12CPT-13
Vertical settlement (in)

7.50 7.00

6.50 6.00

5.50 5.00

4.50 4.00

3.50 3.00

2.50 2.00

1.50 1.00

0.50 0.00

1.342

5.506

4.076 3.935

5.191

1.683

0.877

7.058

3.52 4.582

3.247

4.914

4.381
CLiq v.3.0.3.4 - CPT Liquefaction Assessment Software 1 Project file: \\ds-sd\project\`InFocus PROJECTS\11502-12001\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Cliq\City Ventures Santee 3_cetin.clq Leighton
San Diego, CA
Overall lateral displacements report
Project title : City Ventures Santee 3Location : Santee, California CPTu Name
CPT-01
CPT-02
CPT-03
CPT-04
CPT-05
CPT-06
CPT-07
CPT-8
CPT-9
CPT-10
CPT-11
CPT-12
CPT-13
Lateral displacement (in)

32.0031.0030.0029.0028.0027.0026.0025.0024.0023.0022.0021.0020.0019.0018.0017.0016.0015.0014.0013.0012.0011.0010.00

9.008.007.006.005.004.003.002.001.000.00
0 23.477

26.026

19.262

14.477
0 0 0

10.552

27.613

12.838

29.587

25.738
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software 1Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-01

15.00 ft

15.00 ft
3 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

Yes

3.00 ft
120.00 lb/ft3
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
4321
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 SBTn Plot CRR plot
FILL

HAND AUGER

CRR & CSR
0 0.2 0.4 0.6
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio HAND AUGER
Rf (%)
86420 10
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot

HAND AUGER
FILL
Factor of safety
0 0.5 1 1.5 2
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:54 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 1 This software is licensed to: Leighton Group, Inc CPT name: CPT-01 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
43424140393837363534333231302928272625242322212019181716151413121110 98765
Cone resistance
CPT basic interpretation plots
Friction Ratio HAND AUGER
Rf (%)
86420 10
Depth (ft)
43424140393837363534333231302928272625242322212019181716151413121110 98765
Friction Ratio Pore pressure HAND AUGER
u (psi)
0 50 100
Depth (ft)
43424140393837363534333231302928272625242322212019181716151413121110 98765
Pore pressure
Insitu
SBT Plot HAND AUGER
Ic(SBT)
1 2 3 4
Depth (ft)
43424140393837363534333231302928272625242322212019181716151413121110 98765
SBT Plot Soil Behaviour Type

HAND AUGER
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
4240383634323028262422201816141210
86420
Soil Behaviour Type
Silty sand & sandy siltSilty sand & sandy siltSand & silty sandSilty sand & sandy siltClay & silty claySilty sand & sandy siltVery dense/stif f soilVery dense/stif f soilClay & silty clayClay & silty clayClay & silty clayVery dense/stif f soilClayClayClay & silty clayVery dense/stif f soilVery dense/stif f soilSand & silty sandVery dense/stif f soilSand & silty sandSand CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:54 AM 2Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4215.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

15.00 ft32.60Based on SBT
Yes

3.00 ft
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:
120.00 lb/ft3
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-01 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
43424140393837363534333231302928272625242322212019181716151413121110 98765
Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
43424140393837363534333231302928272625242322212019181716151413121110 98765
SBTn Plot FS Plot

HAND AUGER
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
4240383634323028262422201816141210
86420
FS Plot
During earthq.

Vertical settlements
FILL

HAND AUGER
Settlement (in)
0 0.5 1
Depth (ft)
4240383634323028262422201816141210
86420
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
FILL
Volumentric strain (%)
6543210
Depth (ft)
4240383634323028262422201816141210
86420
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:54 AM 3Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-02

19.00 ft

19.00 ft
3 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

Yes

3.00 ft
120.00 lb/ft3
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
500
Depth (ft)
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
Cone resistance SBTn Plot
Ic (Robertson 1990)
4321
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
SBTn Plot CRR plot
FILL

CRR & CSR
0 0.2 0.4 0.6
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio
Rf (%)
86420 10
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:55 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 4 This software is licensed to: Leighton Group, Inc CPT name: CPT-02 Cone resistance
qt (tsf)
200 400 600
Depth (ft)
4240383634323028262422201816141210
86420
Cone resistance
CPT basic interpretation plots
Friction Ratio
Rf (%)
86420 10
Depth (ft)
4240383634323028262422201816141210
86420
Friction Ratio Pore pressure
u (psi)
0 10 20 30
Depth (ft)
4240383634323028262422201816141210
86420
Pore pressure
Insitu
SBT Plot
Ic(SBT)
1 2 3 4
Depth (ft)
4240383634323028262422201816141210
86420
SBT Plot Soil Behaviour Type
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
4240383634323028262422201816141210
86420
Soil Behaviour Type
Silty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy silt CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:55 AM 5Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4219.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

19.00 ft32.60Based on SBT
Yes

3.00 ft
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:
120.00 lb/ft3
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-02 Cone resistance
qt (tsf)
200 400 600
Depth (ft)
4240383634323028262422201816141210
86420
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
4240383634323028262422201816141210
86420
SBTn Plot FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
4240383634323028262422201816141210
86420
FS Plot
During earthq.

Vertical settlements
FILL
Settlement (in)
543210
Depth (ft)
4240383634323028262422201816141210
86420
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
FILL
Volumentric strain (%)
6543210
Depth (ft)
4240383634323028262422201816141210
86420
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:55 AM 6Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain This software is licensed to: Leighton Group, Inc CPT name: CPT-02 Cone resistance
qt (tsf)
200 400 600
Depth (ft)
4240383634323028262422201816141210
86420
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
4240383634323028262422201816141210
86420
SBTn Plot Corrected norm. cone resista
Qtn,cs
0 10050 150 200
Depth (ft)
4240383634323028262422201816141210
86420
Corrected norm. cone resista FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
4240383634323028262422201816141210
86420
FS Plot
During earthq.

Cyclic shear strain
FILL
Gamma max (%)
0 2010 30 40 50 60
Depth (ft)
4240383634323028262422201816141210
86420
Cyclic shear strain Lateral displacements
FILL
Displacement (in)
0 10 20
Depth (ft)
4240383634323028262422201816141210
86420
Lateral displacements
Estimation of post-earthquake lateral Displacements
Geometric parameters: Level ground (or gently sloping) with free face (L: 700.00 ft - H: 16.00 ft) CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:55 AM 7 Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq qt: Total cone resistance (cone resistance qc corrected for pore water effects) Ic: Soil Behaviour Type Index
Qtn,cs: Equivalent clean sand normalized CPT total cone resistance F.S.: Factor of safetyγmax: Maximum cyclic shear strain LDI: Lateral displacement index
Abbreviations Surface condition

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-03

15.00 ft

15.00 ft
3 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

Yes

3.00 ft
120.00 lb/ft3
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
500
Depth (ft)
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 Cone resistance SBTn Plot
Ic (Robertson 1990)
4321
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 SBTn Plot CRR plot
FILL

CRR & CSR
0 0.2 0.4 0.6
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio
Rf (%)
86420 10
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:56 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 8 This software is licensed to: Leighton Group, Inc CPT name: CPT-03 Cone resistance
qt (tsf)
200 400 600 800
Depth (ft)
444240383634323028262422201816141210
86420
Cone resistance
CPT basic interpretation plots
Friction Ratio
Rf (%)
86420 10
Depth (ft)
444240383634323028262422201816141210
86420
Friction Ratio Pore pressure
u (psi)
0 20 40 60 80
Depth (ft)
444240383634323028262422201816141210
86420
Pore pressure
Insitu
SBT Plot
Ic(SBT)
1 2 3 4
Depth (ft)
444240383634323028262422201816141210
86420
SBT Plot Soil Behaviour Type
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
444240383634323028262422201816141210
86420
Soil Behaviour Type
Silty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSand & silty sandSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSandSand & silty sandSandSand & silty sandSand CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:56 AM 9Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4215.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

15.00 ft32.60Based on SBT
Yes

3.00 ft
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:
120.00 lb/ft3
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-03 Cone resistance
qt (tsf)
200 400 600 800
Depth (ft)
444240383634323028262422201816141210
86420
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
444240383634323028262422201816141210
86420
SBTn Plot FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
444240383634323028262422201816141210
86420
FS Plot
During earthq.

Vertical settlements
FILL
Settlement (in)
43210
Depth (ft)
444240383634323028262422201816141210
86420
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
FILL
Volumentric strain (%)
6543210
Depth (ft)
444240383634323028262422201816141210
86420
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:56 AM 10Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain This software is licensed to: Leighton Group, Inc CPT name: CPT-03 Cone resistance
qt (tsf)
200 600400 800
Depth (ft)
444240383634323028262422201816141210
86420
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
444240383634323028262422201816141210
86420
SBTn Plot Corrected norm. cone resista
Qtn,cs
0 10050 150 200
Depth (ft)
444240383634323028262422201816141210
86420
Corrected norm. cone resista FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
444240383634323028262422201816141210
86420
FS Plot
During earthq.

Cyclic shear strain
FILL
Gamma max (%)
0 2010 30 40 50 60
Depth (ft)
444240383634323028262422201816141210
86420
Cyclic shear strain Lateral displacements
FILL
Displacement (in)
0 10 20
Depth (ft)
444240383634323028262422201816141210
86420
Lateral displacements
Estimation of post-earthquake lateral Displacements
Geometric parameters: Level ground (or gently sloping) with free face (L: 350.00 ft - H: 16.00 ft) CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:56 AM 11 Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq qt: Total cone resistance (cone resistance qc corrected for pore water effects) Ic: Soil Behaviour Type Index
Qtn,cs: Equivalent clean sand normalized CPT total cone resistance F.S.: Factor of safetyγmax: Maximum cyclic shear strain LDI: Lateral displacement index
Abbreviations Surface condition

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-04

13.00 ft

13.00 ft
3 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

Yes

3.00 ft
120.00 lb/ft3
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
0 500
Depth (ft)
52 50
48 46
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 Cone resistance SBTn Plot
Ic (Robertson 1990)
4321
52 50
48 46
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 SBTn Plot CRR plot
FILL

CRR & CSR
0 0.2 0.4 0.6
52 50
48 46
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio
Rf (%)
86420 10
52 50
48 46
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
52 50
48 46
44 42
40 38
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:56 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 12 This software is licensed to: Leighton Group, Inc CPT name: CPT-04 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
52504846444240383634323028262422201816141210
86420
Cone resistance
CPT basic interpretation plots
Friction Ratio
Rf (%)
86420 10
Depth (ft)
52504846444240383634323028262422201816141210
86420
Friction Ratio Pore pressure
u (psi)
0 20 40 60
Depth (ft)
52504846444240383634323028262422201816141210
86420
Pore pressure
Insitu
SBT Plot
Ic(SBT)
1 2 3 4
Depth (ft)
52504846444240383634323028262422201816141210
86420
SBT Plot Soil Behaviour Type
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
52504846444240383634323028262422201816141210
86420
Soil Behaviour Type
Sensitiv e f ine grainedSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSilty sand & sandy siltVery dense/stif f soilVery dense/stif f soil CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:56 AM 13Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4213.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

13.00 ft32.60Based on SBT
Yes

3.00 ft
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:
120.00 lb/ft3
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-04 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
52504846444240383634323028262422201816141210
86420
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
52504846444240383634323028262422201816141210
86420
SBTn Plot FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
52504846444240383634323028262422201816141210
86420
FS Plot
During earthq.

Vertical settlements
FILL
Settlement (in)
3210 4
Depth (ft)
52504846444240383634323028262422201816141210
86420
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
FILL
Volumentric strain (%)
6543210
Depth (ft)
52504846444240383634323028262422201816141210
86420
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:56 AM 14Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain This software is licensed to: Leighton Group, Inc CPT name: CPT-04 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
52504846444240383634323028262422201816141210
86420
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
52504846444240383634323028262422201816141210
86420
SBTn Plot Corrected norm. cone resista
Qtn,cs
0 10050 150 200
Depth (ft)
52504846444240383634323028262422201816141210
86420
Corrected norm. cone resista FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
52504846444240383634323028262422201816141210
86420
FS Plot
During earthq.

Cyclic shear strain
FILL
Gamma max (%)
0 2010 30 40 50 60
Depth (ft)
52504846444240383634323028262422201816141210
86420
Cyclic shear strain Lateral displacements
FILL
Displacement (in)
50 1510
Depth (ft)
52504846444240383634323028262422201816141210
86420
Lateral displacements
Estimation of post-earthquake lateral Displacements
Geometric parameters: Level ground (or gently sloping) with free face (L: 300.00 ft - H: 14.00 ft) CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:56 AM 15 Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq qt: Total cone resistance (cone resistance qc corrected for pore water effects) Ic: Soil Behaviour Type Index
Qtn,cs: Equivalent clean sand normalized CPT total cone resistance F.S.: Factor of safetyγmax: Maximum cyclic shear strain LDI: Lateral displacement index
Abbreviations Surface condition

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-05

15.00 ft

15.00 ft
3 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

Yes

3.00 ft
120.00 lb/ft3
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
500
Depth (ft)
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
Cone resistance SBTn Plot
Ic (Robertson 1990)
4321
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
SBTn Plot CRR plot
FILL

CRR & CSR
0 0.2 0.4 0.6
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio
Rf (%)
86420 10
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:57 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 16 This software is licensed to: Leighton Group, Inc CPT name: CPT-05 Cone resistance
qt (tsf)
200 400 600
Depth (ft)
46444240383634323028262422201816141210
86420
Cone resistance
CPT basic interpretation plots
Friction Ratio
Rf (%)
86420 10
Depth (ft)
46444240383634323028262422201816141210
86420
Friction Ratio Pore pressure
u (psi)
0 10 20 30
Depth (ft)
46444240383634323028262422201816141210
86420
Pore pressure
Insitu
SBT Plot
Ic(SBT)
1 2 3 4
Depth (ft)
46444240383634323028262422201816141210
86420
SBT Plot Soil Behaviour Type
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
46444240383634323028262422201816141210
86420
Soil Behaviour Type
Silty sand & sandy siltSand & silty sandSand & silty sandSilty sand & sandy siltSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSilty sand & sandy siltSilty sand & sandy siltSand & silty sandSand & silty sand CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:57 AM 17Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4215.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

15.00 ft32.60Based on SBT
Yes

3.00 ft
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:
120.00 lb/ft3
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-05 Cone resistance
qt (tsf)
200 400 600
Depth (ft)
46444240383634323028262422201816141210
86420
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
46444240383634323028262422201816141210
86420
SBTn Plot FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
46444240383634323028262422201816141210
86420
FS Plot
During earthq.

Vertical settlements
FILL
Settlement (in)
543210
Depth (ft)
46444240383634323028262422201816141210
86420
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
FILL
Volumentric strain (%)
6543210
Depth (ft)
46444240383634323028262422201816141210
86420
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:57 AM 18Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain This software is licensed to: Leighton Group, Inc CPT name: CPT-05 Cone resistance
qt (tsf)
200 400 600
Depth (ft)
46444240383634323028262422201816141210
86420
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
46444240383634323028262422201816141210
86420
SBTn Plot Corrected norm. cone resista
Qtn,cs
0 10050 150 200
Depth (ft)
46444240383634323028262422201816141210
86420
Corrected norm. cone resista FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
46444240383634323028262422201816141210
86420
FS Plot
During earthq.

Cyclic shear strain
FILL
Gamma max (%)
0 2010 30 40 50 60
Depth (ft)
46444240383634323028262422201816141210
86420
Cyclic shear strain Lateral displacements
FILL
Displacement (in)
0 5 10
Depth (ft)
46444240383634323028262422201816141210
86420
Lateral displacements
Estimation of post-earthquake lateral Displacements
Geometric parameters: Level ground (or gently sloping) with free face (L: 800.00 ft - H: 16.00 ft) CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:57 AM 19 Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq qt: Total cone resistance (cone resistance qc corrected for pore water effects) Ic: Soil Behaviour Type Index
Qtn,cs: Equivalent clean sand normalized CPT total cone resistance F.S.: Factor of safetyγmax: Maximum cyclic shear strain LDI: Lateral displacement index
Abbreviations Surface condition

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-06

13.00 ft

13.00 ft
3 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

Yes

3.00 ft
120.00 lb/ft3
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
200 400 600
Depth (ft)
25 24
23 22
21 20
19 18
17 16
15 14
13 12
11 10
9 8
7 6
5 4
3 2
1 Cone resistance SBTn Plot
Ic (Robertson 1990)
4321
25 24
23 22
21 20
19 18
17 16
15 14
13 12
11 10
9 8
7 6
5 4
3 2
1 SBTn Plot CRR plot
FILL

CRR & CSR
0 0.2 0.4 0.6
25 24
23 22
21 20
19 18
17 16
15 14
13 12
11 10
9 8
7 6
5 4
3 2
1 CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio
Rf (%)
86420 10
25 24
23 22
21 20
19 18
17 16
15 14
13 12
11 10
9 8
7 6
5 4
3 2
1 Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
25 24
23 22
21 20
19 18
17 16
15 14
13 12
11 10
9 8
7 6
5 4
3 2
1 FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:58 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 20 This software is licensed to: Leighton Group, Inc CPT name: CPT-06 Cone resistance
qt (tsf)
200 400 600
Depth (ft)
25242322212019181716151413121110
987654321
Cone resistance
CPT basic interpretation plots
Friction Ratio
Rf (%)
86420 10
Depth (ft)
25242322212019181716151413121110
987654321
Friction Ratio Pore pressure
u (psi)
0 100 200
Depth (ft)
25242322212019181716151413121110
987654321
Pore pressure
Insitu
SBT Plot
Ic(SBT)
1 2 3 4
Depth (ft)
25242322212019181716151413121110
987654321
SBT Plot Soil Behaviour Type
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
25242322212019181716151413121110
9876543210
Soil Behaviour Type
Sand & silty sandSilty sand & sandy siltClay & silty claySilty sand & sandy siltClay & silty claySand & silty sandVery dense/stif f soilVery dense/stif f soil CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:58 AM 21Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4213.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

13.00 ft32.60Based on SBT
Yes

3.00 ft
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:
120.00 lb/ft3
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-06 Cone resistance
qt (tsf)
200 400 600
Depth (ft)
25242322212019181716151413121110
987654321
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
25242322212019181716151413121110
987654321
SBTn Plot FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
25242322212019181716151413121110
987654321
FS Plot
During earthq.

Vertical settlements
FILL
Settlement (in)
0 0.5 1 1.5
Depth (ft)
25242322212019181716151413121110
987654321
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
FILL
Volumentric strain (%)
6543210
Depth (ft)
25242322212019181716151413121110
987654321
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:58 AM 22Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-07

14.00 ft

14.00 ft
3 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

Yes

3.00 ft
120.00 lb/ft3
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
0 500
Depth (ft)
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
Cone resistance SBTn Plot
Ic (Robertson 1990)
4321
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
SBTn Plot CRR plot
FILL

CRR & CSR
0 0.2 0.4 0.6
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio
Rf (%)
86420 10
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:58 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 23 This software is licensed to: Leighton Group, Inc CPT name: CPT-07 Cone resistance
qt (tsf)
0 200 400 600 800
Depth (ft)
31302928272625242322212019181716151413121110
987654321
Cone resistance
CPT basic interpretation plots
Friction Ratio
Rf (%)
86420 10
Depth (ft)
31302928272625242322212019181716151413121110
987654321
Friction Ratio Pore pressure
u (psi)
0 5 10
Depth (ft)
31302928272625242322212019181716151413121110
987654321
Pore pressure
Insitu
SBT Plot
Ic(SBT)
1 2 3 4
Depth (ft)
31302928272625242322212019181716151413121110
987654321
SBT Plot Soil Behaviour Type
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
31302928272625242322212019181716151413121110
9876543210
Soil Behaviour Type
Sand & silty sandSand & silty sandSilty sand & sandy siltClay & silty clayClayClay & silty claySilty sand & sandy siltClay & silty claySilty sand & sandy siltSilty sand & sandy siltVery dense/stif f soilSilty sand & sandy siltClay & silty claySilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sand CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:58 AM 24Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4214.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

14.00 ft32.60Based on SBT
Yes

3.00 ft
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:
120.00 lb/ft3
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-07 Cone resistance
qt (tsf)
200 400 600 800
Depth (ft)
31302928272625242322212019181716151413121110
987654321
Cone resistance SBTn Plot
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
31302928272625242322212019181716151413121110
987654321
SBTn Plot FS Plot
FILL
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
31302928272625242322212019181716151413121110
987654321
FS Plot
During earthq.

Vertical settlements
FILL
Settlement (in)
0 0.2 0.4 0.6 0.8
Depth (ft)
31302928272625242322212019181716151413121110
987654321
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
FILL
Volumentric strain (%)
6543210
Depth (ft)
31302928272625242322212019181716151413121110
987654321
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:58 AM 25Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-8

13.00 ft

13.00 ft
1 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

No
N/A
N/A
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
4321
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 SBTn Plot CRR plot

HAND AUGER

CRR & CSR
0 0.2 0.4 0.6
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio HAND AUGER
Rf (%)
86420 10
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:59 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 26 This software is licensed to: Leighton Group, Inc CPT name: CPT-8 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
46454443424140393837363534333231302928272625242322212019181716151413121110 98765
Cone resistance
CPT basic interpretation plots
Friction Ratio HAND AUGER
Rf (%)
86420 10
Depth (ft)
454443424140393837363534333231302928272625242322212019181716151413121110 98765
Friction Ratio Pore pressure HAND AUGER
u (psi)
50 10
Depth (ft)
46454443424140393837363534333231302928272625242322212019181716151413121110 98765
Pore pressure
Insitu
SBT Plot HAND AUGER
Ic(SBT)
1 2 3 4
Depth (ft)
454443424140393837363534333231302928272625242322212019181716151413121110 98765
SBT Plot Soil Behaviour Type

HAND AUGER
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
46444240383634323028262422201816141210
86420
Soil Behaviour Type
Silty sand & sandy siltSand & silty sandSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSand & silty sandSand & silty sandSilty sand & sandy siltSilty sand & sandy siltClayClay & silty claySand & silty sandSand & silty sandSand & silty sandSand & silty sandSand CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:59 AM 27Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4213.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

13.00 ft12.60Based on SBTNoN/A
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:

N/A
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-8 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
46454443424140393837363534333231302928272625242322212019181716151413121110 98765
Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
454443424140393837363534333231302928272625242322212019181716151413121110 98765
SBTn Plot FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
46444240383634323028262422201816141210
86420
FS Plot
During earthq.

Vertical settlements

HAND AUGER
Settlement (in)
0 2 4 6
Depth (ft)
46444240383634323028262422201816141210
86420
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
Volumentric strain (%)
6543210
Depth (ft)
46444240383634323028262422201816141210
86420
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:34:59 AM 28Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-9

13.00 ft

13.00 ft
1 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

No
N/A
N/A
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
0 200 400
Depth (ft)
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
4321
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 SBTn Plot CRR plot

HAND AUGER

CRR & CSR
0 0.2 0.4 0.6
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio HAND AUGER
Rf (%)
86420 10
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:00 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 29 This software is licensed to: Leighton Group, Inc CPT name: CPT-9 Cone resistance
qt (tsf)
0 200 400
Depth (ft)
46444240383634323028262422201816141210
86 Cone resistance
CPT basic interpretation plots
Friction Ratio HAND AUGER
Rf (%)
86420 10
Depth (ft)
46444240383634323028262422201816141210
86 Friction Ratio Pore pressure HAND AUGER
u (psi)
0 100 200
Depth (ft)
46444240383634323028262422201816141210
86 Pore pressure
Insitu
SBT Plot HAND AUGER
Ic(SBT)
1 2 3 4
Depth (ft)
46444240383634323028262422201816141210
86 SBT Plot Soil Behaviour Type

HAND AUGER
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
46444240383634323028262422201816141210
86420
Soil Behaviour Type
Sand & silty sandSand & silty sandSilty sand & sandy siltClay & silty clayClaySilty sand & sandy siltSand & silty sandSand & silty sandClay & silty claySand & silty sandSilty sand & sandy siltSand & silty sandSand & silty sandSand & silty sandSand & silty sandSand & silty sandSand & silty sandSand & silty sandSilty sand & sandy siltSilty sand & sandy siltSilty sand & sandy siltSilty sand & sandy siltSilty sand & sandy siltSilty sand & sandy siltClay & silty claySilty sand & sandy siltVery dense/stif f soilSand & silty sand CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:00 AM 30Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4213.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

13.00 ft12.60Based on SBTNoN/A
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:

N/A
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-9 Cone resistance
qt (tsf)
0 100 200 300 400
Depth (ft)
46444240383634323028262422201816141210
86 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
46444240383634323028262422201816141210
86 SBTn Plot FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
46444240383634323028262422201816141210
86420
FS Plot
During earthq.

Vertical settlements

HAND AUGER
Settlement (in)
0 1 2 3
Depth (ft)
46444240383634323028262422201816141210
86420
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
Volumentric strain (%)
6543210
Depth (ft)
46444240383634323028262422201816141210
86420
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:00 AM 31Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain This software is licensed to: Leighton Group, Inc CPT name: CPT-9 Cone resistance
qt (tsf)
0 200 400
Depth (ft)
46444240383634323028262422201816141210
86 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
46444240383634323028262422201816141210
86 SBTn Plot Corrected norm. cone resista
Qtn,cs
0 10050 150 200
Depth (ft)
46444240383634323028262422201816141210
86 Corrected norm. cone resista FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
46444240383634323028262422201816141210
86420
FS Plot
During earthq.

Cyclic shear strain
Gamma max (%)
0 2010 30 40 50 60
Depth (ft)
46444240383634323028262422201816141210
86420
Cyclic shear strain Lateral displacements

HAND AUGER
Displacement (in)
0 5 10
Depth (ft)
46444240383634323028262422201816141210
86420
Lateral displacements
Estimation of post-earthquake lateral Displacements
Geometric parameters: Level ground (or gently sloping) with free face (L: 600.00 ft - H: 14.00 ft) CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:00 AM 32 Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq qt: Total cone resistance (cone resistance qc corrected for pore water effects) Ic: Soil Behaviour Type Index
Qtn,cs: Equivalent clean sand normalized CPT total cone resistance F.S.: Factor of safetyγmax: Maximum cyclic shear strain LDI: Lateral displacement index
Abbreviations Surface condition

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-10

13.00 ft

13.00 ft
1 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

No
N/A
N/A
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
4321
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
SBTn Plot CRR plot

HAND AUGER

CRR & CSR
0 0.2 0.4 0.6
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio HAND AUGER
Rf (%)
86420 10
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:00 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 33 This software is licensed to: Leighton Group, Inc CPT name: CPT-10 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Cone resistance
CPT basic interpretation plots
Friction Ratio HAND AUGER
Rf (%)
86420 10
Depth (ft)
37363534333231302928272625242322212019181716151413121110 98765
Friction Ratio Pore pressure HAND AUGER
u (psi)
0 5 10
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Pore pressure
Insitu
SBT Plot HAND AUGER
Ic(SBT)
1 2 3 4
Depth (ft)
37363534333231302928272625242322212019181716151413121110 98765
SBT Plot Soil Behaviour Type

HAND AUGER
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Soil Behaviour Type
Sand & silty sandSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSand & silty sandSilty sand & sandy siltSand & silty sandSand & silty sandSilty sand & sandy siltSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSandSand & silty sand CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:00 AM 34Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4213.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

13.00 ft12.60Based on SBTNoN/A
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:

N/A
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-10 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
37363534333231302928272625242322212019181716151413121110 98765
SBTn Plot FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
FS Plot
During earthq.

Vertical settlements

HAND AUGER
Settlement (in)
43210
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
Volumentric strain (%)
6543210
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:00 AM 35Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain This software is licensed to: Leighton Group, Inc CPT name: CPT-10 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
37363534333231302928272625242322212019181716151413121110 98765
SBTn Plot Corrected norm. cone resista
Qtn,cs
0 10050 150 200
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Corrected norm. cone resista FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
FS Plot
During earthq.

Cyclic shear strain
Gamma max (%)
0 2010 30 40 50 60
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Cyclic shear strain Lateral displacements

HAND AUGER
Displacement (in)
0 10 20
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Lateral displacements
Estimation of post-earthquake lateral Displacements
Geometric parameters: Level ground (or gently sloping) with free face (L: 380.00 ft - H: 14.00 ft) CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:00 AM 36 Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq qt: Total cone resistance (cone resistance qc corrected for pore water effects) Ic: Soil Behaviour Type Index
Qtn,cs: Equivalent clean sand normalized CPT total cone resistance F.S.: Factor of safetyγmax: Maximum cyclic shear strain LDI: Lateral displacement index
Abbreviations Surface condition

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-11

13.00 ft

13.00 ft
1 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

No
N/A
N/A
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
0 500
Depth (ft)
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
4321
36 35
34 33
32 31
30 29
28 27
26 25
24 23
22 21
20 19
18 17
16 15
14 13
12 11
10 9
8 7
6 5
SBTn Plot CRR plot

HAND AUGER

CRR & CSR
0 0.2 0.4 0.6
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio HAND AUGER
Rf (%)
86420 10
36 35
34 33
32 31
30 29
28 27
26 25
24 23
22 21
20 19
18 17
16 15
14 13
12 11
10 9
8 7
6 5
Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
4 2
0 FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:01 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 37 This software is licensed to: Leighton Group, Inc CPT name: CPT-11 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
363534333231302928272625242322212019181716151413121110
98765
Cone resistance
CPT basic interpretation plots
Friction Ratio HAND AUGER
Rf (%)
86420 10
Depth (ft)
363534333231302928272625242322212019181716151413121110
98765
Friction Ratio Pore pressure HAND AUGER
u (psi)
0 5 10
Depth (ft)
363534333231302928272625242322212019181716151413121110
98765
Pore pressure
Insitu
SBT Plot HAND AUGER
Ic(SBT)
1 2 3 4
Depth (ft)
363534333231302928272625242322212019181716151413121110
98765
SBT Plot Soil Behaviour Type

HAND AUGER
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
363534333231302928272625242322212019181716151413121110
9876543210
Soil Behaviour Type
Silty sand & sandy siltSand & silty sandSilty sand & sandy siltSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSilty sand & sandy siltSand & silty sandSand & silty sandSilty sand & sandy siltClay & silty clayClay & silty clayClay & silty claySand & silty sandSilty sand & sandy siltSand & silty sandSand & silty sandSand & silty sandSand & silty sandSandSand & silty sandSand & silty sandSand CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:01 AM 38Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4213.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

13.00 ft12.60Based on SBTNoN/A
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:

N/A
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-11 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
363534333231302928272625242322212019181716151413121110
98765
Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
363534333231302928272625242322212019181716151413121110
98765
SBTn Plot FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
363534333231302928272625242322212019181716151413121110
9876543210
FS Plot
During earthq.

Vertical settlements

HAND AUGER
Settlement (in)
0 1 2 3
Depth (ft)
363534333231302928272625242322212019181716151413121110
9876543210
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
Volumentric strain (%)
6543210
Depth (ft)
363534333231302928272625242322212019181716151413121110
9876543210
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:01 AM 39Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain This software is licensed to: Leighton Group, Inc CPT name: CPT-11 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
363534333231302928272625242322212019181716151413121110
98765
Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
363534333231302928272625242322212019181716151413121110
98765
SBTn Plot Corrected norm. cone resista
Qtn,cs
0 10050 150 200
Depth (ft)
363534333231302928272625242322212019181716151413121110
98765
Corrected norm. cone resista FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
363534333231302928272625242322212019181716151413121110
9876543210
FS Plot
During earthq.

Cyclic shear strain
Gamma max (%)
0 2010 30 40 50 60
Depth (ft)
363534333231302928272625242322212019181716151413121110
9876543210
Cyclic shear strain Lateral displacements

HAND AUGER
Displacement (in)
0 5 10
Depth (ft)
363534333231302928272625242322212019181716151413121110
9876543210
Lateral displacements
Estimation of post-earthquake lateral Displacements
Geometric parameters: Level ground (or gently sloping) with free face (L: 480.00 ft - H: 14.00 ft) CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:01 AM 40 Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq qt: Total cone resistance (cone resistance qc corrected for pore water effects) Ic: Soil Behaviour Type Index
Qtn,cs: Equivalent clean sand normalized CPT total cone resistance F.S.: Factor of safetyγmax: Maximum cyclic shear strain LDI: Lateral displacement index
Abbreviations Surface condition

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-12

13.00 ft

13.00 ft
1 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

No
N/A
N/A
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
0 500
Depth (ft)
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
4321
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
SBTn Plot CRR plot

HAND AUGER

CRR & CSR
0 0.2 0.4 0.6
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio HAND AUGER
Rf (%)
86420 10
36 34
32 30
28 26
24 22
20 18
16 14
12 10
8 6
Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:02 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 41 This software is licensed to: Leighton Group, Inc CPT name: CPT-12 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Cone resistance
CPT basic interpretation plots
Friction Ratio HAND AUGER
Rf (%)
86420 10
Depth (ft)
37363534333231302928272625242322212019181716151413121110 98765
Friction Ratio Pore pressure HAND AUGER
u (psi)
0 5 10
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Pore pressure
Insitu
SBT Plot HAND AUGER
Ic(SBT)
1 2 3 4
Depth (ft)
37363534333231302928272625242322212019181716151413121110 98765
SBT Plot Soil Behaviour Type

HAND AUGER
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Soil Behaviour Type
Silty sand & sandy siltSand & silty sandSand & silty sandSand & silty sandSand & silty sandSilty sand & sandy siltSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltClay & silty claySand & silty sandSand & silty sandSand & silty sand CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:02 AM 42Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4213.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

13.00 ft12.60Based on SBTNoN/A
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:

N/A
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-12 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
37363534333231302928272625242322212019181716151413121110 98765
SBTn Plot FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
FS Plot
During earthq.

Vertical settlements

HAND AUGER
Settlement (in)
543210
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
Volumentric strain (%)
6543210
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:02 AM 43Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain This software is licensed to: Leighton Group, Inc CPT name: CPT-12 Cone resistance
qt (tsf)
0 200 400 600
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
37363534333231302928272625242322212019181716151413121110 98765
SBTn Plot Corrected norm. cone resista
Qtn,cs
0 10050 150 200
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 98765
Corrected norm. cone resista FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
FS Plot
During earthq.

Cyclic shear strain
Gamma max (%)
0 2010 30 40 50 60
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Cyclic shear strain Lateral displacements

HAND AUGER
Displacement (in)
0 10 20 30
Depth (ft)
3837363534333231302928272625242322212019181716151413121110 9876543210
Lateral displacements
Estimation of post-earthquake lateral Displacements
Geometric parameters: Level ground (or gently sloping) with free face (L: 320.00 ft - H: 14.00 ft) CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:02 AM 44 Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq qt: Total cone resistance (cone resistance qc corrected for pore water effects) Ic: Soil Behaviour Type Index
Qtn,cs: Equivalent clean sand normalized CPT total cone resistance F.S.: Factor of safetyγmax: Maximum cyclic shear strain LDI: Lateral displacement index
Abbreviations Surface condition

LI Q UEFACTION ANALYSIS REPORT
Input parameters and analysis data
Analysis method:

Fines correction method:

Points to test:

Earthquake magnitude Mw:

Peak ground acceleration:

NCEER (1998)
NCEER (1998)
Based on Ic value

6.41 0.42
G.W.T. (in-situ):

G.W.T. (earthq.):

Average results interval:

Ic cut-off value:

Unit weight calculation:

Project title : City Ventures Santee 3 Location : Santee, California Leighton
San Diego, CA
CPT file : CPT-13

13.00 ft

13.00 ft
1 2.60
Based on SBT
Use fill:

Fill height:

Fill weight:

Trans. detect. applied:

Kσ applied:

No
N/A
N/A
Yes
Yes
Clay like behavior
applied:

Limit depth applied:

Limit depth:

MSF method:

Sands only
No
N/A
Method based
Cone resistance
qt (tsf)
0 200 400
Depth (ft)
50 48
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
4321
50 48
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 SBTn Plot CRR plot

HAND AUGER

CRR & CSR
0 0.2 0.4 0.6
50 48
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
CRR plot
During earthq.

Qtn,cs
0 10080604020 120 140 160 180 200
Cyclic Stress Ratio* (CSR*)

0.8 0.7

0.6 0.5

0.4 0.3

0.2 0.1
0 Liquefaction
No Liquefaction
Normalized friction ratio (%)

0.1 1 10
Normalized CPT penetration resistance
1 10
100
1,000
Friction Ratio HAND AUGER
Rf (%)
86420 10
50 48
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 Friction Ratio
Mw=71/2, sigma'=1 atm base curve Summary of liquefaction potential FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
50 48
46 44
42 40
38 36
34 32
30 28
26 24
22 20
18 16
14 12
10 8
6 4
2 0
FS Plot
During earthq.

Zone A1: Cyclic liquefaction likely depending on size and duration of cyclic loading Zone A2: Cyclic liquefaction and strength loss likely depending on loading and ground geometry
Zone B: Liquefaction and post-earthquake strength loss unlikely, check cyclic softening Zone C: Cyclic liquefaction and strength loss possible depending on soil plasticity, brittleness/sensitivity, strain to peak undrained strength and ground geometry CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:03 AM Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq 45 This software is licensed to: Leighton Group, Inc CPT name: CPT-13 Cone resistance
qt (tsf)
0 200 400
Depth (ft)
504846444240383634323028262422201816141210
86 Cone resistance
CPT basic interpretation plots
Friction Ratio HAND AUGER
Rf (%)
86420 10
Depth (ft)
504846444240383634323028262422201816141210
86 Friction Ratio Pore pressure HAND AUGER
u (psi)
0 20 40 60
Depth (ft)
504846444240383634323028262422201816141210
86 Pore pressure
Insitu
SBT Plot HAND AUGER
Ic(SBT)
1 2 3 4
Depth (ft)
504846444240383634323028262422201816141210
86 SBT Plot Soil Behaviour Type

HAND AUGER
SBT (Robertson et al. 1986)
9876543210 181716151413121110
Depth (ft)
504846444240383634323028262422201816141210
86420
Soil Behaviour Type
Silty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSilty sand & sandy siltSand & silty sandSilty sand & sandy siltSand & silty sandSand & silty sandSilty sand & sandy siltClay & silty clayClay & silty clayClay & silty clayClaySandSand & silty sandSilty sand & sandy siltVery dense/stif f soilVery dense/stif f soilVery dense/stif f soilVery dense/stif f soilVery dense/stif f soilSilty sand & sandy siltVery dense/stif f soilVery dense/stif f soil CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:03 AM 46Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Input parameters and analysis dataAnalysis method:

Fines correction method:Points to test:Earthquake magnitude Mw:

Peak ground acceleration:Depth to water table (insitu):

NCEER (1998)NCEER (1998)Based on Ic value6.410.4213.00 ft Depth to water table (erthq.):

Average results interval:

Ic cut-off value:Unit weight calculation:Use fill:Fill height:

13.00 ft12.60Based on SBTNoN/A
Fill weight:

Transition detect. applied:

Kσ applied:

Clay like behavior applied:Limit depth applied:Limit depth:

N/A
YesYes
Sands onlyNoN/A
SBT legend

1. Sensitive fine grained

2. Organic material3. Clay to silty clay

4. Clayey silt to silty5. Silty sand to sandy silt6. Clean sand to silty sand

7. Gravely sand to sand8. Very stiff sand to9. Very stiff fine grained This software is licensed to: Leighton Group, Inc CPT name: CPT-13 Cone resistance
qt (tsf)
0 200 400
Depth (ft)
504846444240383634323028262422201816141210
86 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
504846444240383634323028262422201816141210
86 SBTn Plot FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
504846444240383634323028262422201816141210
86420
FS Plot
During earthq.

Vertical settlements

HAND AUGER
Settlement (in)
43210
Depth (ft)
504846444240383634323028262422201816141210
86420
Vertical settlements
Estimation of post-earthquake settlements
Strain plot
Volumentric strain (%)
6543210
Depth (ft)
504846444240383634323028262422201816141210
86420
Strain plot
CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:03 AM 47Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq Abbreviationsqt:

Ic:

FS:

Volumentric strain:

Total cone resistance (cone resistance qc corrected for pore water effects) Soil Behaviour Type IndexCalculated Factor of Safety against liquefactionPost-liquefaction volumentric strain This software is licensed to: Leighton Group, Inc CPT name: CPT-13 Cone resistance
qt (tsf)
0 200 400
Depth (ft)
504846444240383634323028262422201816141210
86 Cone resistance SBTn Plot HAND AUGER
Ic (Robertson 1990)
1 2 3 4
Depth (ft)
504846444240383634323028262422201816141210
86 SBTn Plot Corrected norm. cone resista
Qtn,cs
0 10050 150 200
Depth (ft)
504846444240383634323028262422201816141210
86 Corrected norm. cone resista FS Plot

HAND AUGER
Factor of safety
0 0.5 1 1.5 2
Depth (ft)
504846444240383634323028262422201816141210
86420
FS Plot
During earthq.

Cyclic shear strain
Gamma max (%)
0 2010 30 40 50 60
Depth (ft)
504846444240383634323028262422201816141210
86420
Cyclic shear strain Lateral displacements

HAND AUGER
Displacement (in)
0 10 20
Depth (ft)
504846444240383634323028262422201816141210
86420
Lateral displacements
Estimation of post-earthquake lateral Displacements
Geometric parameters: Level ground (or gently sloping) with free face (L: 180.00 ft - H: 12.00 ft) CLiq v.3.0.3.2 - CPT Liquefaction Assessment Software - Report created on: 1/31/2024, 11:35:03 AM 48 Project file: P:\INFOCUS PROJECTS\11501-12000\11832-City Ventures\002 Santee 3 Geotechnical\Analyses\Lat Spread\Santee 3.clq qt: Total cone resistance (cone resistance qc corrected for pore water effects) Ic: Soil Behaviour Type Index
Qtn,cs: Equivalent clean sand normalized CPT total cone resistance F.S.: Factor of safetyγmax: Maximum cyclic shear strain LDI: Lateral displacement index
Abbreviations Surface condition

APPENDIX E
General Earthwork and Grading Specifications for
Rough Grading
LEIGHTON AND ASSOCIATES, INC.

General Earthwork and Grading Specifications
-1-

1.0 General

1.1 Intent
These General Earthwork and Grading Specifications are for the grading and earthwork shown on the approved grading plan(s) and/or indicated in the geotechnical report(s). These Specifications are a part of the recommendations contained in the geotechnical report(s). In case of conflict, the specific recommendations in the geotechnical report shall supersede these more general Specifications. Observations of the earthwork by the project Geotechnical Consultant during the course of grading may result in new or revised recommendations that could supersede these specifications or the recommendations in the geotechnical report(s).

1.2 The Geotechnical Consultant of Record
Prior to commencement of work, the owner shall employ the Geotechnical Consultant of Record (Geotechnical Consultant). The Geotechnical Consultants shall be responsible for reviewing the approved geotechnical report(s) and accepting the adequacy of the preliminary geotechnical findings, conclusions, and recommendations prior to the commencement of the grading.

Prior to commencement of grading, the Geotechnical Consultant shall review the "work plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient personnel to perform the appropriate level of observation, mapping, and compaction testing.

During the grading and earthwork operations, the Geotechnical Consultant shall observe, map, and document the subsurface exposures to verify the geotechnical design assumptions. If the observed conditions are found to be significantly different than the interpreted assumptions during the design phase, the Geotechnical Consultant shall inform the owner, recommend appropriate changes in design to accommodate the observed conditions, and notify the review agency where required. Subsurface areas to be geotechnically observed, mapped, elevations recorded, and/or tested include natural ground after it has been cleared for receiving fill but before fill is placed, bottoms of all "remedial removal" areas, all key bottoms, and benches made on sloping ground to receive fill.

The Geotechnical Consultant shall observe the moisture-conditioning and processing of the subgrade and fill materials and perform relative compaction testing of fill to determine the attained level of compaction. The Geotechnical Consultant shall provide the test results to the owner and the Contractor on a routine and frequent basis.

LEIGHTON AND ASSOCIATES, INC.

General Earthwork and Grading Specifications
-2-

1.3 The Earthwork Contractor
The Earthwork Contractor (Contractor) shall be qualified, experienced, and knowledgeable in earthwork logistics, preparation and processing of ground to receive fill, moisture-conditioning and processing of fill, and compacting fill.

The Contractor shall review and accept the plans, geotechnical report(s), and these Specifications prior to commencement of grading. The Contractor shall be solely responsible for performing the grading in accordance with the plans and specifications.

The Contractor shall prepare and submit to the owner and the Geotechnical Consultant a work plan that indicates the sequence of earthwork grading, the number of "spreads" of work and the estimated quantities of daily earthwork contemplated for the site prior to commencement of grading. The Contractor shall inform the owner and the Geotechnical Consultant of changes in work schedules and updates to the work plan at least 24 hours in advance of such changes so that appropriate observations and tests can be planned and accomplished. The Contractor shall not assume that the Geotechnical Consultant is aware of all grading operations.

The Contractor shall have the sole responsibility to provide adequate equipment and methods to accomplish the earthwork in accordance with the applicable grading codes and agency ordinances, these Specifications, and the recommendations in the approved geotechnical report(s) and grading plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soil, improper moisture condition, inadequate compaction, insufficient buttress key size, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the Geotechnical Consultant shall reject the work and may recommend to the owner that construction be stopped until the conditions are rectified.

2.0 Preparation of Areas to be Filled

2.1 Clearing and Grubbing
Vegetation, such as brush, grass, roots, and other deleterious material shall be sufficiently removed and properly disposed of in a method acceptable to the owner, governing agencies, and the Geotechnical Consultant.

The Geotechnical Consultant shall evaluate the extent of these removals depending on specific site conditions. Earth fill material shall not contain more than 1 percent of organic materials (by volume). No fill lift shall contain more than 5 percent of organic matter. Nesting of the organic materials shall not be allowed.

LEIGHTON AND ASSOCIATES, INC.

General Earthwork and Grading Specifications
-3-
If potentially hazardous materials are encountered, the Contractor shall stop work in the affected area, and a hazardous material specialist shall be informed immediately for proper evaluation and handling of these materials prior to continuing to work in that area.

As presently defined by the State of California, most refined petroleum products (gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the ground may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not be allowed.

2.2 Processing
Existing ground that has been declared satisfactory for support of fill by the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches.

Existing ground that is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until soils are broken down and free of large clay lumps or clods and the working surface is reasonably uniform, flat, and free of uneven features that would inhibit uniform compaction.

2.3 Overexcavation
In addition to removals and overexcavations recommended in the approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic-rich, highly fractured or otherwise unsuitable ground shall be overexcavated to competent ground as evaluated by the Geotechnical Consultant during grading.

2.4 Benching
Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical units), the ground shall be stepped or benched. Please see the Standard Details for a graphic illustration. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet deep, into competent material as evaluated by the Geotechnical Consultant. Other benches shall be excavated a minimum height of 4 feet into competent material or as otherwise recommended by the Geotechnical Consultant. Fill placed on ground sloping flatter than 5:1 shall also be benched or otherwise overexcavated to provide a flat subgrade for the fill.

2.5 Evaluation/Acceptance of Fill Areas
All areas to receive fill, including removal and processed areas, key bottoms, and benches, shall be observed, mapped, elevations recorded, and/or tested prior to being accepted by the Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain a written acceptance from the Geotechnical Consultant LEIGHTON AND ASSOCIATES, INC.

General Earthwork and Grading Specifications
-4-
prior to fill placement. A licensed surveyor shall provide the survey control for determining elevations of processed areas, keys, and benches.

3.0 Fill Material

3.1 General
Material to be used as fill shall be essentially free of organic matter and other deleterious substances evaluated and accepted by the Geotechnical Consultant prior to placement. Soils of poor quality, such as those with unacceptable gradation, high expansion potential, or low strength shall be placed in areas acceptable to the Geotechnical Consultant or mixed with other soils to achieve satisfactory fill material.

3.2 Oversize
Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 8 inches, shall not be buried or placed in fill unless location, materials, and placement methods are specifically accepted by the Geotechnical Consultant. Placement operations shall be such that nesting of oversized material does not occur and such that oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 vertical feet of finish grade or within 2 feet of future utilities or underground construction.

3.3 Import
If importing of fill material is required for grading, proposed import material shall meet the requirements of Section 3.1. The potential import source shall be given to the Geotechnical Consultant at least 48 hours (2 working days) before importing begins so that its suitability can be determined and appropriate tests performed.

4.0 Fill Placement and Compaction

4.1 Fill Layers
Approved fill material shall be placed in areas prepared to receive fill (per Section 3.0) in near-horizontal layers not exceeding 8 inches in loose thickness.

The Geotechnical Consultant may accept thicker layers if testing indicates the grading procedures can adequately compact the thicker layers. Each layer shall be spread evenly and mixed thoroughly to attain relative uniformity of material and moisture throughout.

LEIGHTON AND ASSOCIATES, INC.

General Earthwork and Grading Specifications
-5-

4.2 Fill Moisture Conditioning
Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly over optimum.

Maximum density and optimum soil moisture content tests shall be performed in accordance with the American Society of Testing and Materials (ASTM Test Method D1557).

4.3 Compaction of Fill
After each layer has been moisture-conditioned, mixed, and evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test Method D1557). Compaction equipment shall be adequately sized and be either specifically designed for soil compaction or of proven reliability to efficiently achieve the specified level of compaction with uniformity.

4.4 Compaction of Fill Slopes
In addition to normal compaction procedures specified above, compaction of slopes shall be accomplished by backrolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods producing satisfactory results acceptable to the Geotechnical Consultant. Upon completion of grading, relative compaction of the fill, out to the slope face, shall be at least 90 percent of maximum density per ASTM Test Method D1557.

4.5 Compaction Testing
Field-tests for moisture content and relative compaction of the fill soils shall be performed by the Geotechnical Consultant. Location and frequency of tests shall be at the Consultant's discretion based on field conditions encountered.

Compaction test locations will not necessarily be selected on a random basis.

Test locations shall be selected to verify adequacy of compaction levels in areas that are judged to be prone to inadequate compaction (such as close to slope faces and at the fill/bedrock benches).

4.6 Frequency of Compaction Testing
Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment. In addition, as a guideline, at least one test shall be taken on slope faces for each 5,000 square feet of slope face and/or each 10 feet of vertical height of slope. The Contractor shall assure that fill construction is such that the testing schedule can be accomplished by the Geotechnical Consultant. The Contractor shall stop or slow down the earthwork construction if these minimum standards are not met.

LEIGHTON AND ASSOCIATES, INC.

General Earthwork and Grading Specifications
-6-

4.7 Compaction Test Locations
The Geotechnical Consultant shall document the approximate elevation and horizontal coordinates of each test location. The Contractor shall coordinate with the project surveyor to assure that sufficient grade stakes are established so that the Geotechnical Consultant can determine the test locations with sufficient accuracy. At a minimum, two grade stakes within a horizontal distance of 100 feet and vertically less than 5 feet apart from potential test locations shall be provided.

5.0 Subdrain Installation
Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the grading plan, and the Standard Details. The Geotechnical Consultant may recommend additional subdrains and/or changes in subdrain extent, location, grade, or material depending on conditions encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line and grade after installation and prior to burial. Sufficient time should be allowed by the Contractor for these surveys.

6.0 Excavation
Excavations, as well as over-excavation for remedial purposes, shall be evaluated by the Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical plans are estimates only. The actual extent of removal shall be determined by the Geotechnical Consultant based on the field evaluation of exposed conditions during grading. Where fill-over-cut slopes are to be graded, the cut portion of the slope shall be made, evaluated, and accepted by the Geotechnical Consultant prior to placement of materials for construction of the fill portion of the slope, unless otherwise recommended by the Geotechnical Consultant.

7.0 Trench Backfills

7.1 Safety
The Contractor shall follow all OSHA and Cal/OSHA requirements for safety of trench excavations.

LEIGHTON AND ASSOCIATES, INC.

General Earthwork and Grading Specifications
-7-

7.2 Bedding and Backfill
All bedding and backfill of utility trenches shall be performed in accordance with the applicable provisions of Standard Specifications of Public Works Construction. Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The bedding shall be placed to 1 foot over the top of the conduit and densified. Backfill shall be placed and densified to a minimum of 90 percent of relative compaction from 1 foot above the top of the conduit to the surface.

The Geotechnical Consultant shall test the trench backfill for relative compaction.

At least one test should be made for every 300 feet of trench and 2 feet of fill.

7.3 Lift Thickness
Lift thickness of trench backfill shall not exceed those allowed in the Standard Specifications of Public Works Construction unless the Contractor can demonstrate to the Geotechnical Consultant that the fill lift can be compacted to the minimum relative compaction by his alternative equipment and method.

7.4 Observation and Testing
The densification of the bedding around the conduits shall be observed by the Geotechnical Consultant.
 




  
 





 


 
 



 



 






 
 


 

















 










 






 














 





 








 


 










 











































 

























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Appendix D-2
Geotechnical Investigation
Corona Office
Phone: 951.509.7090

CITY VENTURES January 29, 2025
3121 Michelson Drive, Suite 150 Project No. 1-0572
Irvine, California 92612
Attention: Mr. Michael You
Subject: GEOTECHNICAL INVESTIGATION
Southwest of Cottonwood Avenue and Park Center Drive,
City of Santee, San Diego County, California
References: See Appendix
Dear Mr. You:

Alta California Geotechnical, Inc. (Alta) is pleased to present this geotechnical investigation for the proposed development of the subject site located southwest of Cottonwood Avenue and Park Center Drive in the City of Santee, San Diego County, California. This report is based upon a recent subsurface investigation conducted by Alta and others, laboratory testing, a review of published geologic maps, and Alta’s staff’s experience with similar projects in this vicinity.

Alta’s review of the data indicates that the proposed development is feasible, from a geotechnical perspective, provided that the recommendations presented in this report are incorporated into the grading and improvement plans and implemented during site development.

Included in this report are:
 Discussion of the site geotechnical conditions.
 Recommendations for remedial and site grading, including unsuitable soil removals and rock disposal.
 Geotechnical site construction recommendations.
 Preliminary foundation design parameters.

Project Number 1-0572 Page ii
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

If you have any questions or should you require any additional information, please contact the undersigned at (951) 509-7090. Alta appreciates the opportunity to provide geotechnical consulting services for your project.

Sincerely,
Alta California Geotechnical, Inc. Reviewed By:
________________________________
LOGAN A. MARQUETTE
Civil Engineering Associate
________________________________
YOUSSEF F. HIJAZI
Engineering Geology Associate
___________________________________
SCOTT A. GRAY/RGE 2857
Reg. Exp.: 12-31-26
Registered Geotechnical Engineer
President
_________________________________
FRANK J. ECHENIQUE/CEG 2134
Reg. Exp.: 9-30-26
Certified Engineering Geologist
Manager of Geologic Services
Distribution: (1) Addressee
LAM:YFH: SAG: FJE: eg-1-0572, January 29, 2025 (Geotechnical Investigation, Cottonwood & Park Center, Santee) Project Number 1-0572 Page iii
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

1.0 INTRODUCTION ................................................................................................................... 1

1.1 Purpose ......................................................................................................................... 1

1.2 Scope of Work ............................................................................................................... 1

1.3 Report Limitations ......................................................................................................... 2

2.0 PROJECT DESCRIPTION ........................................................................................................ 2

2.1 Site Location and Existing Conditions ............................................................................ 2

2.2 Proposed Development ................................................................................................. 2

3.0 SITE INVESTIGATION ............................................................................................................ 3

3.1 Current Subsurface Investigation .................................................................................. 3

3.2 Infiltration Testing ......................................................................................................... 3

3.3 Previous Subsurface Investigation ................................................................................. 4

3.4 Previous Infiltration Testing .......................................................................................... 4

4.0 GEOLOGIC CONDITIONS ...................................................................................................... 5

4.1 Geologic and Geomorphic Setting ................................................................................. 5

4.2 Stratigraphy ................................................................................................................... 5

4.2.1 Young Alluvial Deposits (Map symbol Qya) ........................................................... 5

4.3 Geologic Structure ......................................................................................................... 6

4.3.1 Tectonic Framework .............................................................................................. 6

4.3.2 Regionally Mapped Active Faults ........................................................................... 7

4.3.3 Geologic Structure ................................................................................................. 7

4.4 Groundwater ................................................................................................................. 7

4.5 Earthquake Hazards ...................................................................................................... 7

4.5.1 Local and Regional Faulting ................................................................................... 7

4.5.2 Seismicity ............................................................................................................... 8

4.5.3 Surface Rupture ..................................................................................................... 8

4.5.4 Liquefaction ........................................................................................................... 8

4.5.5 Dry Sand Settlement ............................................................................................ 10

5.0 ENGINEERING PROPERTIES AND ANALYSIS ....................................................................... 11

5.1 Materials Properties .................................................................................................... 11

5.1.1 Excavation Characteristics ................................................................................... 11

5.1.2 Compressibility .................................................................................................... 11

5.1.3 Hydro-Consolidation ............................................................................................ 11

5.1.4 Expansion Potential ............................................................................................. 12

5.1.5 Earthwork Adjustments ....................................................................................... 12

5.1.6 Chemical Analyses ............................................................................................... 12

5.2 Engineering Analysis .................................................................................................... 13

5.2.1 Bearing Capacity and Lateral Earth Pressures ...................................................... 13 Project Number 1-0572 Page iv
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

6.0 CONCLUSIONS AND RECOMMENDATIONS ........................................................................ 13

6.1 Remedial Grading Recommendations ......................................................................... 13

6.1.1 Site Preparation ................................................................................................... 13

6.1.2 Unsuitable Soil Removals .................................................................................... 14

6.2 General Earthwork Recommendations........................................................................ 15

6.2.1 Compaction Standards ........................................................................................ 15

6.2.2 Groundwater/Seepage ........................................................................................ 15

6.2.3 Documentation of Removals ............................................................................... 15

6.2.4 Treatment of Removal Bottoms .......................................................................... 16

6.2.5 Fill Placement ...................................................................................................... 16

6.2.6 Moisture Content ................................................................................................ 16

6.2.7 Mixing .................................................................................................................. 16

6.2.8 Import Soils ......................................................................................................... 16

6.2.9 Utility Trenches ................................................................................................... 17

6.2.9.1 Excavation ........................................................................................................... 17

6.2.9.2 Backfill ................................................................................................................. 17

6.2.10 Backcut Stability .................................................................................................. 18

6.3 Liquefaction ................................................................................................................. 19

6.4 Storm Water Infiltration Systems ................................................................................ 20

6.5 Boundary Conditions ................................................................................................... 20

7.0 DESIGN CONSIDERATIONS ................................................................................................. 20

7.1 Structural Design ......................................................................................................... 20

7.1.1 Foundation Design ............................................................................................... 21

7.1.2 Post-Tensioned Slabs/Foundation Design Recommendations ............................. 21

7.2 Moisture Barrier .......................................................................................................... 22

7.3 Seismic Design ............................................................................................................. 22

7.4 Block Walls .................................................................................................................. 23

7.5 Footing Excavations ..................................................................................................... 24

7.6 Retaining Wall Design .................................................................................................. 24

7.7 Exterior Slabs and Walkways ....................................................................................... 25

7.7.1 Subgrade Compaction ......................................................................................... 25

7.7.2 Subgrade Moisture .............................................................................................. 26

7.7.3 Concrete Slab Thickness ...................................................................................... 26

7.7.4 Concrete Slab Reinforcement .............................................................................. 26

7.7.5 Control Joints ....................................................................................................... 26

7.8 Concrete Design .......................................................................................................... 26

7.9 Corrosion ..................................................................................................................... 27

7.10 Pavement Design ......................................................................................................... 27 Project Number 1-0572 Page v
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

7.11 Site Drainage ............................................................................................................... 28

7.12 Utility Design ............................................................................................................... 28

8.0 LOT MAINTENANCE ........................................................................................................... 29

8.1 Lot Drainage ................................................................................................................ 29

8.2 Burrowing Animals ...................................................................................................... 29

9.0 FUTURE PLAN REVIEWS ..................................................................................................... 29

10.0 CLOSURE ...................................................................................................................... 30

10.1 Geotechnical Review ................................................................................................... 30

10.2 Limitations ................................................................................................................... 30 APPENDIX A – References
APPENDIX B – Subsurface Investigation
APPENDIX B-1 – Previous Subsurface Investigation (Leighton, 2024) APPENDIX B-2 – Previous Subsurface Investigation (Leighton, 2017) APPENDIX B-3 – Previous Subsurface Investigation (Law Crandall, 1999) APPENDIX C – Laboratory Testing
APPENDIX D – Liquefaction Analysis
APPENDIX E – Maintenance and Improvement Considerations APPENDIX F – Earthwork Specifications
APPENDIX G – Grading Details
Project Number 1-0572 Page 1
January 29, 2025
Corona Office
Phone: 951.509.7090

1.0 INTRODUCTION
The following report presents Alta’s findings, conclusions, and geotechnical recommendations for the proposed development located southwest of Cottonwood Avenue and Park Center Drive in the City of Santee, San Diego County, California.

1.1 Purpose
The purpose of this report is to examine the existing geotechnical conditions and evaluate their impacts on the proposed development depicted on the accompanying conceptual site plan. This report is suitable for submittal to governing agencies and for use as a bid document.

1.2 Scope of Work
Alta’s Scope of Work for this geotechnical investigation included the following:
 Review of the referenced literature, maps, and aerial photos (Appendix A).
 Site geologic mapping.
 Excavating, logging, and sampling of four (4) hollow stem auger borings to a maximum depth of approximately 47.0 feet below existing grade (Appendix B).
 Conducting laboratory testing on samples obtained during our investigation (Appendix C).
 Performing an infiltration study with two (2) additional borings to depths of 10.0- and 5.0-ft bgs to provide an assessment of the infiltration characteristics of the onsite soils and their impact on storm water disposal.
 Review of the Preliminary Geotechnical Investigation, prepared by Leighton and Associates, Inc. (Leighton, 2024). Subsurface data prepared by Leighton is presented in Appendix B-1 and B-2; subsurface data referenced by Leighton is presented in Appendix B-3.
 Evaluating engineering geologic and geotechnical engineering data, including laboratory data, to develop recommendations for site remedial grading, import soil, foundations and utilities.
 Preparing this report and accompanying exhibits.

Project Number 1-0572 Page 2
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

1.3 Report Limitations
The conclusions and recommendations presented in this report are based on the field and laboratory information generated during this investigation, and a review of the referenced reports. The materials adjacent to or beneath those observed may have different characteristics than those observed, and no representations are made as to the quality or extent of the materials not observed. The information contained in this report is intended to be used as a bid document and preliminary construction cost estimates.

2.0 PROJECT DESCRIPTION

2.1 Site Location and Existing Conditions
The irregular-shaped, approximately ±21.5-acre, site is relatively flat and sloping gently to the west. Six tall trees occupy the eastern portion of the site, and tall bushes occupy the majority of the northwestern edge. The site is bounded to the west by a park, to the north by a parking lot and vacant property, and to the south by a pond and the San Diego River. Historic aerial images are available as far back as 1953 and indicate the site was originally vacant. The site has remained unchanged since.

2.2 Proposed Development
Alta anticipates that the site will be developed into a single-family residential development consisting of 155 row homes and 136 townhomes. Alta anticipates that conventional cut-and-fill grading techniques will be used to develop the site for the support of wood-frame construction with shallow foundations and reinforced concrete slabs-on-grade, and associated improvements.

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3.0 SITE INVESTIGATION

3.1 Current Subsurface Investigation
Alta conducted a subsurface investigation on January 6th of 2025, consisting of the drilling, logging, and select sampling of four (4) hollow-stem auger borings to a maximum depth of 47.0 feet below the ground surface. The locations of the exploratory excavations are shown on Plate 1 and the logs are presented in Appendix B.

Laboratory testing was performed on ring and bulk samples obtained during the field investigation. A brief description of the laboratory test procedures and the test results are presented in Appendix C.

3.2 Infiltration Testing
It is Alta’s understanding that the project may utilize infiltration systems for storm water disposal. Details of the system are not known at this time.

Infiltration testing was undertaken using two (2) borings to depth of 10.0- and

5.0-ft bgs (P-1 and P-2). The testing was performed in general accordance with the County of San Diego Standards. The testing wells were presoaked at least 24 hours prior to testing. During testing, the water level readings were recorded every 30 to 10 minutes until the readings stabilized.

The data was then adjusted to provide an appropriate infiltration rate utilizing the Porchet Method. The resulting infiltration rates are presented in Table 3-1.

The results do not include a factor of safety. Recommendations for infiltration BMP design are presented in Section 6.3.

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Table 3-1
Summary of Infiltration Testing
(No Factor of Safety)
Test Designation P-1 P-2
Approximate Depth of Test 10.0 ft 5.0 ft
Final Time Interval 10 minutes 10 minutes
Radius of Test Hole 4 inches 4 inches
Tested Infiltration Rate 15.6 in/hr 12.3 in/hr

3.3 Previous Subsurface Investigation
Law Crandall conducted a field investigation on April 6th, 1999 that included a boring within the subject site. The boring log is presented in Appendix B.

Leighton and Associates, Inc., (Leighton) conducted a subsurface investigation on October 26, 2017 consisting of the excavation of seven (7) CPT soundings to a maximum depth of 51.5 feet below the ground surface. Leighton conducted an additional subsurface investigation on April 24, 2023 consisting of the excavation of six (6) CPT soundings to a maximum depth of 51.5 feet below the ground surface and the excavation of three (3) percolation tests borings to a max depth of 3.0 feet below the ground surface. The boring logs are presented in Appendix B, and the lab results are presented in Appendix C.

3.4 Previous Infiltration Testing
Infiltration testing was performed by Leighton utilizing percolation methods in accordance with County of San Diego Standards (Leighton, 2024). Measured percolation rates were converted to infiltration rates utilizing the Porchet method. The resulting field infiltration rates, with no factor of safety, are presented below in Table 3-2. Recommendations for infiltration BMP design are presented in Section 6.3.

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Table 3-2
Summary of Infiltration Testing
(With Factor of Safety)
Test Designation P-1 P-2 P-3
Approximate Depth of Test 3.0 ft 3.0 ft 3.0 ft
Measured Percolation Rate 1.1 min/in 0.95 min/in 1.0 min/in Calculated Infiltration Rate 2.35 in/hr 3.04 in/hr 2.86 in/hr

4.0 GEOLOGIC CONDITIONS

4.1 Geologic and Geomorphic Setting
Regionally, the subject site is located in the Peninsular Ranges geomorphic province, which characterizes the southwest portion of Southern California where major right-lateral strike slip active fault zones predominately trend northwest-southeast. The Peninsular Ranges province is composed of plutonic and metamorphic rock, lesser amounts of Tertiary volcanic and sedimentary rock, and Quaternary drainage in-fills and minor sedimentary veneers. The Peninsular Ranges are further divisible into northwest-trending sub-blocks that extend south into Baja California and terminate to the north against the Transverse Ranges province.

4.2 Stratigraphy
Based on Alta’s review of geologic literature and our subsurface investigation the site is underlain by young alluvial fan deposits. A description of the geologic units encountered are described below.

4.2.1 Young Alluvial Deposits (Map symbol Qya)
The young, Holocene age alluvial deposits observed onsite primarily consists of silty sand, sand, clayey sand, and a minor lense of clay. The very fine to coarse grained silty sand observed onsite ranges from brown, dark gray, and brownish dark gray in a dry to wet and loose to medium dense condition. The very fine to coarse grained sand observed onsite ranges from gray, brownish gray, and dark gray in a dry to slightly moist Project Number 1-0572 Page 6
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and medium dense to very dense condition. The fine grained clayey sand onsite was observed to be yellowish gray in a slightly moist to moist and hard condition. The minor silty clay lens observed onsite is brown in a wet and firm condition. This unit was logged to a depth of 47.0 feet below the ground surface.

4.3 Geologic Structure

4.3.1 Tectonic Framework
Jennings (1985) defined eight structural provinces within California that have been classified by predominant regional fault trends and similar fold structure. These provinces are in turn divided into blocks and sub-blocks that are defined by “major Quaternary faults”. These blocks and subblocks exhibit similar structural features. Within this framework, the subject site is located within Structural Province I, which is controlled by the dominant northwest trend of the San Andreas Fault and is divided into two blocks, the Coast Range Block and the Peninsular Range Block.

The Peninsular Ranges Block, on which this site is located, is characterized by parallel, northwest trending faults that exhibit right lateral strike-slip movement. These faults are terminated by the Transverse Ranges block to the north and extend southward to the Baja Peninsula. These northwest trending faults divide the Peninsular Range block into eight sub-blocks. The subject site is located on the Santa Ana sub-block, one of eight sub-blocks, which is bound on the east by the Whittier-Elsinore fault zone and on the west by Newport-Inglewood fault zone.

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4.3.2 Regionally Mapped Active Faults
Several large, active fault systems, including the NewportInglewood/Rose Canyon and Elsinore faults, occur in the region surrounding the subject site. These fault systems have been studied extensively and in a large part control the geologic structure of southern California.

4.3.3 Geologic Structure
Based upon our site investigation and literature review, the onsite alluvial deposits are of Quaternary-age and are not fractured, folded, or faulted.

4.4 Groundwater
Groundwater was encountered during Alta’s recent investigation at depths of

18.7, 14.7, 16.8, and 16.2 feet below the ground surface in borings B-1, B-2, B-3, and B-4, respectively. The most recent groundwater data obtained in 2024 from the nearest monitoring well, located approximately 1.1 miles southwest of the subject site, Site Code 328442N1169971W001, indicates the groundwater in the area was at 11.8 feet below the ground surface at that time (CDWR, 2024).

4.5 Earthquake Hazards
The subject site is located in southern California, which is a tectonically active region. The type and magnitude of seismic hazards affecting a site are dependent on the distance to the causative fault and the intensity and magnitude of the seismic event. The seismic hazard may be primary, such as surface rupture and/or ground shaking, or secondary, such as liquefaction and/or ground lurching.

4.5.1 Local and Regional Faulting
The site is located on the northwestern portion of the Santa Ana subblock. The closest known active faults and their distances to the site are presented in Table 4-1 below.

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TABLE 4-1
Local and Regional Faulting
Fault Zone Distance to Fault Zone
Newport-Inglewood 14.0 miles
Rose Canyon 14.0 miles
Palos Verdes 26.4 miles
Coronado Bank 26.4 miles
Elsinore 27.6 miles

4.5.2 Seismicity
Ground shaking hazards caused by earthquakes along other active regional faults exist. The 2022 California Building Code requires usemodified spectral accelerations and velocities for most structural designs.

Seismic design parameters using soil profile types identified in the 2022 California Building Code are presented in Section 7.3.

4.5.3 Surface Rupture
Active faults are not known to exist within the project and a review of Special Publication 42 indicates the site is not within a California State designated earthquake fault zone. Accordingly, the potential for fault surface rupture on the subject site is low.

4.5.4 Liquefaction
Seismic agitation of relatively loose saturated sands, silty sands, and some silts can result in a buildup of pore pressure. If the pore pressure exceeds the overburden stresses, a temporary quick condition known as liquefaction can occur. Liquefaction effects can manifest in several ways including: 1) loss of bearing; 2) lateral spread; 3) dynamic settlement; and 4) flow failure. Lateral spreading has typically been the most damaging mode of failure.

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In general, the more recent that a sediment has been deposited, the more likely it will be susceptible to liquefaction. Other factors that must be considered are groundwater, confining stresses, relative density, and the intensity and duration of seismically induced ground shaking.

Alta performed a liquefaction analysis utilizing CPT data obtained during the previous investigations to determine the liquefaction potential of the underlying soils. A description of Alta’s analysis and calculations are presented in Appendix D of this report. A groundwater level of 10 feet below the ground surface was assumed. The results of our findings are discussed below under the heading of the specific types of liquefaction which can be manifested during seismic shaking. Conclusions regarding liquefaction are presented in Section 6.3.
 Loss of Bearing:

Liquefaction can potentially cause bearing failure due to ground softening and near-failure in bearing. Further discussion of mitigation strategies to address the potential for loss of bearing is presented in Section 6.3. Based on the liquefaction remediation recommendations presented in this report, Alta anticipates that the potential for loss of bearing will be minimal upon completion of construction.
 Lateral Spreading:

The lateral displacement of surficial blocks of sediment can occur as a result of liquefaction in a subsurface layer. The most pervasive forms of lateral spreading typically involve sites located near a "free-face" (large slopes, channels, etc.), however, it has been noted that lateral spreading can occur on sites with gently sloping (1% or more) ground, such as the subject site.

Determination of the potential for lateral spread is based on the presence of continuous potentially liquefiable soil layers underneath the structures, the presence of lateral confinement, and various analyses such as empirical modeling. Bartlett, Hansen and Youd (2002) states that surface manifestation of lateral Project Number 1-0572 Page 10
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spread is typically limited to sites with liquefiable soils within 10 meters (32 feet) of grade, and that sites underlain by soils with (N1)60 values 15 and greater do not experience significant displacements from earthquakes with magnitudes less than 8.

Based on our liquefaction analysis, there is a high potential for lateral spreading to occur in the onsite soils. Mitigation strategies are discussed in Section 6.3 of this report.
 Settlement:

Settlement due to seismic shaking can occur as a result of both liquefaction of saturated sediments or rearrangement of dry sand particles. Based on our analysis, settlements on the order of 7.8 inches can occur during seismic shaking. A discussion of settlement analysis results as well as mitigation strategies are presented in Section 6.3. Dynamic settlement design
recommendations are presented in Section 7.1.
 Flow Failure:

Due to the relatively flat nature of the site, and the relatively horizontal deposition of the underlying deposits, the potential for flow failure onsite is considered minimal.

4.5.5 Dry Sand Settlement
Dry sand settlement is the process of non-uniform settlement of the ground surface during a seismic event. Based on our subsurface investigation, our removal/recompaction recommendations, and recommendations for ground improvement, the potential for dry sand settlement is anticipated to be minimal. Design dynamic settlement parameters are presented in Table 7-1.

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5.0 ENGINEERING PROPERTIES AND ANALYSIS

5.1 Materials Properties
Presented herein is a general discussion of the engineering properties of the onsite materials that will be encountered during construction of the proposed project. Descriptions of the soil (Unified Soil Classification System) are presented on the boring logs in Appendix B.

5.1.1 Excavation Characteristics
Based on the data provided from the subsurface investigations, it is our opinion that the onsite materials possess favorable excavation characteristics such that conventional earth moving equipment can be utilized.

5.1.2 Compressibility
The upper portions of the young alluvium are considered compressible and unsuitable to support the proposed improvements. Recommended removal depths are presented in Section 6.1.2.

5.1.3 Hydro-Consolidation
Hydro-consolidation is the effect of introducing water into soil that is prone to collapse. Upon loading and initial wetting, the soil structure and apparent strength are altered resulting in almost immediate settlement.

That settlement can have adverse impacts on engineered structures, particularly in areas where it is manifested differentially. Differential settlements are typically associated with differential wetting, irregularities in the subsurface soil conditions, or irregular loading patterns.

Based on laboratory testing results presented in Appendix C, there minimal potential for hydro-collapse to occur within the young alluvium onsite. Upon the completion of remedial grading recommendations Project Number 1-0572 Page 12
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presented herein, the potential for hydro-collapse shall be minimal and within foundation tolerances.

5.1.4 Expansion Potential
Based on expansion index testing performed during our subsurface investigation (Appendix C), the majority of soils onsite are “very low” to “low” in expansion potential (0≤EI≤50, Appendix C) when tested per ASTM D: 4829.

5.1.5 Earthwork Adjustments
The values presented in Table 5-1 are deemed appropriate for estimating purposes and may be used in an effort to balance earthwork quantities.

As is the case with every project, contingencies should be made to adjust the earthwork balance when grading is in-progress and actual conditions are better defined.

TABLE 5-1
Earthwork Adjustment Factors
Geologic Unit Adjustment Factor Range Average
Young Alluvium 15% to 19% 17%

5.1.6 Chemical Analyses
Chemical testing was performed on samples of material underlying the proposed site during our subsurface investigation. Soluble sulfate test results indicate that the soluble sulfate concentrations of the soils tested are classified as negligible (Category S0) per ACI 318-14.

Negligible chloride levels were detected in the soils onsite. Based on laboratory results of soluble sulfate, chloride, and pH testing as presented in Appendix C, the onsite soils are classified as “non-corrosive” Project Number 1-0572 Page 13
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(Caltrans, 2022). Additional discussions on corrosion are presented in Section 7.9.

5.2 Engineering Analysis
Presented below is a general discussion of the engineering analysis methods that were utilized to develop the conclusions and recommendations presented in this report.

5.2.1 Bearing Capacity and Lateral Earth Pressures
Ultimate bearing capacity values were obtained using the graphs and formula presented in NAVFAC DM-7.1. Allowable bearing was determined by applying a factor of safety of at least 3 to the ultimate bearing capacity. Static lateral earth pressures were calculated using Rankine methods for active and passive cases. If it is desired to use Coulomb forces, a separate analysis specific to the application can be conducted.

6.0 CONCLUSIONS AND RECOMMENDATIONS
Based on Alta’s findings during our subsurface investigation, the laboratory test results, our staff’s previous experience in the area, it is Alta’s opinion that the development of the site is feasible from a geotechnical perspective. Presented below are recommendations that should be incorporated into site development and construction plans.

6.1 Remedial Grading Recommendations

6.1.1 Site Preparation
Vegetation, construction debris, and other deleterious materials are unsuitable as structural fill material and should be disposed of offsite prior to commencing grading/construction. Any septic tanks, seepage pits or wells should be abandoned as per the County of San Diego Department of Health Services.

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Existing concrete should be removed prior to the placement of engineered fill. The demolished concrete may be incorporated into compacted, engineered fills after it is crushed to a maximum size of six (6) inches. Prior to placement as engineered fill any protruding steel rebar should be cut from the concrete pieces and disposed of offsite.

Existing asphaltic concrete should be removed prior to the placement of engineered fill. From a geotechnical perspective, this material may be incorporated into compacted, engineered fills after it is crushed to a maximum size of six (6) inches. The crushed asphalt should not be placed under residential structures, but rather, it can be placed in approved nonresidential areas, such as streets, parking areas or open space. These recommendations should be verified by the environmental consultant

6.1.2 Unsuitable Soil Removals
Due to the potential for loss of bearing and dynamic settlement due to liquefaction, mitigation strategies, including unsuitable soil removals are presented in Section 6.3.

The Project Geotechnical Consultant should observe the removal bottom prior to placing fill. If unsuitable soils such as undocumented artificial fill is exposed upon the completion of the removals recommended above, additional removals may be required.

For fill areas in streets, in general, a minimum removal and recompaction of the upper two (2) feet is recommended, however all undocumented artificial fill shall be removed and recompacted. For cuts greater than two (2) feet in street areas, removals are not required. For cuts less than two (2) feet, the two (2) foot removal and recompaction applies.

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Material removed as part of the unsuitable soil removals can be used as artificial fill, provided it is free of deleterious materials.

6.2 General Earthwork Recommendations

6.2.1 Compaction Standards
All fill and processed natural ground shall be compacted to a minimum relative compaction of 90 percent, as determined by ASTM Test Method:

D-1557. Fill material should be moisture conditioned to optimum moisture or above, and as generally discussed in Alta’s Earthwork Specification Section presented in Appendix F. Compaction shall be achieved with the use of sheepsfoot rollers or similar kneading type equipment. Mixing and moisture conditioning will be required in order to achieve the recommended moisture conditions.

6.2.2 Groundwater/Seepage
Depending on the depth of utilities, groundwater may be encountered during infrastructure construction. Utilizing gravel/crushed rock as backfill for utility lines below groundwater should be considered. Perched water conditions could also be encountered depending on the time of year construction occurs.

6.2.3 Documentation of Removals
All removal/over-excavation bottoms should be observed and approved by the project Geotechnical Consultant prior to fill placement.

Consideration should be given to surveying the removal bottoms and undercuts after approval by the geotechnical consultant and prior to the placement of fill. Staking should be provided in order to verify undercut locations and depths.

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6.2.4 Treatment of Removal Bottoms
At the completion of removals/over-excavation, the exposed removal bottom should be ripped to a minimum depth of eight (8) inches, moisture-conditioned to above optimum moisture content and compacted in-place to the project standards.

6.2.5 Fill Placement
After removals, scarification, and compaction of in-place materials are completed, additional fill may be placed. Fill should be placed in eightinch bulk maximum lifts, moisture conditioned to optimum moisture content or above, compacted and tested as grading/construction progresses until final grades are attained.

6.2.6 Moisture Content
The moisture content of the upper in-situ soils varies, as shown in the boring logs presented in Appendix B. The majority of onsite soils are below optimum in moisture content and will require moisture conditioning prior to placement as compacted fill.

6.2.7 Mixing
Mixing of materials may be necessary to prevent layering of different soil types and/or different moisture contents. The mixing should be accomplished prior to and as part of compaction of each fill lift.

6.2.8 Import Soils
Import soils, if necessary, should consist of clean, structural quality, low expansive, compactable materials similar to the on-site soils and should be free of trash, debris or other objectionable materials. The project Geotechnical Consultant should be notified not less than 72 hours in advance of the locations of any soils proposed for import. Import sources should be sampled, tested, and approved by the project Geotechnical Project Number 1-0572 Page 17
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Consultant at the source prior to the importation of the soils to the site.

The project Civil Engineer should include these requirements on plans and specifications for the project.

6.2.9 Utility Trenches

6.2.9.1 Excavation
Utility trenches should be supported, either by laying back excavations or shoring, in accordance with applicable OSHA standards. The existing site soils are classified as Soil Types "B" and "C" per OSHA standards. Upon completion of the
recommended removals and recompaction, the artificial fill will be classified as Soil Type “B”. The Project Geotechnical Consultant should be notified if geologic conditions vary from what is presented in this report.

6.2.9.2 Backfill
Trench backfill should be compacted to at least 90 percent of maximum dry density as determined by ASTM D-1557.

Onsite soils will not be suitable for use as bedding material but will be suitable for use in backfill provided oversized materials are removed. No surcharge loads should be
imposed above excavations. This includes spoil piles, lumber, concrete trucks, or other construction materials and
equipment. Drainage above excavations should be directed away from the banks. Care should be taken to avoid
saturation of the soils. Compaction should be accomplished by mechanical means. Jetting of native soils will not be acceptable.

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Under-slab trenches should also be compacted to project specifications. If select granular backfill (SE > 30) is used, compaction by flooding will be acceptable.

6.2.10 Backcut Stability
Temporary backcuts, if required during unsuitable soil removals, should be made no steeper than 1:1 without review and approval of the geotechnical consultant. Flatter backcuts may be necessary where geologic conditions dictate and where minimum width dimensions are to be maintained.

Care should be taken during remedial grading operations in order to minimize risk of failure. Should failure occur, complete removal of the disturbed material will be required.

In consideration of the inherent instability created by temporary construction backcuts for removals, it is imperative that grading schedules are coordinated to minimize the unsupported exposure time of these excavations. Once started, these excavations and subsequent fill operations should be maintained to completion without intervening delays imposed by avoidable circumstances. In cases where five-day workweeks comprise a normal schedule, grading should be planned to avoid exposing at-grade or near-grade excavations through a non-work weekend. Where improvements may be affected by temporary instability, either on or offsite, further restrictions such as slot cutting, extending workdays, implementing weekend schedules, and/or other requirements considered critical to serving specific circumstances may be imposed.

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6.3 Liquefaction
As presented in Section 4.5.4 of this report, there is potential for liquefaction to occur at the site during seismic shaking. More specifically, liquefaction could cause differential settlement. Typically, half to two thirds of that settlement should be considered differential (California Division of Mines and Geology, 2008, Special Publication 117a). If the analysis is based on multiple borings, seismic induced differential settlement may be determined as one-half the total settlement (City of Los Angeles, 2020). The maximum amount of settlement shown in Leighton’s 2024 analysis was approximately 7.1-inches.

Due to the potential for liquefaction to occur at the subject site, it is recommended that ground improvements be utilized below the proposed structures. A consultant who specializes in deep ground modification techniques for liquefaction should be used for the project. Ground improvements may include the use of rammed aggregate piers, deep soil mixing, compaction grouting, or other strategies the consultant recommends. The ground improvement techniques should be designed to reduce the potential for settlement for the proposed structures to levels acceptable as defined by the structural engineer, as well as reduce the potential for lateral spread. The intention of the proposed ground improvements is to reduce the effects of liquefaction to an acceptable level of risk. Note, some repairs may still be necessary if liquefaction occurs.

Improvements outside of the ground improvements shall be subject to the effects of liquefaction. These improvements include pavement, flatwork, utilities, and storm drain improvements. See Section 7.12 for additional recommendations
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6.4 Storm Water Infiltration Systems
From a geotechnical perspective, allowing storm water to infiltrate the onsite soil in concentrated areas increases the potential for settlement, liquefaction, and water-related damage to structures/improvements, such as wet slabs or pumping subgrade, and should be avoided where possible. If infiltration systems are required on this site, care should be taken in designing systems that control the storm water as much as possible.

Infiltration testing was undertaken within the area of the proposed basin as presented in Plate 1. The testing resulted in infiltration rates of 15.6 and 12.3 inches per hour for P-1 and P-2, respectively. The Project Geotechnical Consultant should review the WQMP plans and observe the WQMP excavations during construction to verify that the infiltration rates presented herein are appropriate.

6.5 Boundary Conditions
Construction of retaining/screen walls along site boundaries may require additional geotechnical recommendations concerning unsuitable soil removals and foundation design parameters. Boundary conditions for the project should be reviewed by the Project Geotechnical Consultant as the design progresses.

7.0 DESIGN CONSIDERATIONS

7.1 Structural Design
It is anticipated that multi-story wood-framed residential structures with slab ongrade and shallow foundations will be constructed. Upon the completion of rough grading, finish grade samples should be collected and tested in order to provide specific recommendations as they relate to the individual building pads.

These test results and corresponding design recommendations should be presented in a final rough grading report. Final slab and foundation design Project Number 1-0572 Page 21
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recommendations should be made based upon specific structure sitings, loading conditions, and as-graded soil conditions.

It is anticipated that the majority of onsite soils will possess “very low” to “low” expansion potential when tested in general accordance with ASTM Test Method D: 4829.

The following foundation design requirements are presented with the assumption that ground improvement designs, as prepared by a consultant who specialized in deep ground modification techniques, reduces the potential for dynamic settlement and lateral spreading to levels within foundation tolerances.

7.1.1 Foundation Design
Foundations may be preliminary designed based on the values presented in Table 7-1 below.

Table 7-1
Foundation Design Parameters*
Allowable Bearing 2000 lbs/ft2 (assuming a minimum embedment depth and width of 12 inches)
Lateral Bearing 250 lbs/ft2 at a depth of 12 inches plus 250 lbs/ft2 for each additional 12 inches of embedment to a maximum of 2000
lbs/ft2
.

Sliding Coefficient 0.30
Settlement Static Settlement – 0.5 inch in 40 feet
Dynamic Settlement – 1.5 inch in 40 feet
*These values may be increased as allowed by Code to resist transient loads such as wind or seismic. Building code and structural design considerations may govern depth and reinforcement requirements and should be evaluated.

7.1.2 Post-Tensioned Slabs/Foundation Design Recommendations Post-tensioned slabs for the project may be designed utilizing the parameters presented in Tables 7-1 and 7-2. The parameters presented herein are based on methodology provided in the Design of PostTensioned Slabs-On-Ground, Third Edition, by the Post-Tensioning Institute, in accordance with the 2022 CBC.

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TABLE 7-2

POST-TENSION SLAB DESIGN PARAMETERS
Category Expansion Potential Minimum
Embedment*
Edge Lift Center Lift
Em (ft) Ym
(inch) Em (ft) Ym (inch)
I Very Low to Low 12 inches 5.4 0.61 9.0 0.26
Slab Subgrade Moisture
Category I Minimum 110% of optimum moisture to a depth of 12 inches prior to pouring concrete
Embedment*
The minimum footing embedments presented herein are based on expansion indexes. The structural engineer should determine minimum embedments based on the number of floors supported by the footings, the structural loading, and the requirements of the latest California Building Code. If mat slabs are utilized, alternate embedment depths can be provided.

Moisture Barrier
A moisture barrier should be provided in accordance with the recommendations presented in Section 7.2 The parameters presented herein are based on procedures presented in the Design of Post-Tensioned Slabs-OnGround, Third Edition. No corrections for vertical barriers at the edge of the slab, or for adjacent vegetation have been assumed. The design parameters are based on a Constant Suction Value of 3.9 pF.

7.2 Moisture Barrier
A moisture and vapor retarding system should be placed below the slabs-ongrade in portions of the structure considered to be moisture sensitive and should be capable of effectively preventing the migration of water and reducing the transmission of water vapor to acceptable levels. Historically, a 10-mil plastic membrane, such as Visqueen, placed between two to four inches of clean sand, has been used for this purpose. The use of this system or other systems can be considered, at the discretion of the designer, provided the system reduces the vapor transmission rates to acceptable levels.

7.3 Seismic Design
The site classes were determined based on the referenced reports and published geologic maps in the area in general conformance with Chapter 20 of ASCE 7-16.

Based on the density of the underlying soils, a Site Class of D (shear wave velocity of 259 m/s) was selected. The seismic design parameters were calculated using a program based on the USGS website and ASCE 7-16 Project Number 1-0572 Page 23
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procedures. The resulting values are presented in Table 7-3. These values are applicable providing the exceptions presented in Supplements 2 and 3 of ASCE 7- 16 are utilized in the design of the structure. If the design does not include the exception methodology, then a site-specific analysis shall be conducted.

TABLE 7-3 Seismic Ground Motion Values
2022 CBC and ASCE 7-16
Parameter Value
Site Class D
Site Latitude 32.8484
Site Longitude -116.9755
Spectral Response Acceleration Parameter, SS 0.769
Spectral Response Acceleration Parameter, S1 0.283
Site Coefficient, Fa 1.192
Site Coefficient, Fv 2.0
MCE Spectral Response Acceleration Parameter, SMS 0.917 MCE Spectral Response Acceleration Parameter, SM1 0.566 Design Spectral Response Acceleration Parameter, SDS 0.612 Design Spectral Response Acceleration Parameter, SD1 0.377 Peak Ground Acceleration, PGAM 0.419

7.4 Block Walls
Block walls, if used, should be embedded a minimum of 2 feet below the lowest adjacent grade. Construction joints (not more than 20 feet apart) should be included in the block wall construction. Side yard walls should be structurally separated from the rear yard wall.

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ALTA CALIFORNIA GEOTECHNICAL, INC.

7.5 Footing Excavations
Soils from the footing excavations should not be placed in slab-on-grade areas unless properly compacted and tested. The excavations should be cleaned of all loose/sloughed materials and be neatly trimmed at the time of concrete placement.

7.6 Retaining Wall Design
Retaining walls should be founded on compacted fill and should be backfilled with granular soils that allow for drainage behind the wall. Foundations may be designed in accordance with the recommendations presented in Table 7-1, above. Unrestrained walls, free to rotate at least 0.001 radians, may be designed to resist lateral pressures imposed by a fluid with a unit weight determined in accordance with the Table 7-4 below. The table also presents design parameters for restrained retaining walls. These parameters may be used to design retaining walls that may be considered as restrained due to the method of construction or location (corner sections of unrestrained retaining walls).

TABLE 7-4
Equivalent Fluid Pressures for 90% Compacted Fill
Backfill Active Pressure (psf/ft) At-Rest Pressure (psf/ft) Level 35 55
Per the requirements of the CBC, the seismic force acting on the retaining walls with backfill exceeding 6-feet in height may be resolved utilizing the formula

8.5H2 lb/lineal ft (H=height of the wall). This force acts at approximately 0.6H above the base of the wall (inverted triangle). The seismic value can be converted as required by the retaining wall engineer. Retaining walls should be designed in general accordance with Section 1807A.2 of the 2022 CBC.

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ALTA CALIFORNIA GEOTECHNICAL, INC.
 Restrained retaining walls should be designed for “at-rest” conditions, utilizing at-rest pressure.
 The design loads presented in the above table are to be applied on the retaining wall in a horizontal fashion and as such friction between wall and retained soils should not be allowed in the retaining wall analyses.  Additional allowances should be made in the retaining wall design to account for the influence of construction loads, temporary loads, and possible nearby structural footing loads.
 Select backfill should be granular, structural quality backfill with a Sand Equivalent of 20 or better and an ASCE Expansion Index of 20 or less. The backfill must encompass the full active wedge area. The upper one foot of backfill should be comprised of native on-site soils (see Plate A).  The wall design should include waterproofing (where appropriate) and backdrains or weep holes for relieving possible hydrostatic pressures. The backdrain should be comprised of a 4-inch perforated PVC pipe in a 1 ft. by 1 ft., ¾-inch gravel matrix, wrapped with a geofabric. The backdrain should be installed with a minimum gradient of 2 percent and should be outletted to an appropriate location.
 No backfill should be placed against concrete until minimum design strengths are achieved.

It should be noted that the allowable bearing and lateral bearing values presented in Table 7-1 are based on level conditions at the toe. Modified design parameters can be presented for retaining walls with sloping condition at the toe.

Other conditions should be evaluated on a case-by-case basis.

7.7 Exterior Slabs and Walkways
Exterior concrete slabs and walkways should be designed and constructed in consideration of the following recommendations.

7.7.1 Subgrade Compaction
The subgrade below exterior concrete slabs should be compacted to a minimum of 90 percent relative compaction as determined by ASTM Test Method: D 1557.

RETAINING WALL BACKFILL DETAIL
NATIVE

BACKFILL
12 tN. MtN.
*OR AS MODIFIED

BY A SPECIFIC REPORT
DRAIN I.ATERALLY,

OR PROVIDE WEEP

HOLES AS REQUIRED

TO DMIN
PIPE: 4-INCH PERFORATED PVC, SCHEDULE 40, SDR35 OR APPROVED ALTERNATE MINIMUM 8 PERFORATIONS (1/4-IN. DIA.) PER LINEAL FT. IN BOTTOM HALF OF PIPE
ROCK: MINIMUM VOLUME OF 1 CU. FT. OF 3/4_IN. MAX. ROCK PER. LINEAL FOOT

OF PIPE, OR APPROVED ALTERNATE
FILTER FABRIC: MIRAFI 140 FILTER FABRIC OR APPROVED EQUIVALENT "64
ALTA cALTFoRNTA eEorEcl{NrcAL, tNc,
'vER, tTto PI-ATE A
PATH: S\Drofllns\ALTA GEoTECHNICAI\GRAoING DETAIIS\PLATE A.dws Project Number 1-0572 Page 26
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

7.7.2 Subgrade Moisture
The subgrade below concrete slabs should be moisture conditioned to a minimum of 110 percent of optimum moisture content prior to concrete placement.

7.7.3 Concrete Slab Thickness
Concrete flatwork and driveways should be designed utilizing four-inch minimum thickness.

7.7.4 Concrete Slab Reinforcement
Utilization of reinforcement for flatwork and driveways is subject to a cost/benefit analysis for the developer. Reinforcement will decrease the amount of cracking that may occur in flatwork, however, planning for occasional repairs may be more cost effective. The majority of the soils onsite are classified as very low in expansion potential. Consideration should be given to reinforcing flatwork with irregular (nonsquare/rectangular) shapes.

7.7.5 Control Joints
Weakened plane joints should be installed on walkways at intervals of approximately eight feet. Exterior slabs should be designed to withstand shrinkage of the concrete.

7.8 Concrete Design
As stated in Section 5.1.6, negligible concentrations of sulfates were detected in the onsite soils. Therefore, the use of sulfate resistant concrete is not required per ACI 318-14 at this time. Post-grading conditions should be evaluated, and final recommendations made at that time.

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ALTA CALIFORNIA GEOTECHNICAL, INC.

7.9 Corrosion
Based on preliminary testing from our investigation and the previous investigation, the onsite soils are classified as “non-corrosive” (Caltrans, 2022).

Consideration should be given to protecting buried metals from corrosion.

Typical measures may include using non-corrosive backfill, protective coatings, wrapping, plastic pipes, or a combination of these methods. A corrosion engineer should be consulted if specific design recommendations are required by the improvement designer.

Per ACI 318-14, an exposure class of C1 would be applicable to metals encased in concrete (rebar in footings) due to being exposed to moisture from surrounding soils. Per Table 19.3.2.1 of ACI 318-14, the requirements for concrete with an exposure class of C1 are a minimum compressive strength of 2500 psi and a maximum water-soluble chloride ion content in concrete of 0.30 (percent by weight of cement).

7.10 Pavement Design
Pavement sections for the proposed streets shall be designed based on laboratory testing conducted on samples taken from the soil subgrade.

Preliminarily, based on an assumed R-Value of 30, the pavement may be designed utilizing the sections presented in Table 7-5. These sections should be verified upon the completion of grading, based on R-Value testing. The ultimate pavement section design for public streets is under the City of Santee’s purview.

Table 7-5
Preliminary Pavement Sections
Traffic
Index
Pavement Section Options
OR

5.0 3-inch AC on 6-inch AB 4-inch AC on 4-inch AB

5.5 3-inch AC on 7-inch AB 4-inch AC on 5-inch AB

6.0 3.5-inch AC on 7.5-inch AB 4-inch AC on 6.5-inch AB AC-Asphalt Concrete
AB-Caltrans Class II Base
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ALTA CALIFORNIA GEOTECHNICAL, INC.

Construction of the streets should be accomplished in accordance with the current criteria of the City of Santee. Prior to the placement of base material, the subgrade should be suitably moisture conditioned, processed and compacted to a minimum 95 percent of the laboratory maximum density (ASTM:

D 1557) to at least twelve (12) inches below subgrade. After subgrade compaction, the exposed grade should then be "proof"-rolled with heavy equipment to ensure the grade does not "pump" and is verified as non-yielding.

Aggregate base material should be placed on the compacted subgrade and compacted in-place to a minimum 95 percent of the laboratory standard obtained per ASTM: D 1557.

7.11 Site Drainage
Positive drainage away from the proposed structures should be provided and maintained. Roof, pad, and lot drainage should be collected and directed away from the structures toward approved disposal areas through drainage terraces, gutters, down drains, and other devices. Design fine grade elevations should be maintained through the life of the structure or if design fine grade elevations are altered, adequate area drains should be installed in order to provide rapid discharge of water, away from structures.

7.12 Utility Design
As discussed in Section 6.3, areas outside of the rammed aggregate piers shall be subject to the effects of liquefaction. Repairs shall be required if liquefaction occurs. Utility lines should include automatic shut-off valves and flexible connections where possible.

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ALTA CALIFORNIA GEOTECHNICAL, INC.

8.0 LOT MAINTENANCE
Ongoing maintenance of the improvements is essential to the long-term performance of structures and slopes. As such, the owners must implement certain maintenance procedures. The attached "Maintenance and Improvement Considerations" presented in the Appendix D should be reviewed for issues related to drainage, slopes, maintenance, backyard improvements, etc. The following recommendations should also be implemented.

8.1 Lot Drainage
Roof, pad and lot drainage should be collected and directed away from structures and slopes and toward approved disposal areas. Design fine grade elevations should be maintained through the life of the structure or if design fine grade elevations are altered, adequate area drains should be installed in order to provide rapid discharge of water, away from structures and slopes. Residents should be made aware that they are responsible for maintenance and cleaning of all drainage terraces, down drains, and other devices that have been installed to promote structure and slope stability.

8.2 Burrowing Animals
Residents or owners should undertake a program for the elimination of burrowing animals. This should be an ongoing program in order to maintain slope stability.

9.0 FUTURE PLAN REVIEWS
This report represents a geotechnical review of the tract map. As the project design progresses, site specific geologic and geotechnical issues need to be considered in the design and construction of the project. Consequently, future plan reviews may be necessary. These reviews may include reviews of:
 Grading Plans
 Foundation plans
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ALTA CALIFORNIA GEOTECHNICAL, INC.
 Utility Plans
These plans should be forwarded to the Project Geotechnical Consultant for review.

10.0 CLOSURE

10.1 Geotechnical Review
For the purposes of this report, multiple working hypotheses were established for the project, utilizing the available data and the most probable model is used for the analysis. Future information collected during the proposed grading operations is intended to evaluate the hypothesis and as such, some of the assumptions summarized in this report may need to be changed. Some modifications of the grading recommendations may become necessary, should the conditions encountered in the field differ from the conditions hypothesized in this report.

Plans and sections of the project specifications should be reviewed by Alta, to evaluate conformance with the intent of the recommendations contained in this report. If the project description or final design varies from that described in herein, Alta must be consulted regarding the applicability of the recommendations contained herein and whether any changes are required. Alta accepts no liability for any use of its recommendations if the project description or final design varies and Alta is not consulted regarding the alterations.

10.2 Limitations
This report is based on the following: 1) the project as presented on the attached plan; 2) the information obtained from the subsurface investigation at the approximate locations indicated on the plans included herein; and 3) from the information presented in the referenced reports. The findings and recommendations are based on the results of the subsurface investigation, laboratory testing, and office analysis combined with an interpolation and Project Number 1-0572 Page 31
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.
extrapolation of conditions between and beyond the subsurface excavation locations. However, the materials adjacent to or beneath those observed may have different characteristics than those observed, and no precise representations are made as to the quality or extent of the materials not observed. The results reflect an interpretation of the direct evidence obtained.

Work performed by Alta has been conducted in a manner consistent with the level of care and skill ordinarily exercised by members of the geotechnical profession currently practicing in the same locality under similar conditions. No other representation, either expressed or implied, and no warranty or guarantee is included or intended.

The recommendations presented in this report are based on the assumption that an appropriate level of field review will be provided by a geotechnical consultant who is familiar with the design and site geologic conditions. That field review shall be sufficient to confirm that geotechnical and geologic conditions exposed during grading are consistent with the geologic representations and corresponding recommendations presented in this report.

The conclusions and recommendations included in this report are applicable to the specific design of this project as discussed in this report. They have no applicability to any other project or to any other location and any and all subsequent users accept any and all liability resulting from any use or reuse of the data, opinions, and recommendations without the prior written consent of Alta.

Alta has no responsibility for construction means, methods, techniques, sequences, procedures, safety precautions, programs in connection with the construction, acts or omissions of the CONTRACTOR or any other person Project Number 1-0572 Page 32
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.
performing any of the construction, or for the failure of any of them to carry out the construction in accordance with the final design drawings and specifications

APPENDIX A

REFERENCES
Project Number 1-0572 Page A-1
January 29, 2025

APPENDIX A
Selected References
California Code of Regulations, 2022, California Building Code, Title 24, Part 2, Volume 2, Based on the 2021 International Building Code, Effective Date January 1, 2023.

California Department of Transportation (Caltrans), 2022, Caltrans Geotechnical Manual, published March, 2022.

California Department of Water Resources, Water Data Library, 2025, Website, http://www.wdl.water.ca.gove/waterdatalibrary/
California Division of Mines and Geology, 2008, Guidelines for evaluating and mitigating seismic hazards in California: Department of Conservation, Special Publication 117a.

California Geological Survey, 1999, Earthquake Fault Zones, A Guide for Government Agencies, Property Owners/Developers, And Geoscience Practitioners for Assessing Fault Rupture Hazards in California, Special Publication 42, Revised 1999.

Tan, S.S., 2002, Geologic map of the El Cajon 7.5-minute quadrangle, San Diego County, California: A digital database., California Geological Survey, Preliminary Geologic Maps PGM-02-06, map scale 1:24,000.

Law Crandall, 1999, Report of Preliminary Geotechnical Investigation for Rough Grading, Proposed Santee Town Center Edgemoor Property, Santee, California, dated May 7, 1999.

Leighton and Associates, 2024, Preliminary Geotechnical Investigation, Santee 3 Development, APN: 181-051-018, Santee, California, dated February 5, 2024 (Project No. 11832.002) Historical Aerials.com, 2025, online vertical and color aerials photographs from 1953 – 2022, accessed January 2025, http://www.historicaerials.com/.

Jennings, C.W., and Bryant, W.A., 2010, Fault Activity Map of California: California Geological Survey Geologic Data Map No. 6, map scale 1:750,000.

Jennings, C. W., and Bryant, W. A., 2021, An explanatory test to accompany the Fault Activity Map of California: California Department of Conservation, California Geological Survey.

Jennings, C. W., 1985, An explanatory text to accompany the 1:750,000 scale fault and geologic map of California: California Division of Mines and Geology, Bulletin 201, 197p.

Romanoff, Melvin, 1989, Underground Corrosion, NBS Circular 579, Reprinted by NACE, Houston, TX, 1989.

U.S. Geological Survey, 2008, National Seismic Hazards Maps – Source Parameters, http://geohazards.usgs.gov/cfusion/hazfaults_2008_search/query_main.cfm.

APPENDIX B
Subsurface Investigation
Project No. 1-0572 Page B-1
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX B
Subsurface Investigation
Alta's subsurface investigation consisted of excavating, logging, and sampling five (5) hollowstem auger borings. Details of the subsurface investigation are presented in Table B-1. The approximate locations of the exploratory excavations are shown on the accompanying Plate 1 and the Geotechnical Logs are attached.

TABLE B-1

SURFACE INVESTIGATION DETAILS
Equipment Range of
Depths
Sampling Methods Sample Locations
8” HollowStem Auger Up to 47.0
feet

1. Bulk Samples

2. Ring Samples

3. SPT Samples

1. Bulk-Select Depths

2. Ring-Every 2.5 or 5.0 feet.

3. SPT-At depths below 30 feet.

UNIFIED SOI L CLASSIFIICATION SYSTEM
Major Divisions lfl tr Description Major Divisions an tr Coarse
Grained
Soils
N4ore than
50%
retained on
No 200
steve
Gravel
and
Sravelly
Soils
han 50%
frachon
relained
on No, 4
'l
ts
*
,-l*
EIF
GW
Well-graded grcvels or gravel sand
mixtures, little or no fines
Fine
(lrained
isoils
l\lore than
Silts
And
Clays
LL,<50
n
ML
Inorganic silts and very fine sands,
rock flour, silty or clayey fine sands
or clavev silts with slioht olasticitv
GP
Poorly-graded gravels or gravel
sand mixture, little or no fines CL
Inorganic clays of low to medium
plasticity, gravelly clays, sandy
clays, silty clays, lean clays Silty gravels, gravel-sand-silt mixtures
OL
Organic silts and organic silt-clays
of low plasticity
Clayey gravels, gravel-sand-clay
mixtures
Silts
And
Clays
LL,<50
MF
Inorganic silts, micaceous or
diatomaceous fine or silty soils,
elastic silts Sand
and
Sandy
Soils
than 50%
fraclion
Passes
on No, 4
i'+.
3_'. JV!
Well-graded sands or gravelly
sands, little or no fines
on No 200
steve VH
Inorganic clays of high plasticity,
fat clays SP
Poorly-graded sands or gravelly
sands, little or no fines
SM Silty sands, sarrd-silt mixtures OF
Organic clays of medium to high
plasticity
sc Clayey sands, and-clay mixtures Highly Organic
Soils PT Peat and other highly organic soils
BoUNDARY CLASSIFICATIoN: Soils possessing characteristics of two groups are designated by combinations of group symbols PARTICLE SIZ:E LIMITS
U.S. STANDA,RD SiERIES SIEVE
200 40 10 4

CLEAR SQUARE SIEVE OPENINGS
3t4" 3,, ,t2"

LABORATORY TESTS
Symbol Tesl
DS
DSR
cc)N
SA
MAX
RV
EI
SE
AL
CHEM
HY
Direct Shear
Direct Shear
(Remolded)
Sieve Analysis
Maximum Density
Resistance (R) Value
Expansion Index
Sand Equivalent
Atterberg Limits
Chemical Analysis
Hydrometer Analysis

SOIL MOISTURE

SIZE PROPORTIONS
Trace - <5%
Few-5to10%
Some - 15 to 25%
Increasing \/isual Moisture Content
Silts
an0
Clays
Sand Gravel
Cobbles Boulders
Fine Medium Coarsi€r Fine Coarse

RELATIVE DENSITY
Sands and Gravels Blows/Foot (SPT)
Very Loose
Loose
Medium Dense
Dense
Very Dense
<4
4-10
11-30
31 -50
>50

CON SI STENCY C IASSI FI CATI ON
Silts and Clays Criteria
Very Soft
Soft
Firm
stiff
Very Stiff
Thumb penetrates soil >1 in.

Thumb penetrates soil 1 in,
Thumb penetrates soil 1/4 in
Readily indented with thumbnail
Thumbnail will not indent soil

HARDNESS
KEY TO EXPLORATORY BORING LOGS}
,n
/L>//J, ALTA CALIFORNTA GEOTECHNTCAL tNC.
/\

PI-ATE B
SW
SP
SM
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, very fine to fine grained, gray, slightly moist, medium dense, trace silt, micaceous.
@5.0 ft. some iron oxide, some silt.
@10.0 ft. fine to medium grained.
@15.0 ft. wet, with roots, trace clay.
@18.7 ft. groundwater encountered.
@20.0 ft. SILTY SAND, very fine to fine grained, dark gray, wet, medium dense, with roots, micaceous.
@25.0 ft. dense.

TOTAL DEPTH 26.0 FEET
GROUNDWATER AT 18.7 FEET

NO CAVING OBSERVED
R
R
R
R
R
R
14 21
16 14
14 41
11 4
22 78
91 CON
94 96
90 98
87 3.3

1.1 6.8

20.3 30.6

11.4 140 lbs
Cottonwood & Park Center
1 OF 1
30 in
B-1
19 341
5 10
15 20
25 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
340
335
330
325
320
315

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-1
SM
SP
SM
SP
SM
SP
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, very fine to fine grained, brownish gray, dry, medium dense, micaceous.
@5.0 ft. fine to medium grained.
@10.0 ft. moist.
@14.7 ft. groundwater encountered.
@15.0 ft. SILTY SAND, fine grained, dark gray, wet, medium dense, trace clay, micaceous.
@20.0 ft. fine to medium grained, some clay.
@25.0 ft. fine grained.
@30.0 ft. SAND, fine to medium grained, dark gray, wet, medium dense.
@31.0 ft. SILTY SAND, fine grained, dark gray, wet, medium dense. @35.0 ft. SAND, fine to medium grained, dark gray, wet, very dense, some gravel.

R
R
R
R
R
R
S
S
13 14
16 17
18 16
3,4,9
36,50 for
3"
7 76
86 87
MAX,
EI,
HY,
CHEM
96 101
104
92 1.9

1.2 18.5

19.3 26.3

18.6 11.6

21.1 140 lbs
Cottonwood & Park Center
1 OF 2
30 in
B-2
15 341
5 10
15 20
25 30
35 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
340
335
330
325
320
315
310
305

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-2
SC
SP
@40.0 ft. CLAYEY SAND, fine grained, yellowish gray, slightly moist, hard.
@45.0 ft. SAND, fine to coarse grained, dark gray to gray, slightly moist, very dense, some gravel.

TOTAL DEPTH 47.0 FEET; REFUSAL AT 47.0 FEET
GROUNDWATER AT 14.7 FEET

NO CAVING OBSERVED
S
S
15,17,23
13,30,50
for 5"

10.1 140 lbs
Cottonwood & Park Center
2 OF 2
30 in
B-2
15 341
45 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
300
295

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-2
SM
SP
SM
SP
SM
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, fine to medium grained, brownish gray, slightly moist, medium dense, trace silt.
@5.0 ft. SILTY SAND, fine grained, dark gray, slightly moist, medium dense.
@10.0 ft. SAND, fine grained, gray, slightly moist, medium dense. @15.0 ft. medium to coarse grained, brownish gray, moist. @16.8 ft. groundwater encountered.
@20.0 ft. wet, dense, trace silt.
@25.0 ft. SILTY SAND, fine to coarse grained, brownish dark gray, wet, medium dense.

TOTAL DEPTH 26.0 FEET
GROUNDWATER AT 16.8 FEET

NO CAVING OBSERVED
R
R
R
R
R
R
12 15
14 16
37 28
17 15
22 33
65 CON,
HY
93 96
91 93
103

5.0 4.2

6.9 9.5

14.7 15.1
140 lbs
Cottonwood & Park Center
1 OF 1
30 in
B-3
17 344
5 10
15 20
25 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
340
335
330
325
320

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-3
SM
SP
CL
SP
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 SAND, fine grained, brownish gray, slightly moist, medium dense.
@5.0 ft. trace silt, micaceous.
@10.0 ft. fine to coarse grained, gray, slightly moist, medium dense. @15.0 ft. brownish gray, wet.
@16.2 ft. groundwater encountered.
@25.0 ft. SILTY CLAY, brown, wet, firm.
@35.0 ft. SAND, coarse grained, brownish gray, slightly moist, very dense.

TOTAL DEPTH 36.0 FEET; REFUSAL AT 36.0 FEET
GROUNDWATER AT 16.2 FEET

NO CAVING OBSERVED
R
R
R
R
R
R
S
S
S
13 18
27 18
27 15
3,7,12
50 for 1"
50 for 4"
22 9
11 60
83 MAX,
EI,
HY,
CHEM
104
89 94
94 91

4.9 3.0

3.1 17.2

11.1 26.0

23.3 22.6

13.4 140 lbs
Cottonwood & Park Center
1 OF 1
30 in
B-4
16 344
5 10
15 20
25 30
35 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
340
335
330
325
320
315
310

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-4
SM
SP
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, very fine to fine grained, gray, slightly moist, medium dense, trace silt, micaceous.
@5.0 ft. some iron oxide, trace silt.

TOTAL DEPTH 10.0 FEET

NO GROUNDWATER ENCOUNTERED

NO CAVING OBSERVED
Cottonwood & Park Center
1 OF 1
339 P-1
5 10

TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
335
330

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-5
SM
SP
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, very fine to fine grained, brownish gray, slightly moist, medium dense, trace silt, micaceous.

TOTAL DEPTH 5.0 FEET

NO GROUNDWATER ENCOUNTERED

NO CAVING OBSERVED
Cottonwood & Park Center
1 OF 1
339 P-2
5 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
335

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-6
APPENDIX B-1
Previous Subsurface Data (Leighton, 2024)

SUMMARY
OF

CONE PENETRATION TEST DATA
Prepared by:
5415 Industrial Drive
Huntington Beach, CA 92649-1518
Office (714) 901-7270 / Fax (714) 901-7289
www.kehoetesting.com
Project:

City Ventures Santee 3 Geoinv
Cottonwood Avenue & Claudia Avenue
Santee, CA
April 24, 2023
Prepared for:

Mr. Nick Tracy
Leighton & Associates
3934 Murphy Canyon Road, B205
San Diego, CA 92123-4425
Office (800) 447-2626 / Fax (858) 292-0771

TABLE OF CONTENTS

1. INTRODUCTION

2. SUMMARY OF FIELD WORK

3. FIELD EQUIPMENT & PROCEDURES

4. CONE PENETRATION TEST DATA & INTERPRETATION

APPENDIX
CPT Plots
CPT Classification/Soil Behavior Chart
CPT Data Files (sent via email)

SUMMARY
OF

CONE PENETRATION TEST DATA

1. INTRODUCTION
This report presents the results of a Cone Penetration Test (CPT) program carried out for the City Ventures Santee 3 Geoinv project located at Cottonwood Avenue & Claudia Avenue in Santee, California. The work was performed by Kehoe Testing & Engineering (KTE) on April 24, 2023. The scope of work was performed as directed by Leighton & Associates personnel.

2. SUMMARY OF FIELD WORK
The fieldwork consisted of performing CPT soundings at six locations to determine the soil lithology. A summary is provided in TABLE 2.1. LOCATION

DEPTH OF
CPT (ft) COMMENTS/NOTES:

CPT-8 46 Refusal
CPT-9 47 Refusal
CPT-10 38 Refusal
CPT-11 36 Refusal
CPT-12 38 Refusal
CPT-13 50
TABLE 2.1 - Summary of CPT Soundings

3. FIELD EQUIPMENT & PROCEDURES
The CPT soundings were carried out by KTE using an integrated electronic cone system manufactured by Vertek. The CPT soundings were performed in accordance with ASTM standards (D5778). The cone penetrometers were pushed using a 30-ton CPT rig. The cone used during the program was a 15 cm^2 cone with a cone net area ratio of 0.83. The following parameters were recorded at approximately 2.5 cm depth intervals:

Cone Resistance (qc) Inclination
Sleeve Friction (fs) Penetration Speed
Dynamic Pore Pressure (u)
The above parameters were recorded and viewed in real time using a laptop computer. Data is stored at the KTE office for up to 2 years for future analysis and reference. A complete set of baseline readings was taken prior to each sounding to determine temperature shifts and any zero load offsets. Monitoring base line readings ensures that the cone electronics are operating properly.

4. CONE PENETRATION TEST DATA & INTERPRETATION
The Cone Penetration Test data is presented in graphical form in the attached Appendix. These plots were generated using the CPeT-IT program. Penetration depths are referenced to ground surface. The soil behavior type on the CPT plots is derived from the attached CPT SBT plot (Robertson 2009) and presents major soil lithologic
changes. The stratigraphic interpretation is based on relationships between cone resistance (qc), sleeve friction (fs), and penetration pore pressure (u). The friction ratio (Rf), which is sleeve friction divided by cone resistance, is a calculated parameter that is used along with cone resistance to infer soil behavior type. Generally, cohesive soils (clays) have high friction ratios, low cone resistance and generate excess pore water pressures. Cohesionless soils (sands) have lower friction ratios, high cone bearing and generate little (or negative) excess pore water pressures.

The CPT data files have also been provided. These files can be imported in CPeT-IT (software by GeoLogismiki) and other programs to calculate various geotechnical parameters.

It should be noted that it is not always possible to clearly identify a soil type based on qc, fs and u. In these situations, experience, judgement and an assessment of the pore pressure data should be used to infer the soil behavior type.

If you have any questions regarding this information, please do not hesitate to call our office at (714) 901-7270.

Sincerely,
Steven P. Kehoe
President
04/27/23-aga-5234

APPENDIX

ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX B-2
Previous Subsurface Data (Leighton, 2017)

GREGG DRILLING & TESTING, INC.

GEOTECHNICAL AND ENVIRONMENTAL INVESTIGATION SERVICES
2726 Walnut Ave. Signal Hill, California 90755 (562) 427-6899 FAX (562) 427-3314 www.greggdrilling.com
10/27/17
Leighton and Associates
Attn: Mike Jensen
Subject: CPT Site Investigation
City Ventures/Santee B
Santee, California
GREGG Project Number: 17-638SH
Dear Mr. Jensen:

The following report presents the results of GREGG Drilling & Testing Test investigation for the above referenced site. The following testing services were performed:
1 Cone Penetration Tests (CPTU)
2 Pore Pressure Dissipation Tests (PPD)
3 Seismic Cone Penetration Tests (SCPTU)
4 UVOST Laser Induced Fluorescence (UVOST)
5 Groundwater Sampling (GWS)
6 Soil Sampling (SS)
7 Vapor Sampling (VS)
8 Pressuremeter Testing (PMT)
9 Vane Shear Testing (VST)
10 Dilatometer Testing (DMT)
A list of reference papers providing additional background on the specific tests conducted is provided in the bibliography following the text of the report. If you would like a copy of any of these publications or should you have any questions or comments regarding the contents of this report, please do not hesitate to contact our office at (562) 427-6899.

Sincerely,
GREGG Drilling & Testing, Inc.

Frank Stolfi
HRSC Division Manager, Gregg Drilling & Testing, Inc.

GREGG DRILLING & TESTING, INC.

GEOTECHNICAL AND ENVIRONMENTAL INVESTIGATION SERVICES
2726 Walnut Ave. Signal Hill, California 90755 (562) 427-6899 FAX (562) 427-3314 www.greggdrilling.com
Cone Penetration Test Sounding Summary
-Table 1-
CPT Sounding
Identification
Date Termination
Depth (feet)
Depth of Groundwater
Samples (feet)
Depth of Soil
Samples (feet)
Depth of Pore
Pressure Dissipation
Tests (feet)
CPT-1 10/26/17 43 - - -
CPT-2 10/26/17 43 - - -
CPT-3 10/26/17 46 - - -
CPT-4 10/26/17 51 - - -
CPT-5 10/26/17 46 - - -
CPT-6 10/26/17 25 - - -
CPT-7 10/26/17 32 - - -
GREGG DRILLING & TESTING, INC.

GEOTECHNICAL AND ENVIRONMENTAL INVESTIGATION SERVICES
2726 Walnut Ave. Signal Hill, California 90755 (562) 427-6899 FAX (562) 427-3314 www.greggdrilling.com
Bibliography
E & FN Spon. ISBN 0 419 23750, 1997
1990 pp. 151-158.
through www.ce.gatech.edu/~geosys/Faculty/Mayne/papers/index.html, Section 5.3, pp. 107-112.

Robertson, P.K., R.G. Campanella, D. - Journal of Geotechnical Engineering ASCE, Vol. 112, No. 8, 1986 pp. 791-803.

Robertson, P.K., Sully, J., Woeller, D.J., Lunne, T., Powell, J.J.M., and Gillespie, D.J., "Guidelines for Estimating Consolidation Parameters in Soils from Piezocone Tests", Canadian Geotechnical Journal, Vol. 29, No. 4, August 1992, pp. 539-550. - Geotechnical
Site Characterization, Robertson & Mayne (editors), 1998 Balkema, Rotterdam, ISBN 90 5410 939 4 pp 35-47.

Geotechnical Journal, Vol. 27 No. 5, 1990 pp. 557-567.

Site Characterization Conference - Atlanta, 1998.

Woeller, D.J., P.K. Robertson,
Using the UVIF- rd Canadian Geotechnical Conference Montreal, QC October pp. 733-739, 2000. d Comparison of Analytical Results from
DiscreteConference, Las Vegas, Nevada Proceedings, 1992, pp 299-312.

Copies of ASTM Standards are available through www.astm.org Revised 02/05/2015 i
Cone Penetration Testing Procedure (CPT)
Gregg Drilling carries out all Cone Penetration Tests
(CPT) using an integrated electronic cone system,
Figure CPT. The cone takes measurements of tip resistance (qc), sleeve resistance (fs), and penetration pore water
pressure (u2). Measurements are taken at either 2.5 or
5 cm intervals during penetration to provide a nearly
continuous profile. CPT data reduction and basic
interpretation is performed in real time facilitating on site decision making. The above mentioned
parameters are stored electronically for further
analysis and reference. All CPT soundings are
performed in accordance with revised ASTM standards
(D 5778 12).

The 5mm thick porous plastic filter element is located
directly behind the cone tip in the u2 location. A new
saturated filter element is used on each sounding to
measure both penetration pore pressures as well as
measurements during a dissipation test (PPDT). Prior
to each test, the filter element is fully saturated with oil under vacuum pressure to improve accuracy.

When the sounding is completed, the test hole is
backfilled according to client specifications. If grouting is used, the procedure generally consists of pushing a
hollow tremie pipe with a “knock out” plug to the
termination depth of the CPT hole. Grout is then
pumped under pressure as the tremie pipe is pulled
from the hole. Disruption or further contamination to
the site is therefore minimized.

Revised 02/05/2015 ii
Gregg 15cm2Standard Cone Specifications
Dimensions
Cone base area 15 cm2
Sleeve surface area 225 cm2
Cone net area ratio 0.80
Specifications
Cone load cell
Full scale range 180 kN (20 tons)
Overload capacity 150%
Full scale tip stress 120 MPa (1,200 tsf)
Repeatability 120 kPa (1.2 tsf)
Sleeve load cell
Full scale range 31 kN (3.5 tons)
Overload capacity 150%
Full scale sleeve stress 1,400 kPa (15 tsf)
Repeatability 1.4 kPa (0.015 tsf)
Pore pressure transducer
Full scale range 7,000 kPa (1,000 psi)
Overload capacity 150%
Repeatability 7 kPa (1 psi)
Note: The repeatability during field use will depend somewhat on ground conditions, abrasion, maintenance and zero load stability.

Revised 2/05/2015 i
Cone Penetration Test Data & Interpretation
The Cone Penetration Test (CPT) data collected are presented in graphical and electronic form in the report. The plots include interpreted Soil Behavior Type (SBT) based on the charts described by Robertson (1990). Typical plots display SBT based on the non normalized charts of Robertson et al (1986). For CPT soundings deeper than 30m, we recommend the use of the normalized charts of Robertson (1990) which can be displayed as SBTn, upon request. The report also includes spreadsheet output of computer calculations of basic interpretation in terms of SBT and SBTn and various geotechnical parameters using current published correlations based on the comprehensive review by Lunne, Robertson and Powell (1997), as well as recent updates by Professor Robertson (Guide to Cone Penetration Testing, 2015). The interpretations are presented only as a guide for geotechnical use and should be carefully reviewed. Gregg Drilling & Testing Inc. does not warranty the correctness or the applicability of any of the geotechnical parameters interpreted by the software and does not assume any liability for use of the results in any design or review. The user should be fully aware of the techniques and limitations of any method used in the software. Some interpretation methods require input of the groundwater level to calculate vertical effective stress.

An estimate of the in situ groundwater level has been made based on field observations and/or CPT results, but should be verified by the user.

A summary of locations and depths is available in Table 1. Note that all penetration depths referenced in the data are with respect to the existing ground surface.

Note that it is not always possible to clearly identify a soil type based solely on qt, fs, and u2. In these situations, experience, judgment, and an assessment of the pore pressure dissipation data should be used to infer the correct soil behavior type.

ZONE SBT
1 2
3 4
5 6
7 8
9 10
11 12
Sensitive, fine grained
Organic materials
Clay
Silty clay to clay
Clayey silt to silty clay
Sandy silt to clayey silt
Silty sand to sandy silt
Sand to silty sand
Sand
Gravely sand to sand
Very stiff fine grained*
Sand to clayey sand*
*over consolidated or cemented
Revised 02/05/2015 i
Cone Penetration Test (CPT) Interpretation
Gregg uses a proprietary CPT interpretation and plotting software. The software takes the CPT data and performs basic interpretation in terms of soil behavior type (SBT) and various geotechnical parameters using current published empirical correlations based on the comprehensive review by Lunne, Robertson and Powell (1997). The interpretation is presented in tabular format using MS Excel. The interpretations are presented only as a guide for geotechnical use and should be carefully reviewed. Gregg does not warranty the correctness or the applicability of any of the geotechnical parameters interpreted by the software and does not assume any liability for any use of the results in any design or review. The user should be fully aware of the techniques and limitations of any method used in the software.

The following provides a summary of the methods used for the interpretation. Many of the empirical correlations to estimate geotechnical parameters have constants that have a range of values depending on soil type, geologic origin and other factors. The software uses ‘default’ values that have been selected to provide, in general, conservatively low estimates of the various geotechnical parameters.

Input:
1 Units for display (Imperial or metric) (atm. pressure, pa = 0.96 tsf or 0.1 MPa) 2 Depth interval to average results (ft or m). Data are collected at either 0.02 or 0.05m and can be averaged every 1, 3 or 5 intervals.
3 Elevation of ground surface (ft or m)
4 Depth to water table, zw (ft or m) – input required
5 Net area ratio for cone, a (default to 0.80)
6 Relative Density constant, CDr (default to 350)
7 Young’s modulus number for sands, (default to 5)
8 Small strain shear modulus number
a. for sands, SG (default to 180 for SBTn 5, 6, 7)
b. for clays, CG (default to 50 for SBTn 1, 2, 3 & 4)
9 Undrained shear strength cone factor for clays, Nkt (default to 15) 10 Over Consolidation ratio number, kocr (default to 0.3) 11 Unit weight of water, (default to w = 62.4 lb/ft3 or 9.81 kN/m3 )
Column
1 Depth, z, (m) – CPT data is collected in meters
2 Depth (ft)
3 Cone resistance, qc (tsf or MPa)
4 Sleeve resistance, fs (tsf or MPa)
5 Penetration pore pressure, u (psi or MPa), measured behind the cone (i.e. u2) 6 Other – any additional data
7 Total cone resistance, qt (tsf or MPa) qt = qc + u (1 a) Revised 02/05/2015 ii
8 Friction Ratio, Rf(%) Rf = (fs/qt) x 100%
9 Soil Behavior Type (non normalized), SBT see note
10 Unit weight, (pcf or kN/m3
) based on SBT, see note
11 Total overburden stress, v (tsf) vo = z
12 In situ pore pressure, uo (tsf) uo = w (z zw)
13 Effective overburden stress, 'vo (tsf ) 'vo = vo uo
14 Normalized cone resistance, Qt1 Qt1= (qt vo) / 'vo
15 Normalized friction ratio, Fr (%) Fr = fs / (qt vo) x 100% 16 Normalized Pore Pressure ratio, Bq Bq = u – uo / (qt vo) 17 Soil Behavior Type (normalized), SBTn see note
18 SBTn Index, Ic see note
19 Normalized Cone resistance, Qtn (n varies with Ic) see note 20 Estimated permeability, kSBT (cm/sec or ft/sec) see note 21 Equivalent SPT N60, blows/ft see note
22 Equivalent SPT (N1)60 blows/ft see note
23 Estimated Relative Density, Dr, (%) see note
24 Estimated Friction Angle, ', (degrees) see note
25 Estimated Young’s modulus, Es (tsf) see note
26 Estimated small strain Shear modulus, Go (tsf) see note 27 Estimated Undrained shear strength, su (tsf) see note 28 Estimated Undrained strength ratio su/ v’ 29 Estimated Over Consolidation ratio, OCR see note Notes:
1 Soil Behavior Type (non normalized), SBT (Lunne et al., 1997 and table below) 2 Unit weight, either constant at 119 pcf or based on Non normalized SBT (Lunne et al., 1997 and table below)
3 Soil Behavior Type (Normalized), SBTn Lunne et al. (1997) 4 SBTn Index, Ic Ic = ((3.47 – log Qt1)2+ (log Fr + 1.22)2)0.5 5 Normalized Cone resistance, Qtn (n varies with Ic)
Qtn = ((qt vo)/pa) (pa/( vo)nand recalculate Ic, then iterate:

When Ic < 1.64, n = 0.5 (clean sand)
When Ic > 3.30, n = 1.0 (clays)
When 1.64 < Ic < 3.30, n = (Ic – 1.64)0.3 + 0.5
Iterate until the change in n, n < 0.01
Revised 02/05/2015 iii
6 Estimated permeability, kSBT based on Normalized SBTn (Lunne et al., 1997 and table below) 7 Equivalent SPT N60, blows/ft Lunne et al. (1997)
60 a N
(qt /p ) = 8.5

4.6 I 1
c 8 Equivalent SPT (N1)60 blows/ft (N1)60 = N60 CN,
where CN = (pa/ vo)0.5
9 Relative Density, Dr, (%) Dr2= Qtn / CDr Only SBTn 5, 6, 7 & 8 Show ‘N/A’ in zones 1, 2, 3, 4 & 9 10 Friction Angle, ', (degrees) tan ' = 0.29
'q
log

2.68 1
vo
c Only SBTn 5, 6, 7 & 8 Show’N/A’ in zones 1, 2, 3, 4 & 9 11 Young’s modulus, Es Es = qt Only SBTn 5, 6, 7 & 8 Show ‘N/A’ in zones 1, 2, 3, 4 & 9 12 Small strain shear modulus, Go
a. Go = SG (qt 'vo pa)1/3 For SBTn 5, 6, 7
b. Go = CG qt For SBTn 1, 2, 3& 4
Show ‘N/A’ in zones 8 & 9
13 Undrained shear strength, su su = (qt vo) / Nkt
Only SBTn 1, 2, 3, 4 & 9 Show ‘N/A’ in zones 5, 6, 7 & 8 14 Over Consolidation ratio, OCR OCR = kocrQt1
Only SBTn 1, 2, 3, 4 & 9 Show ‘N/A’ in zones 5, 6, 7 & 8 The following updated and simplified SBT descriptions have been used in the software:

SBT Zones SBTn Zones
1 sensitive fine grained 1 sensitive fine grained
2 organic soil 2 organic soil
3 clay 3 clay
4 clay & silty clay 4 clay & silty clay
5 clay & silty clay
6 sandy silt & clayey silt
Revised 02/05/2015 iv
7 silty sand & sandy silt 5 silty sand & sandy silt
8 sand & silty sand 6 sand & silty sand
9 sand
10 sand 7 sand
11 very dense/stiff soil* 8 very dense/stiff soil*
12 very dense/stiff soil* 9 very dense/stiff soil*
*heavily overconsolidated and/or cemented
Track when soils fall with zones of same description and print that description (i.e. if soils fall only within SBT zones 4 & 5, print ‘clays & silty clays’) Revised 02/05/2015 v
Estimated Permeability (see Lunne et al., 1997)
SBTn Permeability (ft/sec) (m/sec)
1 3x 10 8
1x 10 8
2 3x 10 71x 10 7
3 1x 10 93x 10 10
4 3x 10 81x 10 8
5 3x 10 6
1x 10 6
6 3x 10 41x 10 4
7 3x 10 21x 10 2
8 3x 10 6
1x 10 6
9 1x 10 83x 10 9
Estimated Unit Weight (see Lunne et al., 1997)
SBT Approximate Unit Weight (lb/ft3
) (kN/m3)
1 111.4 17.5
2 79.6 12.5
3 111.4 17.5
4 114.6 18.0
5 114.6 18.0
6 114.6 18.0
7 117.8 18.5
8 120.9 19.0
9 124.1 19.5
10 127.3 20.0
11 130.5 20.5
12 120.9 19.0
Revised 02.05.2015 i
Pore Pressure Dissipation Tests (PPDT)
Pore Pressure Dissipation Tests (PPDT’s) conducted at various intervals can be used to measure equilibrium water pressure (at the time of the CPT). If conditions are hydrostatic, the equilibrium water pressure can be used to determine the approximate depth of the ground water table. A PPDT is conducted when penetration is halted at specific intervals determined by the field representative. The variation of the penetration pore pressure (u) with time is measured behind the tip of the cone and recorded.

Pore pressure dissipation data can be
interpreted to provide estimates of:

Equilibrium piezometric pressure
Phreatic Surface
In situ horizontal coefficient of
consolidation (ch)
In situ horizontal coefficient of
permeability (kh)
In order to correctly interpret the
equilibrium piezometric pressure and/or the
phreatic surface, the pore pressure must be
monitored until it reaches equilibrium,
Figure PPDT. This time is commonly referred
to as t100, the point at which 100% of the
excess pore pressure has dissipated.

A complete reference on pore pressure
dissipation tests is presented by Robertson
et al. 1992 and Lunne et al. 1997.

A summary of the pore pressure dissipation
tests are summarized in Table 1.

Revised 02/05/2015 i
Seismic Cone Penetration Testing (SCPT)
Seismic Cone Penetration Testing (SCPT) can be conducted at various intervals during the Cone Penetration Test. Shear wave velocity (Vs) can then be calculated over a specified interval with depth. A small interval for seismic testing, such as 1 1.5m (3 5ft) allows for a detailed look at the shear wave profile with depth. Conversely, a larger interval such as 3 6m (10 20ft) allows for a more average shear wave velocity to be calculated. Gregg’s cones have a horizontally active geophone located 0.2m (0.66ft) behind the tip.

To conduct the seismic shear wave test, the penetration of the cone is stopped and the rods are decoupled from the rig. An automatic hammer is triggered to send a shear wave into the soil. The distance from the source to the cone is calculated knowing the total depth of the cone and the horizontal offset distance between the source and the cone. To calculate an interval velocity, a minimum of two tests must be performed at two different
depths. The arrival times
between the two wave traces
are compared to obtain the
difference in time ( t). The
difference in depth is
calculated ( d) and velocity
can be determined using the
simple equation: v = d/ t
Multiple wave traces can be
recorded at the same depth
to improve quality of the
data.

A complete reference on
seismic cone penetration
tests is presented by
Robertson et al. 1986 and
Lunne et al. 1997.

A summary the shear wave
velocities, arrival times and
wave traces are provided
with the report.
(S)
1 2
t 1
2 1 2
2 1
2 1
Revised 3/09/2015 i
Groundwater Sampling
Gregg Drilling & Testing, Inc. conducts groundwater
sampling using a sampler as shown in Figure GWS. The groundwater sampler has a retrievable stainless steel or disposable PVC screen with steel drop off
tip. This allows for samples to be taken at multiple
depth intervals within the same sounding location.

In areas of slower water recharge, provisions may
be made to set temporary PVC well screens during
sampling to allow the pushing equipment to
advance to the next sample location while the
groundwater is allowed to infiltrate.

The groundwater sampler operates by advancing

44.5mm (1¾ inch) hollow push rods with the filter
tip in a closed configuration to the base of the
desired sampling interval. Once at the desired
sample depth, the push rods are retracted; exposing
the encased filter screen and allowing groundwater
to infiltrate hydrostatically from the formation into
the inlet screen. A small diameter bailer
(approximately ½ or ¾ inch) is lowered through the
push rods into the screen section for sample
collection. The number of downhole trips with the
bailer and time necessary to complete the sample
collection at each depth interval is a function of
sampling protocols, volume requirements, and the
yield characteristics and storage capacity of the
formation. Upon completion of sample collection,
the push rods and sampler, with the exception of
the PVC screen and steel drop off tip are retrieved
to the ground surface, decontaminated and
prepared for the next sampling event.

For a detailed reference on direct push groundwater
sampling, refer to Zemo et. al., 1992.

Revised 02/05/2015 i
Soil Sampling
Gregg Drilling & Testing, Inc. uses a piston type
push in sampler to obtain small soil samples
without generating any soil cuttings, Figure SS. Two different types of samplers (12 and 18 inch) are used depending on the soil type and density.

The soil sampler is initially pushed in a "closed"
position to the desired sampling interval using
the CPT pushing equipment. Keeping the sampler
closed minimizes the potential of cross
contamination. The inner tip of the sampler is
then retracted leaving a hollow soil sampler with
inner 1¼” diameter sample tubes. The hollow
sampler is then pushed in a locked "open"
position to collect a soil sample. The filled
sampler and push rods are then retrieved to the
ground surface. Because the soil enters the
sampler at a constant rate, the opportunity for
100% recovery is increased. For environmental
analysis, the soil sample tube ends are sealed
with Teflon and plastic caps. Often, a longer "split
tube" can be used for geotechnical sampling.

For a detailed reference on direct push soil
sampling, refer to Robertson et al, 1998.

ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX B-3
Previous Subsurface Data (Law Crandall, 1999)

SW
SP
SM
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, very fine to fine grained, gray, slightly moist, medium dense, trace silt, micaceous.
@5.0 ft. some iron oxide, some silt.
@10.0 ft. fine to medium grained.
@15.0 ft. wet, with roots, trace clay.
@18.7 ft. groundwater encountered.
@20.0 ft. SILTY SAND, very fine to fine grained, dark gray, wet, medium dense, with roots, micaceous.
@25.0 ft. dense.

TOTAL DEPTH 26.0 FEET
GROUNDWATER AT 18.7 FEET

NO CAVING OBSERVED
R
R
R
R
R
R
14 21
16 14
14 41
11 4
22 78
91 CON
94 96
90 98
87 3.3

1.1 6.8

20.3 30.6

11.4 140 lbs
Cottonwood & Park Center
1 OF 1
30 in
B-1
19 341
5 10
15 20
25 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
340
335
330
325
320
315

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-1
SM
SP
SM
SP
SM
SP
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, very fine to fine grained, brownish gray, dry, medium dense, micaceous.
@5.0 ft. fine to medium grained.
@10.0 ft. moist.
@14.7 ft. groundwater encountered.
@15.0 ft. SILTY SAND, fine grained, dark gray, wet, medium dense, trace clay, micaceous.
@20.0 ft. fine to medium grained, some clay.
@25.0 ft. fine grained.
@30.0 ft. SAND, fine to medium grained, dark gray, wet, medium dense.
@31.0 ft. SILTY SAND, fine grained, dark gray, wet, medium dense. @35.0 ft. SAND, fine to medium grained, dark gray, wet, very dense, some gravel.

R
R
R
R
R
R
S
S
13 14
16 17
18 16
3,4,9
36,50 for
3"
7 76
86 87
MAX,
EI,
HY,
CHEM
96 101
104
92 1.9

1.2 18.5

19.3 26.3

18.6 11.6

21.1 140 lbs
Cottonwood & Park Center
1 OF 2
30 in
B-2
15 341
5 10
15 20
25 30
35 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
340
335
330
325
320
315
310
305

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-2
SC
SP
@40.0 ft. CLAYEY SAND, fine grained, yellowish gray, slightly moist, hard.
@45.0 ft. SAND, fine to coarse grained, dark gray to gray, slightly moist, very dense, some gravel.

TOTAL DEPTH 47.0 FEET; REFUSAL AT 47.0 FEET
GROUNDWATER AT 14.7 FEET

NO CAVING OBSERVED
S
S
15,17,23
13,30,50
for 5"

10.1 140 lbs
Cottonwood & Park Center
2 OF 2
30 in
B-2
15 341
45 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
300
295

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-2
SM
SP
SM
SP
SM
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, fine to medium grained, brownish gray, slightly moist, medium dense, trace silt.
@5.0 ft. SILTY SAND, fine grained, dark gray, slightly moist, medium dense.
@10.0 ft. SAND, fine grained, gray, slightly moist, medium dense. @15.0 ft. medium to coarse grained, brownish gray, moist. @16.8 ft. groundwater encountered.
@20.0 ft. wet, dense, trace silt.
@25.0 ft. SILTY SAND, fine to coarse grained, brownish dark gray, wet, medium dense.

TOTAL DEPTH 26.0 FEET
GROUNDWATER AT 16.8 FEET

NO CAVING OBSERVED
R
R
R
R
R
R
12 15
14 16
37 28
17 15
22 33
65 CON,
HY
93 96
91 93
103

5.0 4.2

6.9 9.5

14.7 15.1
140 lbs
Cottonwood & Park Center
1 OF 1
30 in
B-3
17 344
5 10
15 20
25 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
340
335
330
325
320

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-3
SM
SP
CL
SP
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 SAND, fine grained, brownish gray, slightly moist, medium dense.
@5.0 ft. trace silt, micaceous.
@10.0 ft. fine to coarse grained, gray, slightly moist, medium dense. @15.0 ft. brownish gray, wet.
@16.2 ft. groundwater encountered.
@25.0 ft. SILTY CLAY, brown, wet, firm.
@35.0 ft. SAND, coarse grained, brownish gray, slightly moist, very dense.

TOTAL DEPTH 36.0 FEET; REFUSAL AT 36.0 FEET
GROUNDWATER AT 16.2 FEET

NO CAVING OBSERVED
R
R
R
R
R
R
S
S
S
13 18
27 18
27 15
3,7,12
50 for 1"
50 for 4"
22 9
11 60
83 MAX,
EI,
HY,
CHEM
104
89 94
94 91

4.9 3.0

3.1 17.2

11.1 26.0

23.3 22.6

13.4 140 lbs
Cottonwood & Park Center
1 OF 1
30 in
B-4
16 344
5 10
15 20
25 30
35 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
340
335
330
325
320
315
310

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-4
SM
SP
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, very fine to fine grained, gray, slightly moist, medium dense, trace silt, micaceous.
@5.0 ft. some iron oxide, trace silt.

TOTAL DEPTH 10.0 FEET

NO GROUNDWATER ENCOUNTERED

NO CAVING OBSERVED
Cottonwood & Park Center
1 OF 1
339 P-1
5 10

TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
335
330

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-5
SM
SP
YOUNG ALLUVIAL DEPOSITS (Qya): SILTY SAND, fine grained, brown, dry, loose.
@2.5 ft. SAND, very fine to fine grained, brownish gray, slightly moist, medium dense, trace silt, micaceous.

TOTAL DEPTH 5.0 FEET

NO GROUNDWATER ENCOUNTERED

NO CAVING OBSERVED
Cottonwood & Park Center
1 OF 1
339 P-2
5 TYPE OF DRILL RIG
DRILLER SAT- MOISTURE CONT (%)
1/6/25
(%) URATION
DATE STARTED 1/6/25
335

GEOTECHNICAL DESCRIPTION OTHER TESTS

S SPT (SPLIT SPOON) SAMPLE

R RING (DRIVE) SAMPLE
SAMPLE TYPES:

SHEET
NOTE

LOGGED BY GROUP
J: JOINTING
B: BEDDING
S: SHEAR
C: CONTACT
F: FAULT
RS: RUPTURE SURFACE
1-0572

GROUNDWATER

SEEPAGE
(Feet)
PROJECT NO.

GEOTECHNICAL BORING LOG
GROUND ELEV.
8" Hollow Stem Auger
2R Drilling Inc SYMBOL LITHOLOGY BLOWS
B BULK SAMPLE T TUBE SAMPLE TYPE SAMPLE ELEV DRY (pcf) DENSITY BORING DESIG.

DROP
DRIVE WT.

GW DEPTH (FT)

PROJECT NAME

DATE FINISHED YH DEPTH
Alta California Geotechnical, Inc.

P.N. 1-0572 PLATE B-6
ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX C
Laboratory Testing
Project No. 1-0572 Page C-1
January 29, 2025

LABORATORY TESTING
The following laboratory tests were performed on representative samples in accordance with the applicable latest standards or methods from the ASTM, California Building Code (CBC) and California Department of Transportation.

Classification
Soils were classified with respect to the Unified Soil Classification System (USCS) in accordance with ASTM D-2487 and D-2488.

Particle Size Analysis
Modified hydrometer testing was conducted to aid in classification of the soil. The results of the particle size analysis are presented in Table 7-1 and Table C.

Maximum Density/Optimum Moisture
The maximum dry density and optimum moisture content of one (1) representative bulk sample was evaluated in accordance with ASTM D-1557. The results are summarized in Table C.

Expansion Index Tests
One (1) expansion index test was performed to evaluate the expansion potential of typical onsite soil. Testing was carried out in general conformance with ASTM Test Method D-4829. The results are presented in Table C.

Consolidation Tests
Consolidation testing was performed on two (2) relatively “undisturbed” soil sample at their natural moisture content in accordance with procedures outlined in ASTM D-2435. The samples were placed in a consolidometer and loads were applied incrementally in geometric progression. The samples (2.42-inches in diameter and 1-inch in height) were permitted to consolidate under each load increment until the slope of the characteristic linear secondary compression portion of the thickness versus log of time plot was apparent. The percent consolidation for each load cycle was recorded as the ratio of the amount of vertical Project No. 1-0572 Page C-2
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.
compression to the original 1-inch height. The consolidation test results are shown on Plates C1 and C-2 Chemical Analyses
Chemical testing was performed on one select sample. The results of this test (sulfate content, resistivity, chloride content and pH) is presented on Table C.

B-1 5 Sand (Qya) SP SEE PLATE
C-1
B-2 5 Sand (Qya) SP 119.5 11.8 6 88 1 5 1 MinResist:12,870-Ohmcm pH:8.4,Chl:480ppm,SO4:0.004%
B-3 5 Silty Sand (Qya) SM 0 67 27 6 SEE PLATE
C-2
B-4 2.5 Sand (Qya) SP 109.4 12.0 1 97 0 2 0 MinResist:19,440-Ohmcm pH:8.2,Chl:300ppm,SO4:0.003%

OTHER TESTS

REMARKS

BORING DEPTH
(FEET)

SOIL DESCRIPTION GROUP
SYMBOL
DIRECT
SHEAR

EXPANSION
INDEX
UBC 18-2

MAXIMUM

DENSITY
(PCF)

TABLE C

SUMMARY OF LABORATORY TEST DATA
P.N. 1-0572

OPTIMUM

MOISTURE

CONTENT
(%)
CONSOL
SILT
(0.075mm-0.005mm)
(%)
SAND
(4.76mm-0.075mm)
(%)
PLUS NO.4 SEIVE
(plus 4.76mm)
(%)
CLAY
(minus 0.005mm)
(%)
Alta California Geotechnical, Inc.
-2.0
-1.0
0 1.0

2.0 3.0

4.0 5.0

6.0 7.0

8.0 0.1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 910
REMARKS: WATER ADDED AT 1.07 TSF

CONSOLIDATION CURVE PERCENT CHANGE IN HEIGHT
PLATE C-1

COMPRESSIVE STRESS IN TSF
group typical names density (pcf) symbolsieve (%)

1.1 moist. (%)
in situdry depth (ft.)

5.0B-1
satur. (%)
96 -200
SP Sand (Qya)
boring in situ
4 Alta California Geotechnical, Inc.

P.N. 1-0572
-2.0
-1.0
0 1.0

2.0 3.0

4.0 5.0

6.0 7.0

8.0 0.1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 910
REMARKS: WATER ADDED AT 1.07 TSF

CONSOLIDATION CURVE PERCENT CHANGE IN HEIGHT
PLATE C-2

COMPRESSIVE STRESS IN TSF
group typical names density (pcf) symbolsieve (%)

4.2 moist. (%)
in situdry depth (ft.)

5.0B-3
satur. (%)
96 -200
SM Silty Sand (Qya)
boring in situ
15 33
Alta California Geotechnical, Inc.

P.N. 1-0572

APPENDIX D
Liquefaction Analysis
Project No. 1-0572 Page D-1
January 29, 2025

APPENDIX D

LIQUEFACTION ANALYSIS
A liquefaction analysis was performed for the site based on CPT data obtained during the previous investigations. Our analysis was based on City of Los Angeles guidelines (City of Los Angeles, 2020) and utilized the PGAM, the predominant earthquake magnitude assuming a 2% probability of exceedance in 50 years, and a factor of safety of 1.0. The results of this liquefaction analysis are presented on Plates D-1 through D-11.

APPENDIX E
Maintenance and Improvement Considerations
Project No. 1-0572 Page E-1
January 29, 2025

MAINTENANCE AND IMPROVEMENT CONSIDERATIONS
General
Owners purchasing property must assume a certain degree of responsibility for improvements and for maintaining conditions around their home. Of primary importance from a geotechnical standpoint are maintaining drainage patterns and minimizing the soil moisture variation below all improvements. Such design, construction and owner maintenance provisions may include:
 Employing contractors for improvements who design and build in recognition of local building codes and specific site soils conditions.
 Establishing and maintaining positive drainage away from all foundations, walkways, driveways, patios, and other improvements.
 Avoiding the construction of planters adjacent to structural improvements.

Alternatively, planter sides/bottoms can be sealed with an impermeable membrane and drained away from the improvements via subdrains into approved disposal areas.  Sealing and maintaining construction/control joints within concrete slabs and walkways to reduce the potential for moisture infiltration into the subgrade soils.  Utilizing landscaping schemes with vegetation that requires minimal watering. Watering should be done in a uniform manner, as equally as possible on all sides of the foundation, keeping the soil "moist" but not allowing the soil to become saturated.  Maintaining positive drainage away from structures and providing roof gutters on all structures with downspouts that are designed to carry roof runoff directly into area drains or discharged well away from the foundation areas.  Avoiding the placement of trees closer to the proposed structures than a distance of one-half the mature height of the tree.
 Observation of the soil conditions around the perimeter of the structure during extremely hot/dry or unusually wet weather conditions so that modifications can be made in irrigation programs to maintain relatively uniform moisture conditions.

Sulfates
Owners should be cautioned against the import and use of certain inorganic fertilizers, soil amendments, and/or other soils from offsite sources in the absence of specific information relating to their chemical composition. Some fertilizers have been known to leach sulfate compounds into soils and increase the sulfate concentrations to potentially detrimental levels.

Project No. 1-0572 Page E-2
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

Site Drainage
 The owners should be made aware of the potential problems that may develop when drainage is altered through construction of hardscape improvements. Ponded water, drainage over the slope face, leaking irrigation systems, overwatering, or other conditions which could lead to ground saturation must be avoided.  No water should be allowed to flow over the slopes. No alteration of pad gradients should be allowed that would prevent pad and roof runoff from being directed to approved disposal areas.
 Drainage patterns have been established at the time of the fine grading should be maintained throughout the life of the structure. No alterations to these drainage patterns should be made unless designed by qualified professionals in compliance with local code requirements and site-specific soils conditions.

Slope Drainage
 Residents should be made aware of the importance of maintaining and cleaning all interceptor ditches, drainage terraces, down drains, and any other drainage devices, which have been installed to promote slope stability.
 Subsurface drainage pipe outlets may protrude through slope surfaces and/or wall faces. These pipes, in conjunction with the graded features, are essential to slope and wall stability and must be protected in-place. They should not be altered or damaged in any way.

Planting and Irrigation of Slopes
 Seeding and planting of the slopes should be planned to achieve, as rapidly as possible, a well-established and deep-rooted vegetal cover requiring minimal watering.  It is the responsibility of the landscape architect to provide such plants initially and of the residents to maintain such planting. Alteration of such a planting scheme is at the resident's risk.
 The resident is responsible for proper irrigation and for maintenance and repair of properly installed irrigation systems. Leaks should be fixed immediately.  Sprinklers should be adjusted to provide maximum uniform coverage with a minimum of water usage and overlap. Overwatering with consequent wasteful runoff and serious ground saturation must be avoided.
 If automatic sprinkler systems are installed, their use must be adjusted to account for seasonal and natural rainfall conditions.

Project No. 1-0572 Page E-3
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

Burrowing Animals
 Residents must undertake a program to eliminate burrowing animals. This must be an ongoing program in order to promote slope stability.

Owner Improvement
Owner improvements (pools, spas, patio slabs, retaining walls, planters, etc.) should be designed to account for the terrain of the project, as well as expansive soil conditions and chemical characteristics. Design considerations on any given lot may need to include provisions for differential bearing materials, ascending/descending slope conditions, bedrock structure, perched (irrigation) water, special geologic surcharge loading conditions, expansive soil stresses, and long-term creep/settlement.

All owner improvements should be designed and constructed by qualified professionals utilizing appropriate design methodologies, which account for the on-site soils and geologic conditions.

Each lot and proposed improvement should be evaluated on an individual basis.

Setback Zones
Manufactured slopes maybe subject to long-term settlement and creep that can manifest itself in the form of both horizontal and vertical movement. These movements typically are produced as a result of weathering, erosion, gravity forces, and other natural phenomenon. A setback adjacent to slopes is required by most building codes, including the California Building Code. This zone is intended to locate and support the residential structures away from these slopes and onto soils that are not subject to the potential adverse effects of these natural phenomena.

Project No. 1-0572 Page E-4
January 29, 2025
ALTA CALIFORNIA GEOTECHNICAL, INC.

The owner may wish to construct patios, walls, walkways, planters, swimming pools, spas, etc. within this zone. Such facilities may be sensitive to settlement and creep and should not be constructed within the setback zone unless properly engineered. It is suggested that plans for such improvements be designed by a professional engineer who is familiar with grading ordinances and design and construction requirements. In addition, we recommend that the designer and contractor familiarize themselves with the site specific geologic and geotechnical conditions on the specific lot.

ALTA CALIFORNIA GEOTECHNICAL, INC.

APPENDIX F
Earthwork Specifications

P-1 B-1 P-2 B-2 Qya Qya B-4B-3 P-3 P-2 P-1 CPT-13 CPT-9 CPT-11 CPT-12 CPT-10 CPT-4 CPT-8 CPT-3 CPT-5 CPT-2 CPT-7 CPT-1 CPT-6 5-1 170 N. MAPLE STREET, STE 108, CORONA, CA 92880 TELEPHONE: (951) 509-7090
ALTA CALIFORNIA GEOTECHNICAL, INC. LEGEND YOUNG ALLUVIAL DEPOSITS APPROXIMATE LOCATION OF HOLLOW STEM AUGER BORING (THIS REPORT) APPROXIMATE LOCATION OF INFILTRATION TEST (THIS REPORT) APPROXIMATE LOCATION OF CPT BORING (LEIGHTON, 2017) APPROXIMATE LOCATION OF CPT BORING (LEIGHTON, 2024) APPROXIMATE LOCATION OF INFILTRATION TEST (LEIGHTON, 2024) APPROXIMATE LOCATION OF BORING (LAW CRANDELL, 1999) LIMITS OF REPORT Qya PLATE 1 B-4 P-2 P-3 5-1 CPT-6 CPT-13 Appendix E-1
Request for a Conditional Letter of Map Revision for
Santee 3 Multi-family Housing,
San Diego River, San Diego, CA
Request For A Conditional
Letter of Map Revision
For
Santee 3 Multi-Family Housing
San Diego River
County of San Diego, CA
RICK Job No.19969
January 13, 2025

REQUEST FOR A CONDITIONAL LETTER OF MAP REVISION (CLOMR) FOR
SANTEE 3 MULTI-FAMILY HOUSING
Job Number 19969
_____________________________________
Shavger Rekani
R.C.E #90893, Exp. 03/26
Prepared For:

Santee 3 Inv, LLC.
3121 Michelson Drive
Irvine, CA 92612
Prepared By:

RICK
5620 Friars Road
San Diego, CA 92110
(619) 291-0707
www.rickengineering.com
January 13, 2025
Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25

TABLE OF CONTENTS

1.0 INTRODUCTION .................................................................................................................... 1

1.1 ESA Compliance................................................................................................................... 1 Figure 1: Vicinity Map................................................................................................................ 2

2.0 HYDROLOGIC INFORMATION ........................................................................................... 3

3.0 HYDRAULIC ANALYSIS ...................................................................................................... 4

4.0 MODELS .................................................................................................................................. 6

4.1 FEMA Effective Data ........................................................................................................... 6

4.2 Duplicate Effective .............................................................................................................. 6

4.3 Corrected Effective/Existing Conditions ............................................................................. 7

4.4 Proposed Condition............................................................................................................... 8

5.0 HYDRAULIC RESULTS......................................................................................................... 9

5.1 Proposed Condition vs Existing Condition ......................................................................... 9

5.2 Corrected Effective vs Duplicate Effective ……………………………………………….9

5.3 Floodplain and Floodway Delineation……………………………………………………10

6.0 DIGITAL DATA .................................................................................................................... 12 Tables
Table 1: Summary of Starting Water Surface Elevations……………………………………..…3 Table 2: Summary of Effective FEMA Flow Rates …………………………………………..…4 Table 3: 100-Year Storm Event Base Flood Elevations Comparison Table …………………...11 Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
List of Appendices
Appendix 1: FEMA MT-2 Forms
Appendix 2: FEMA Payment Form
Appendix 3: ESA Compliance Support Documentation
Appendix 4: Public Notification Documents
Appendix 5: Effective Flood Insurance Study Excerpts
Appendix 6: Effective Data
Appendix 7: Duplicate Effective Analysis
Appendix 8: Corrected Effective Condition Workmap
Appendix 9: Corrected Effective Condition Analysis
Appendix 10: Proposed Condition Workmap
Appendix 11: Proposed Condition Analysis
Appendix 12: Revised FIRMette
Appendix 13: As-Built Plans
Appendix 14: Proposed Condition Plans
Appendix 15: Digital Data
Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
1 1.0 INTRODUCTION
This report supports a Conditional Letter of Map Revision (CLOMR) for the Santee 3 MultiFamily Housing project (project). The project proposes construction activities within the Federal Emergency Management Agency (FEMA) defined floodplain for San Diego River and revisions to the floodplain mapping between FEMA cross sections BI and BK as shown on FEMA FIRM Panel 06073C1651G, effective November 20, 2015. FEMA has designated this portion of the San Diego River as Zone AE, and Zone X. The limits of this project are within the City of Santee, San Diego County, CA, community 060703.

An annotated copy of the effective Flood Insurance Rate Map (FIRM) for the revised portion of San Diego River is included in Appendix 12. All applicable FEMA MT-2 forms required for this CLOMR request are located in Appendix 1. The project location is shown on the Figure 1: Vicinity Map, following.

1.1 ESA Compliance
Procedure Memorandum 64, issued by FEMA in August 2010, requires that Endangered Species Act (ESA) compliance must be documented to FEMA prior to issuance of CLOMR. The ESA compliance documents will be included in Appendix 3 prior to the next submittal.

Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
2 Figure 1: Vicinity Map
Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
3 2.0 HYDROLOGIC INFORMATION
The Hydrologic Data used to model San Diego River was taken from Table 9 of the San Diego County Flood Insurance Study (FIS) dated March 22, 2022 as well as the Effective FEMA model for this location dated November 20, 2015. The flow rates in the FIS match the flow rates used in the effective models. Table 1, below, summarizes the flow rates used for the models contained within this CLOMR. A copy of applicable excerpts from the FIS are included in Appendix 5 of this report.

Table 1: Summary of Effective FEMA Flow Rates
Flooding Source and
Location Source
Drainage
Area
(SqMi)
Peak Discharge (cfs)
10-Year 50-Year 100-Year 500-
Year
San Diego River –
Cuyamaca Street to
Cottonwood Avenue
FIS –
Effective
Model.

LOMR
November
20, 2015
34,000
San Diego River –
Confluence with Murphy
Canyon Creek
FIS 420.0 3,100 17,000 36,000 112,000
Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
4 3.0 HYDRAULIC ANALYSIS
The U.S. Army Corps of Engineers HEC-RAS Water Surface Profiles program Version 6.5 was utilized to model the hydraulics for San Diego River. HEC-RAS is intended for calculating water surface elevations (WSELs) for supercritical, subcritical and mixed flow regimes in natural or man-made channels. The effects of the various obstructions such as bridges and culverts may be considered in the computations.

3.0.1 Starting Water Surface Elevations
The boundary conditions for all models submitted as a part of this CLOMR were modeled as a known starting water surface elevation (WSEL) for each flood profile. The starting WSEL for each flood profile was obtained from the effective FEMA model at the effective model cross section 112, FEMA cross section BI. The following table summarizes the starting water surface elevation modeled in the analyses.

Table 2: Summary of Starting Water Surface Elevations
Profile Starting WSEL
(ft, NGVD)
100-Year Floodplain (FP) 337.8
Floodway (FW) 338.2
The hydraulic modeling was prepared as a subcritical flow analysis as the Froude numbers within the models are generally much less than 1. Therefore, no upstream boundary conditions were specified for the analysis.

3.0.2 Topography and Datums
Two sources of topographic information were used to update the cross sections for the corrected effective and proposed condition models. The topographic information used in the vicinity of the site were based project specific aerial survey flown on November 27, 2023, resulting in 1-foot contours. Topographic data from the wider study area was obtained from the SANGIS San Diego County wide 2-ft contours from 2018.

Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
5 The City of Santee, the site topography, and the effective models utilize the NGVD-29 vertical datum. Therefore, the hydraulic analyses prepared for this study also retained the NGVD-29 vertical datum. Per comparisons from the FEMA FIS data on the NAVD-88 datum and the effective HEC-2 model data, NAVD-88 elevations are 2.1 feet above NGVD-29 elevations for the studied reach.

3.0.3 Bridge
The bridge crossing for Cuyamaca Street was included in the effective HEC-RAS analysis, however, the Corrected Effective/Existing model was terminated at Section BI (112) and therefore was upstream of this crossing. No bridge modeling was included in this hydraulic analysis.

3.0.4 Manning’s n Values
Manning’s n-values for the corrected effective and proposed conditions models were assigned to the model based on effective model n values and aerial imagery for locations on the project site.

3.0.5 Blocked Obstructions/Ineffective Flow
Ineffective flow areas and blocked obstructions were added to the cross sections as appropriate.

Areas of ineffective flow were modeled in the conveyance shadow of the bridge or obstructions, as well as areas of flow expansion or contraction included in the modeling. A contraction ratio of 1:1 and an expansion ratio of 2:1 were utilized in the models. Locations of blocked obstructions and ineffective flow are based on aerial imagery and topographic information within the limits of the study and are shown on the HEC-RAS workmaps in Appendices 8 and 10.

3.0.6 Sediment Transport Effects
The effects of sediment transport are not included in the effective mapping and therefore have not been incorporated into the hydraulic modeling of reach of interest for the San Diego River.

Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
6 4.0 MODELS
The following provides a description of the hydraulic analyses of San Diego River included in this report.

4.1 FEMA Effective Data
RICK submitted an FIS data request to FEMA and received the effective model data from FEMA on January 3, 2024. The effective model data provided consisted of electronic PDF data and an executable HEC-RAS for the November 20, 2015 LOMR (Effective Model). The effective model output for the 100-year floodplain and floodway WSELs were compared with the WSELs in the FIS and were found to generally match, confirming the validity of the effective data. Please refer to Table 3 for a summary of the effective WSELs from the FIS and the effective model output.

4.2 Duplicate Effective
The provided HEC-RAS electronic project files for the effective model were used for the duplicate effective electronic file and was then executed using HEC-RAS v.6.5 for the portion of San Diego River relevant to this study.

HEC-RAS FILES:

The following HEC-RAS files reflect the duplicate effective HEC-RAS hydraulic model for the San Diego River:

File: Title:

Project: Santee3MultiFamCLOMR.prj N/A
Plan: Santee3MultiFamCLOMR.p01 DuplicateEffective
Geometry: Santee3MultiFamCLOMR.g01 DuplicateEffective
Flow: Santee3MultiFamCLOMR.f02 FEMA_FIS_Flows_DupEff
Copies of the duplicate effective model output is included in Appendix 7. Executable copies of the models are included with the digital data in Appendix 15.

Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
7 4.3 Corrected Effective/Existing Conditions
The following changes were made to the duplicate effective model to create the corrected effective/existing conditions model:
• The model was shortened to include only the revised reach (Sections 112 - 485). • Cross sections 116 - 485 were revised to utilize current topography. • The encroachment stations for the model were revised to match the current NFHL encroachment stations were possible. These encroachments were revised as required to maintain no negative surcharges, no surcharges in excess of 1.0 foot, follow the revised inundation limits, avoid ineffective flow areas, and remain outside of bank stations. • It was determined that no additional cross sections are required to analyze the proposed grading impacts of the project in the corrected effective/existing conditions model. The site is blocked from effective flow by high ground and ineffective flow areas. The area of flooding adjacent to the project site are areas where water can flow into and pond, but it is not conveying effective flow from the river. This is because the flow is not able to expand and contract into and out of the area to provide conveyance for the river. The cross section locations included in the model are consistent with the effective model and follow standard modeling practices.

HEC-RAS FILES:

The following HEC-RAS files reflect the corrected effective hydraulic model for the San Diego River:

File: Title:

Project: Santee3MultiFamCLOMR.prj N/A
Plan: Santee3MultiFamCLOMR.p02 CorrectedEffective
Geometry: Santee3MultiFamCLOMR.g02 CorrectedEffective
Flow: Santee3MultiFamCLOMR.f01 FEMA_FIS_Flows
Please refer to Table 3 for a summary of the corrected effective condition calculated WSELs. A corrected effective condition HEC-RAS workmap is included in Appendix 8. A hard copy printout of the HEC-RAS model is included in Appendix 9. Executable copies of the HEC-RAS model are included with the digital data in Appendix 15.

Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
8 4.4 Proposed Condition
The proposed condition modeling reflects the proposed project grading.

HEC-RAS FILES:

The following HEC-RAS files reflect the proposed condition model for the San Diego River:

File: Title:

Project: Santee3MultiFamCLOMR.prj N/A
Plan: Santee3MultiFamCLOMR.p04 Proposed
Geometry: Santee3MultiFamCLOMR.g04 Proposed
Flow: Santee3MultiFamCLOMR.f01 FEMA_FIS_Flows
Please refer to Table 3 for a summary of the proposed condition calculated WSELs. A proposed condition HEC-RAS workmap is included in Appendix 10. A hard copy printout of the HEC-RAS model is included in Appendix 11. The proposed project plans are included in Appendix 14.

Executable copies of the HEC-RAS model are included with the digital data in Appendix 15.

Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
9 5.0 HYDRAULIC RESULTS

5.1 Proposed Condition vs. Corrected Effective
Hydraulic models were created in the HEC-RAS program to evaluate the hydraulic impacts to the San Diego River resulting from the proposed project. The hydraulic models cross sections and WSEL results and outputs are in relation to NGVD-29 vertical datum, based on the site-specific topography and effective model that was also in NGVD-29. All of the WSELs in the following table have been converted to NAVD-88 to be consistent with data shown in the San Diego County FIS, NAVD-88 elevations are 2.1 feet above NGVD-29 elevations. The corrected effective and proposed condition HEC-RAS workmaps are included in Appendices 8 and 10 respectively. Hard copies of the corrected effective and proposed condition HEC-RAS output can be found in Appendices 9 and 11 respectively. A copy of the digital models can be found with the electronic files in Appendix 15.

The proposed project and the associated fill area within the San Diego River floodplain result in no increases in water surface elevation between the corrected effective condition and proposed condition models for the base flood (100-year) event. The maximum BFE for the proposed structures on site is at cross section 485 – 346.46’ (NAVD-88), and the BFE at the westernmost extent of the development is at section 120 - 343.0’. The project pad grading varies from 351.0’ (NAVD-88) at the east to 347.3’ (NAVD-88) at the west, elevating structures above the BFE. It is anticipated that the proposed structures will be reasonably safe from flooding due to San Diego River from the 100-year storm event.

5.2 Corrected Effective vs. Duplicate Effective
As shown in Table 3, the corrected effective condition model revisions resulted in little change to the duplicated effective WSELs except at section 483, where a 3.3’ increase was shown. This increase is likely due to the utilization of updated topographical information that better defines the subject area.

Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
10 5.3 Floodplain and Floodway Delineation
Floodplain delineation is based on computed WSELs from the HEC-RAS analysis prepared for each condition. The floodway delineation is based on the effective workmaps and NFHL delineations. Revisions to the Floodway were only made as required to maintain no negative surcharges, no surcharges in excess of 1.0 foot, follow the revised inundation limits, avoid ineffective flow areas, and remain outside of bank stations. The revised effective FIRMettes in Appendix 12 illustrate how the 100-year floodplain will be modified as a result of the updated CLOMR modeling.

Table 3: San Diego River - 100-Year Storm Event Base Flood Elevations Comparison Table Job Name: Santee 3 Multi Family
Job Number: 19969
FP=Floodplain FW=Floodway Date: #####
[1]
D/S reach
length (ft)
485 343.2 343.7 0.5 485 346.28 346.5 0.2 485 346.28 346.5 0.2 485.00 346.49 346.64 0.15 13 - 361.87 346.46 346.63 0.17 0.0 0.2 -0.03483 483 342.36 343.0 0.6 483 342.35 343.0 0.6 483.00 345.68 346.68 1.00 595.44 345.86 346.71 0.85 0.0 3.3 0.18480 343.0 343.5 0.5 480 342.17 342.7 0.6 480 342.16 342.7 0.6 480.00 341.89 342.45 0.56 14 - 811.29 341.89 342.45 0.56 0.0 -0.3 0.00470 BK 470 343.17 343.7 0.5 470 343.17 343.7 0.5 470.00 343.48 344.04 0.56 1003.39 343.45 343.98 0.53 0.0 0.3 -0.03460 460 343.11 343.6 0.5 460 343.11 343.6 0.5 460.00 343.24 343.79 0.55 1074.16 343.25 343.77 0.52 0.0 0.1 0.01120 BJ 120 343.03 343.5 0.5 120 343.02 343.5 0.5 120.00 343.12 343.56 0.44 1155.31 343.16 343.56 0.40 0.0 0.1 0.04116 116 342.69 343.2 0.5 116 342.68 343.2 0.5 116.00 342.75 343.28 0.53 1241.18 342.75 343.23 0.48 0.0 0.1 0.00114 114 341.65 342.1 0.4 114 341.63 342.1 0.5 114.00 341.25 341.97 0.72 1296.21 341.25 341.97 0.72 0.0 -0.4 0.00112 BI 339.9 340.3 0.4 112 339.90 340.3 0.4 112 339.74 340.3 0.6 112.00 339.90 340.30 0.40 15 - 1472.85 339.90 340.30 0.40 -0.2 0.0 0.00 FEMA FIS Data Effective HEC-RAS (LOMR November 20, 2015) Duplicate Effective HEC-RAS Corrected Effective/Existing HEC-RAS Proposed HEC-RAS Section Distance1 FP (NAVD- 88) FW FW-FP
[2] [3]
Section FP FW FW-FP Section FP FW FW-FP Section
[4]
FP FW FW-FP Section FP FW FW-FP
Duplicate
Effective
FP -
Effective
FP
[3]-[2]
Corrected
Effective
FP -
Effective
FP
[4]-[2]
Prop FP -
Corr
Effective
FP
[5]-[4]
[5]
Prepared By: SFR:TER/vs/C19500/WR/FEMA/CLOMR/CompiledRpt/19516.006 RICK – Water Resources Division 1-13-25
12 6.0 DIGITAL DATA
An AutoCAD file including all cross sections and floodplain/floodway information as well as the executable hydraulic models have been submitted with this CLOMR. They can be found with the digital data in Appendix 15. All digital data is submitted on the following horizontal datum:

Horizontal: NAD 83, California State Plane Zone VI (feet) APPENDIX 1
FEMA MT-2 Forms
FEMA FORM FF-206-FY-21-100 (formerly 086-0-27)
(01/21)
MT-2 FORM 1 Page 1 of 3
OMB Control Number: 1660-0016
Expiration: 1/31/2024

DEPARTMENT OF HOMELAND SECURITY
Federal Emergency Management Agency

OVERVIEW & CONCURRENCE FORM

PAPERWORK BURDEN DISCLOSURE NOTICE
Public reporting burden for this form is estimated to average 1 hours per response. The burden estimate includes the time for reviewing instructions, searching existing data sources, gathering and maintaining the needed data, and completing, reviewing, and submitting the form.

You are not required to respond to this collection of information unless it displays a valid OMB control number. Send comments regarding the accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, Department of Homeland Security, Federal Emergency Management Agency, 500 C Street, SW, Washington, DC 20472 , Paperwork Reduction Project (1660-0016). Submission of the form is required to obtain or retain benefits under the National Flood Insurance Program. Please do not send your completed survey to the above address.

PRIVACY ACT STATEMENT
AUTHORITY: The National Flood Insurance Act of 1968, Public Law 90-448, as amended by the Flood Disaster Protection Act of 1973, Public Law 93-234.

PRINCIPAL PURPOSE(S): This information is being collected for the purpose of determining an applicant's eligibility to request changes to National Flood Insurance Program (NFIP) Flood Insurance Rate Maps (FIRM).

ROUTINE USE(S): The information on this form may be disclosed as generally permitted under 5 U.S.C § 552a(b) of the Privacy Act of 1974, as amended. This includes using this information as necessary and authorized by the routine uses published in DHS/FEMA/NFIP/LOMA-1 National Flood Insurance Program (NFIP); Letter of Map Amendment (LOMA) February 15, 2006, 71 FR 7990.

DISCLOSURE: The disclosure of information on this form is voluntary; however, failure to provide the information requested may delay or prevent FEMA from processing a determination regarding a requested change to a (NFIP) Flood Insurance Rate Maps (FIRM).

A. REQUESTED RESPONSE FROM DHS-FEMA
This request is for a (check one):

CLOMR: A letter from DHS-FEMA commenting on whether a proposed project, if built as proposed, would justify a map revision, or proposed hydrology changes (See 44 CFR Ch. 1, Parts 60, 65 & 72). All CLOMRs require documentation of compliance with the Endangered Species Act. Refer to the Instructions for details.

LOMR: A letter from DHS-FEMA officially revising the current NFIP map to show the changes to floodplains, regulatory floodway or flood elevations. (See 44 CFR Ch. 1, Parts 60, 65 & 72).

B. OVERVIEW

1. The NFIP map panel(s) affected for all impacted communities is (are):

Community No. Community Name State Map No. Panel No. Effective Date

2. a. Flooding Source:
b. Types of Flooding: Riverine Coastal Shallow Flooding (e.g., Zones AO and AH) Alluvial Fan Lakes Other (Attach Description)

3. Project Name/Identifier:

4. FEMA zone designations (choices: A, AH, AO, A1-A30, A99, AE, AR, V, V1-V30, VE, B, C, D, X) a. Effective:
b. Revised:
060703 SANTEE, CITY OF CA 06073C 1651G 5/16/2022
Zone AE
Zone AE
FEMA FORM FF-206-FY-21-100 (formerly 086-0-27)
(01/21)
MT-2 FORM 1 Page 2 of 3

5. Basis for Request and Type of Revision:
a. The basis for this revision request is (check all that apply) Physical Change Improved Methodology/Data Regulatory Floodway Revision Base Map Changes Coastal Analysis Hydraulic Analysis Hydrologic Analysis Corrections Weir-Dam Changes Levee Certification Alluvial Fan Analysis Natural Changes New Topographic Data Other (Attach Description)
Note: A photograph and narrative description of the area of concern is not required, but is very helpful during review. b. The area of revision encompasses the following structures (check all that apply) Structures: Channelization Levee/Floodwall Bridge/Culvert Dam Fill Other (Attach Description)

6. Documentation of ESA compliance is submitted (required to initiate CLOMR review). Please refer to the instructions for more information.

C. REVIEW FEE
Has the review fee for the appropriate request category been included? Yes No, Attach Explanation
Fee amount: $
- Please see the DHS-FEMA Web site at http://www.fema.gov/forms-documents-and-software/floodmap-related-fees for Fee Amounts and Exemptions.

D. SIGNATURES

1. REQUESTOR'S SIGNATURE
All documents submitted in support of this request are correct to the best of my knowledge. I understand that any false statement may be punishable by fine or imprisonment under Title 18 of the United States Code, Section 1001.

Name: Company:

Mailing Address: Daytime Telephone: Fax No.:

E-mail Address:

Signature of Requestor (required):

Date:

2. COMMUNITY CONCURRENCE
As the community official responsible for floodplain management, I hereby acknowledge that we have received and reviewed this Letter of Map Revision (LOMR) or conditional LOMR request. Based upon the community's review, we find the completed or proposed project meets or is designed to meet all of the community floodplain management requirements, including the requirements for when fill is placed in the regulatory floodway, and that all necessary Federal, State, and local permits have been, or in the case of a conditional LOMR, will be obtained. For Conditional LOMR requests, the applicant has documented Endangered Species Act (ESA) compliance to FEMA prior to FEMA's review of the Conditional LOMR application. For LOMR requests, I acknowledge that compliance with Sections 9 and 10 of the ESA has been achieved independently of FEMA's process. For actions authorized, funded, or being carried out by Federal or State agencies, documentation from the agency showing its compliance with Section 7(a)(2) of the ESA will be submitted. In addition, we have determined that the land and any existing or proposed structures to be removed from the SFHA are or will be reasonably safe from flooding as defined in 44CFR 65.2(c), and that we have available upon request by FEMA, all analyses and documentation used to make this determination.

Community Official's Name and Title:

Mailing Address: Community Name:

Daytime Telephone: Fax No.:

E-mail Address:

Community Official's Signature (required): Date:
7,000
Shavger Rekani Rick Engineering Company
5620 Friars Road
San Diego, CA 92110
619-291-0707 619-291-4165
[email protected]
Carl Schmitz,Director of Engineering
Santee
10601 Magnolia Ave.

Santee, CA 92071 619-258-4100
[email protected]
FEMA FORM FF-206-FY-21-100 (formerly 086-0-27)
(01/21)
MT-2 FORM 1 Page 3 of 3

3. CERTIFICATION BY REGISTERED PROFESSIONAL ENGINEER AND/OR LAND SURVEYOR This certification is to be signed and sealed by a licensed land surveyor, registered professional engineer, or architect authorized by law to certify elevation information data, hydrologic and hydraulic analysis, and any other supporting information as per NFIP regulations paragraph

65.2(b) and as described in the MT-2 Forms Instructions. All documents submitted in support of this request are correct to the best of my knowledge. I understand that any false statement may be punishable by fine or imprisonment under Title 18 of the United States Code, Section 1001.

Certifier's Name: License No.: Expiration Date:

Company Name:

Telephone No.: Fax No.:

E-mail Address:

Mailing Address:

Signature: Date:

Ensure the forms that are appropriate to your revision request are included in your submittal.

Form Name and (Number)
Riverine Hydrology and Hydraulics Form (Form 2)
Riverine Structures Form (Form 3)
Coastal Analysis Form (Form 4)
Coastal Structures Form (Form 5)
Alluvial Fan Flooding Form (Form 6)
Required if …
New or revised discharges or watersurface elevations
Channel is modified, addition/revision of
bridge/culverts, addition/revision of
levee/floodwall, addition/revision of dam
New or revised coastal elevations
Addition/revision of coastal structure
Flood control measures on alluvial fans Seal (Optional) Shavger Rekani 90893 03/01/2026
Rick Engineering Company
619-291-0707 619-291-4165
[email protected]
5620 Friars Road
San Diego, CA 92110
FEMA FORM FF-206-FY-21-101 (formerly 086-0-27A)
(01/21)

Page 1 of 3 ends
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