ATTACHMENT D.17 AppendixG-Geotechnical-Evaluation — San Marcos City Council, September 9, 2025

PRELIMINARY PRELIMINARY GEOTECHNICAL Evaluation
FOR

PROPOSED RESIDENTIAL DEVELOPMENT
APN 220-210-49-00

NORTHEAST OF WOODWARD & MISSION

SAN MARCOS , CALIFORNIA

REPARED FOR

Pacific Group
P.O. Box 9890
Rancho Santa Fe, Ca 92067

REPARED BY

GEO TEK , INC .
1384 POINSETTIA AVENUE , SUITE A
VISTA , CALIFORNIA 92081

PROJECT NO. 3575 -SD MAY 16, 2019

GEOTECHNICAL | ENVIRONMENTAL | MATERIALS

May 16, 2019
Project No. 3575-SD
Pacific Group
P.O. Box 9890
Rancho Santa Fe, Ca 92067

Attention: Mr. Reza Shera

Subject: Preliminary Geotechnical Evaluation
APN 220-210-49-00
Northeast of Woodward & Mission
San Marcos, California

Dear Mr. Shera:

We are pleased to provide herein the results of our preliminary geotechnical evaluation for the subject project located in the C ity of San Marcos, California. This report presents the results of our evaluation and p rovides preliminary geotechnical recommendations for earthwork, foundation design, a nd construction. In our opinion, site development appears feasible from a geotechnic al viewpoint provided that the recommendations included herein are incorporated in to the design and construction phases of site development. The opportunity to be of serv ice is sincerely appreciated. If you should have any questions, please do not hesitate to call our office.

Respectfully submitted,
GeoTek, Inc.

Christopher D. Livesey
PG 9584, Exp. 05/30/21
Project Geologist

Benjamin R. Grenis
RCE 83971, Exp. 09/30/19
Project Engineer

Distribution: (1) Addressee via email
PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page i

TABLE OF CONTENTS

1. PURPOSE AND SCOPE OF SERVICES ..................................................................................................... . 1

2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT .................................................. .................. 1

2.1 Site Description ..................................................................................................... ................................ 1

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

3. FIELD EXPLORATION AND LABORATORY TESTING ...................................................................... 3

3.1 Field Exploration ..................................................................................................... ............................... 3

3.2 Percolation And Infiltration Testing .................................................. ................................................... .... 3

3.3 Laboratory Testing ..................................................................................................... ............................ 4

4. GEOLOGIC AND SOILS CONDITIONS .................................................................................................... 4

4.1 Regional Setting ..................................................................................................... ................................ 4

4.2 EARTH MATERIALS .................................................. ................................................... ......................... 5

4.2.1 Undocumented Fill ..................................................................................................... ............................ 5

4.2.2 Colluvium ..................................................................................................... ......................................... 5

4.2.3 Bedrock .................................................. ................................................... ........................................... 5

4.3 SURFACE WATER AND GROUNDWATER ............................................................................................. 6

4.3.1 Surface Water ..................................................................................................... .................................. 6

4.3.2 Groundwater ..................................................................................................... .................................... 6

4.4 EARTHQUAKE HAZARDS ..................................................................................................... ................ 6

4.4.1 Surface Fault Rupture ..................................................................................................... ....................... 6

4.4.2 Liquefaction/Seismic Settlement ................................................... ................................................... ........ 6

4.4.3 Other Seismic Hazards ..................................................................................................... ..................... 7

5. CONCLUSIONS AND RECOMMENDATIONS .................................................. ..................................... 7

5.1 General ..................................................................................................... ............................................ 7

5.2 EARTHWORK CONSIDERATIONS .................................................. ................................................... ... 7

5.2.1 General ..................................................................................................... ............................................ 7

5.2.2 Site Clearing and Preparation ..................................................................................................... ............ 8

5.2.3 Remedial Grading ..................................................................................................... ............................. 8

5.2.4 Engineered Fill ..................................................................................................... .................................. 9

5.2.5 Slopes ..................................................................................................... .............................................. 9

5.2.6 Excavation Characteristics ..................................................................................................... ................. 9

5.2.7 Shrinkage and Bulking ..................................................................................................... .................... 10

5.2.8 Trench Excavations and Backfill .................................................. ................................................... ...... 10

5.3 DESIGN RECOMMENDATIONS ..................................................................................................... ..... 11

5.3.1 Stormwater Infiltration ..................................................................................................... .................... 11

5.3.2 Foundation Design Criteria ..................................................................................................... .............. 11

5.3.3 Underslab Moisture Membrane ................................................... ................................................... ...... 13

5.3.4 Miscellaneous Foundation Recommendations ........................................................................................ 14

5.3.5 Foundation Set Backs ................................................... ................................................... ..................... 15

5.3.6 Seismic Design Parameters .................................................. ................................................... ............. 15

5.3.7 Soil Corrosivity ..................................................................................................... ................................ 16

5.3.8 Soil Sulfate Content ..................................................................................................... ........................ 16

5.4 RETAINING WALL DESIGN AND CONSTRUCTION ............................................................................. 16

5.4.1 General Design Criteria ..................................................................................................... ................... 16

5.4.2 Wall Backfill and Drainage .................................................. ................................................... ............. 17

5.4.3 Restrained Retaining Walls .................................................. ................................................... ............. 18 PACIFIC GROUP Project No. 3575-SD
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TABLE OF CONTENTS

5.4.4 Soil Nail Wall ..................................................................................................... ................................. 19

5.5 POST CONSTRUCTION CONSIDERATIONS .................................................. ...................................... 19

5.5.1 Landscape Maintenance and Planting ................................................................................................... 1 9

5.5.2 Drainage ..................................................................................................... ........................................ 19

5.6 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS .................................................. .................... 20

6. LIMITATIONS ..................................................................................................... ............................................ 20

7. SELECTED REFERENCES ..................................................................................................... ....................... 22

ENCLOSURES
Figure 1 – Site Location Map
Figure 2 – Geotechnical Map

Appendix A – Exploratory Trench Logs and Seismic Refraction Survey Appendix B – Results of Laboratory Testing
Appendix C – General Earthwork Grading Guidelines

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1. PURPOSE AND SCOPE OF SERVICES
The purpose of this study was to evaluate the geote chnical conditions on the site. Services provided for this study included the following:

 Research and review of available geologic and geote chnical data, and general information pertinent to the site.
 Site exploration consisting of surface field mapping by a Professional Geologist from our firm.
 Three (3) seismic refraction line “surveys” were co mpleted to help evaluate subsurface conditions and excavation characteristics on the property.  Excavation of seven (7) exploratory trenches onsite and collection of bulk soil samples for subsequent laboratory testing.
 Laboratory testing of the soil samples collected during the field investigation.  Review and evaluation of site seismicity, and
 Compilation of this geotechnical report which prese nts our findings of pertinent site geotechnical conditions and geotechnical recommendations for site development.

2. SITE DESCRIPTION AND PROPOSED DEVELOPMENT

2.1 Site Description

The subject project site is located northeast of Woo dward Street and East Mission Road in the City of San Marcos, California (see Figure 1). The site is generally bounded to the west by Woodward Street, to the north by a natural slope, to the east by residential development, and to the south by a natural slope descending to East Mission Road. The site is located in a hillside setting with topography generally ascending from th e north, west, and south site boundaries to the eastern boundary of the site. Site surface con ditions generally consist of dense natural vegetation and outcrops of boulders. The site area appears vacant, with a local area which appears to have been cut to a level pad. Access is achieved via an unpaved road off Woodward PACIFIC GROUP Project No. 3575-SD
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Street and wraps around the west side of the slope to a localized level pad. Fill areas appear to be attributed to the access road and level pad.

Total relief across the site is on the order of 100 ± feet, with surface drainage directed towards the southwest. Topographically, the high points on the property are located toward the northeast and northwest corners (elevation of rough ly 695 feet msl), and the low point is toward the southwestern corner of the property. St eep natural gradients exist in the central, northeastern and northwestern portions of the prope rty. These slope areas are locally as steep as 1:1 (horizontal to vertical) in gradient a nd expose Monzogranite (granitic) bedrock materials. Relatively small earthen fill slope are as (unmapped) were also noted along the access road and edges of the level pad.

2.2 Proposed Development
Based on review of the conceptual site plan for the project site prepared by Excel Engineering, unknown date, a multi-family residential developmen t with a total of 22 buildings are proposed for the site. Fifteen buildings are 3-stories and seven buildings are 2-stories. Access to the development will be provided off Woodward Street and wrap around the hillside. Grading improvements generally consist of a 30 foot tall cu t slope along the east property line and a 12 foot high fill slope inclined at a 2:1 horizontal:v ertical (H:V) with an 8 foot tall concrete- masonry-unit retaining wall at the bottom of the fi ll slope. In addition, a 15 foot soil nail wall with a 25 foot tall cut slope above, accommodates t he entry road to the development. The plan reviewed depicts several other smaller CMU ret aining walls in addition to those stated above. Associated improvements are anticipated to consist of a water quality control basin and tree wells, wet and dry utilities, hardscape, s tructural pavement, and landscaping. A copy of the plan provided is used as the base for the Ge otechnical Map (Figure 2) included with this report.

As site development planning progresses and plans b ecome available, the plans should be provided to GeoTek for review and comment. Additio nal geotechnical field exploration, laboratory testing and engineering analyses may be necessary in order to provide specific earthwork recommendations and geotechnical design p arameters for actual site development plans.

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3. FIELD EXPLORATION AND LABORATORY TESTING

3.1 Field Exploration

Our field exploration was conducted between April 2 6 and May 1, 2019 and consisted of a site reconnaissance, excavation of seven exploratory tes t pits, collection of loose bulk soil samples for subsequent laboratory testing, three seismic re fraction surveys by a specialty consultant, and two field percolation test borings. A Professi onal Geologist from our firm field mapped the site from a geologic perspective, visually logg ed the test pits, and collected soil samples for laboratory analysis. Approximate locations of expl oration locations are presented on the Geotechnical Map, Figure 2. A description of mater ial encountered in the exploratory test pits and a copy of the seismic refraction report is included in Appendix A.

3.2 Percolation And Infiltration Testing
Borings PB-1 and PB-2, were advanced with a hand au ger to practical refusal at a depth of approximately 12-inches below existing ground. Fol lowing completion of the borings, percolation testing was performed in borings PB-1, and PB-2 by a representative from our firm in general conformance with the City of San Marcos BMP Design Manual. The boreholes were presoaked overnight and the testing was performed o n the following day. Percolation testing was performed by adding potable water to the boring s, recording the initial depth to water and allowing the water to percolate for 30 minutes and the depth to water was measured. Water was generally added to each boring following each r eading increment. In general, the percolation testing was performed for approximately 6 hours to allow rates to stabilize.

Results of the final percolation increment were use d to calculate an infiltration rate in inches per hour via the Porchet method.

For design of shallow infiltration basins, converti ng percolation rates to infiltration rates via the Porchet method is generally acceptable and appropriate, as this method factors out the sidewall component of the percolation results and represents the bottom conditions of a shallow basin (infiltration). Therefore, the percolation data for borings PB-1 and PB-2 were converted via the Porchet method. This method is consistent with the guidelines referenced in the City of San Marcos BMP Design Manual. Results of our infiltrat ion analysis without a factor of safety are presented in the follow table for each of the test areas.

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Location Depth
(inches )
Inflitration Rate
(inches per hour) *
PB -1 12 0. 68
PB -2 13 0.70
* Rate was converted to an infiltration rate via t he Porchet method

Copies of the percolation data sheets and an infilt ration conversion sheet are included in Appendix B.

The material exposed along the boring sidewalls and at the bottom of each test area were native soils. The tests performed and reported are indicative of the native soils. If the sidewalls and/or bottom of any of the proposed infiltration a reas expose engineered fill, additional infiltration testing should be performed. Also, th e granitic bedrock that underlies this site at shallow depth will likely resist infiltration stormwater disposal possibilities.

Over the lifetime of the storm water disposal areas , the percolation rates may be affected by silt build up and biological activities, as well as local variations in soil conditions. An appropriate factor of safety used to compute the design percola tion rate should be considered at the discretion of the design engineer and acceptance of the plan reviewer.

3.3 Laboratory Testing
Laboratory testing was performed on bulk soil sampl es collected during the field explorations.

The purpose of the laboratory testing was to evalua te their physical and chemical properties for use in the engineering design and analysis. Re sults of the laboratory testing program, along with a brief description and relevant information r egarding testing procedures, are included in Appendix B.

4. GEOLOGIC AND SOILS CONDITIONS

4.1 Regional Setting
The subject property is located in the Peninsular R anges geomorphic province. The Peninsular Ranges province is one of the largest geomorphic un its in western North America. Basically, it extends roughly 975 miles from the north and northe asterly adjacent the Transverse Ranges geomorphic province to the tip of Baja California. This province varies in width from about 30 to 100 miles. It is bounded on the west by the Pac ific Ocean, on the south by the Gulf of California and on the east by the Colorado Desert Province.

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The Peninsular Ranges are essentially a series of n orthwest-southeast oriented fault blocks.

Several major fault zones are found in this provinc e. The Elsinore Fault zone and the San Jacinto Fault zones trend northwest-southeast and a re found in the near the middle of the province. The San Andreas Fault zone borders the n ortheasterly margin of the province. No faults are shown in the immediate site vicinity on the map reviewed for the area.

4.2 EARTH MATERIALS
A brief description of the earth materials encounte red during our subsurface exploration is presented in the following sections. Based on our field observations and review of published geologic maps the subject site area is locally unde rlain by sporadic undocumented fill materials, colluvium, and Cretaceous age crystalline bedrock.

4.2.1 Undocumented Fill
Some undocumented fill soils were locally observed in the vicinity of the level pad in the southern vicinity of the site and along the unpaved access road that wraps around the western side of the site. As observed, the undocumented fi ll generally consisted of silty sand with some cobbles and small boulders. Other areas of undocum ented fill (unmapped) are also likely present on the site. Undocumented fill soils are n ot considered suitable for support of structural site improvements, but may be re-used as engineered fill if properly placed.

4.2.2 Colluvium (not mapped)
Colluvial soils are anticipated to be present in dr ainage swales or in localized areas on the site in relatively lower gradient slopes. Colluvial mat erials were not directly observed, however are anticipated to generally consist of clayey sand s that are organic in nature. In general, the colluvium is likely thinner (i.e. bedrock is shallo wer) where slope gradients are steeper and in steep areas, might not be present at all.

4.2.3 Bedrock
The most recent regional geologic map showing the o verall site geology (Kennedy, 2007), shows Mesozoic-aged meta-sedimentary bedrock at the surface across the site, however based on our site evaluation Cretaceous age plutonic bedr ock tonalite-monzogranite (granite) was observed across the property, with outcrops and par tially exposed core stones of bedrock materials. In the exploratory trenches, weathered to less weathered tonalite bedrock materials were encountered and observed to excavate primarily as red brown silty sand with gravel, cobble, and small boulder size fragments. The granitic bedrock materials were also observed on the adjacent surrounding properties, most notably to the east, north and south.

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Anticipated bedrock excavation characteristics are discussed in a later section of this report.

Descriptions of the bedrock materials as encountere d in our exploratory trenches are shown on the exploratory trench logs included in Appendix A, and the results of the subsurface seismic refraction surveys are also included in Appendix A.

4.3 SURFACE WATER AND GROUNDWATER

4.3.1 Surface Water
Surface water was not observed during our site visi t. If encountered during earthwork construction, surface water on this site is the res ult of precipitation or possibly some minor surface run-off from immediately surrounding proper ties. Overall site area drainage is in a westerly direction, toward Woodward Street. Provisi ons for surface drainage will need to be accounted for by the project civil engineer.

4.3.2 Groundwater
Groundwater is not anticipated to be within 50 feet of the ground surface at the subject site and is not anticipated to be a factor in site devel opment. Localized perched groundwater could be present, but is also not anticipated to be a factor in site development.

4.4 EARTHQUAKE HAZARDS

4.4.1 Surface Fault Rupture
The geologic structure of the entire southern Calif ornia area is dominated mainly by northwest-trending faults associated with the San A ndreas system. The site is in a seismically active region. No active or potentially active fau lt is known to exist at this site nor is the site situated within an “Alquist-Priolo” Earthquake Fault Zone or a Special Studies Zone (Br yant and Hart, 2007). No faults are identified on the readi ly available geologic maps that were reviewed by this firm for the immediate study area.

4.4.2 Liquefaction/Seismic Settlement
Liquefaction describes a phenomenon in which cyclic stresses, produced by earthquake- induced ground motion, create excess pore pressures in relatively cohesionless soils. These soils may thereby acquire a high degree of mobility , which can lead to lateral movement, sliding, consolidation and settlement of loose sedi ments, sand boils and other damaging deformations. This phenomenon occurs only below th e water table, but, after liquefaction has PACIFIC GROUP Project No. 3575-SD
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developed, the effects can propagate upward into ov erlying non-saturated soil as excess pore water dissipates.

The factors known to influence liquefaction potenti al include soil type and grain size, relative density, groundwater level, confining pressures, an d both intensity and duration of ground shaking. In general, materials that are susceptibl e to liquefaction are loose, saturated granular soils having low fines content under low confining pressures.

The liquefaction potential and seismic settlement p otential on this site is considered to be negligible, due to shallow bedrock and absence of a shallow groundwater table.

4.4.3 Other Seismic Hazards
Evidence of ancient landslides or slope instabiliti es at this site was not observed during our investigation. Thus, the potential for landslides is considered negligible. Rockfall potential should be further assessed when site development pl ans become available and during grading construction.

The potential for secondary seismic hazards such as seiche and tsunami is considered to be remote due to site elevation and distance from an open body of water.

5. CONCLUSIONS AND RECOMMENDATIONS

5.1 General
Development of the site appears feasible from a geo technical viewpoint provided that the following recommendations are incorporated in the d esign and construction phases of the development. The following sections present genera l recommendations for currently anticipated site development plans.

5.2 EARTHWORK CONSIDERATIONS

5.2.1 General
Earthwork and grading should be performed in accord ance with the applicable grading ordinances of the City of San Marcos, the 2016 Cali fornia Building Code (CBC), and recommendations contained in this report. The Grad ing Guidelines included in Appendix C outline general procedures and do not anticipate al l site specific situations. In the event of PACIFIC GROUP Project No. 3575-SD
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conflict, the recommendations presented in the text of this report should supersede those contained in Appendix C.

5.2.2 Site Clearing and Preparation
Site preparation should start with removal of delet erious materials and vegetation. These materials should be disposed of properly off site. Any existing underground improvements, utilities and trench backfill should also be remove d or be further evaluated as part of site development operations.

5.2.3 Remedial Grading
Prior to placement of fill materials, the upper los e and compressible materials should be removed for structural site areas. Removal depths in areas of existing undocumented fill, colluvium and highly weathered bedrock are estimate d to be up to approximately 5 feet in areas of mapped existing fill. The lateral extent of removals beyond the outside edge of all settlement sensitive structures/foundations should be equivalent to that vertically removed.

Depending on actual field conditions encountered du ring grading, locally deeper and/or shallower areas of removal may be necessary.

At a minimum, the cut portion(s) of any building pad areas in site bedrock or natural material(s) should be overexcavated a minimum of three (3) feet below finish pad grade or a minimum of two (2) feet below the bottom of the deepest propos ed footing, whichever is deeper.

Overexcavations should extend a minimum of five (5) feet outside the proposed building envelope(s). The intent of the recommended overexc avation is to support the improvements on engineered fill with relatively uniform engineer ing characteristics and decrease the potential for differential settlement.

Removal bottom gradients should be sloped towards t he street to reduce potential long term perched groundwater conditions. The bottom of all removals should be scarified to a minimum depth of six (6) inches, brought to at or above opt imum moisture content, and then compacted to minimum project standards prior to fill placemen t. The remedial excavation bottoms should be observed by a GeoTek representative prior to sca rification. The resultant voids from remedial grading/overexcavation should be filled wi th materials placed in general accordance with Section 5.2.4 Engineered Fill of this report.

Depending on final proposed grades relative to the less weathered bedrock materials, additional excavation may be required to enable utility trench excavation with typically employed equipment. If this is desired, such excavation wou ld extend to the bottom of the deepest proposed utility trench bedding zone.

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5.2.4 Engineered Fill
Onsite materials are generally considered suitable for reuse as engineered fill provided they are free from vegetation, roots, debris, and rock/concrete or hard lumps greater than six (6) inches in maximum dimension. The earthwork contractor sho uld have the proposed excavated materials to be used as engineered fill at this pro ject approved by the soils engineer prior to placement.

Engineered fill materials should be moisture condit ioned to at or above optimum moisture content and compacted in horizontal lifts not excee ding 8 inch in loose thickness to a minimum relative compaction of 90% as determined in accorda nce with laboratory test procedure ASTM D 1557.

If fill is being placed on slopes steeper than 5:1 (h:v), the fill should be properly benched into the existing slopes and a sufficient size keyway sh all be constructed in accordance with grading guidelines presented in Appendix C.

5.2.5 Slopes
Proposed cut or fill slopes will need to be further evaluated when site development plans become more refined. Fill slopes constructed at gr adients of 2:1 (horizontal:vertical), in accordance with industry standards, are anticipated to be both grossly and surficially stable.

However, some fill soils derived from onsite materi als may be sandy and have very low cohesion. These materials are erodible and the use of jute mesh or similar products designed to enhance surficial stability may be necessary until plant growth is established.

Cut slopes constructed at gradients of 2:1 (horizon tal:vertical) or possibly steeper exposing bedrock materials are also anticipated to be grossl y and surficially stable, but should be further evaluated based on anticipated and exposed structur e (joints/fractures). Future landscaping on cut slopes exposing relatively unweathered bedrock materials could be difficult with the possibility of little plant growth due to the hard/ dense nature of the bedrock. Replacement stability fills may be considered to enhance the plantability of the proposed cut slopes.

5.2.6 Excavation Characteristics
Excavations in the onsite undocumented fill, colluv ium and weathered bedrock materials can generally be accomplished with heavy-duty earthmovi ng or excavating equipment in good operating condition. Less weathered bedrock materi als are also likely to be encountered at depth and could locally require special techniques to excavate.

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Seismic refraction data for the areas evaluated see ms to generally indicate that excavations on the order of roughly 6 to 19 feet should be excavat able with conventional earthmoving equipment with some exceptions to core stones (See Appendix A). Core stones and boulders were also noted in the seismic refraction data, and also observed on the site, which could necessitate special excavation techniques if encoun tered during site earthwork. A summary of bedrock hardness and recommendations is presented i n Appendix A of this report (Subsurface Surveys, 2019).

Based on preliminary review of the current developm ent plan for the project site and the anticipated depths of cut in localized areas, some blasting will likely be required to achieve the design grades or utility construction in some areas . The ultimate need for special excavation techniques and/or blasting will only be known durin g rough earthwork construction. In addition, materials generated from these special ex cavation techniques will likely be difficult to place in structural fills due to variations in size and wear on equipment. The need to trench for underground utilities should also be considered when rough grading is taking place for a project underlain by potentially very hard bedrock. Over-e xcavating streets to the depth of the anticipated deepest underground utility trench shou ld be considered. Additional review and interpretation with respect to rock hardness is rec ommended by the project grading and utility construction contractors.

5.2.7 Shrinkage and Bulking
Several factors will impact earthwork balancing on the site, including bedrock bulking, undocumented fill and colluvium shrinkage, trench s poil from utilities and footing excavations, as well as the accuracy of topography.

Shrinkage and bulking are largely dependent upon th e degree of compactive effort achieved during construction. For planning purposes, a shri nkage factor ranging from 5 to 15 percent may be considered for the colluvium and undocumented fill materials requiring removal and re- compaction. Bedrock bulking could range from 0 to 20 percent. Subsidence should not be a factor on the subject site if removals are complete d down to the recommended depths to expose bedrock materials. Site balance areas shoul d be available in order to adjust project grades, depending on actual field conditions at the conclusion of site earthwork construction.

5.2.8 Trench Excavations and Backfill
Temporary excavations within the onsite materials should be stable at 1:1 inclinations for short durations during construction, and where cuts do no t exceed 10 feet in height. Temporary cuts to a maximum height of 4 feet can be excavated vertically.

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Trench excavations should conform to Cal-OSHA regul ations. The contractor should have a competent person, per OSHA requirements, on site during construction to observe conditions and to make the appropriate recommendations.

Utility trench backfill should be compacted to at l east 90% relative compaction of the maximum dry density as determined per ASTM D 1557. Under-slab trenches should also be compacted to project specifications.

Onsite materials may not be suitable for use as bed ding material, but should be suitable as backfill provided particles larger than 6± inches are removed.

Compaction should be achieved with a mechanical com paction device. Ponding or jetting of trench backfill is not recommended. If backfill so ils have dried out, they should be thoroughly moisture conditioned prior to placement in trenches.

5.3 DESIGN RECOMMENDATIONS

5.3.1 Stormwater Infiltration
Many factors control infiltration of surface waters into the subsurface, such as consistency of native soils and bedrock, geologic structure, fill consistency, material density differences, and existing groundwater conditions. Based on our revie w of the conceptual plan, a stormwater quality control basin is located above an approxima te 5-foot fill slope. In consideration of the site setting located in a hillside topographic sett ing, the proposed stormwater quality control basin constructed as engineered fill over dense gra nitic bedrock (a significant density increase), and the adjacent residential property downslope, in filtration of stormwater into the subsurface is not recommended from a geotechnical perspective. Stormwater quality control basins should be constructed with an impermeable liner along the sides and bottom.

5.3.2 Foundation Design Criteria
Preliminary foundation design criteria, in general conformance with the 2016 CBC, are presented herein. These are typical design criteri a and are not intended to supersede the design by the structural engineer.

Based on our visual classification of materials enc ountered onsite, soils near subgrade may be classified as “very low” expansive (EI<20) per ASTM D 4829. Additional laboratory testing should be performed at the completion of site gradi ng to verify the expansion potential and plasticity index, if necessary, of the subgrade soils.

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The following criteria for design of foundations are preliminary. Additional laboratory testing of the samples obtained during grading should be perfo rmed and final recommendations should be based on as-graded soil conditions.

MINIMUM DESIGN REQUIREMENTS FOR CONVENTIONALLY REINFORCED

FOUNDATIONS
DESIGN PARAMETER “Very Low”
Expansion Potential (0 ≤EI≤20)
Foun dation Embedment Depth or Minimum Perimeter
Beam Depth (inches below lowest adjacent finished
grade)
One -Story – 12
Two-Story – 18
Three -Story – 24
Minimum Foundation Width (Inches)*
Supporting One Floor - 12
Supporting Two Floors - 15
Supporting Three Floors - 18
Minimum Slab Thickness (actual) 4 inches
Minimum Slab Reinforcing No. 3 rebar 24” on -center, each way, placed in the middle one -third of the slab thickness
Minimum Footing Reinforcement Two No. 4 Reinforcing Bars, one (1) top and one (1) bot tom
Presaturation of Subgrade Soil (percent of optimum
moisture content) Minimum 100% to a depth of 12 inches *Code minimums per Table 1809.7 of the 2016 CBC sho uld be complied with.

It should be noted that the above recommendations a re based on soil support characteristics only. The structural engineer should design the sl ab and beam reinforcement based on actual loading conditions.

The following recommendations should be implemented into the design:

 An allowable bearing capacity of 2000 pounds per sq uare foot (psf) may be used for design of continuous and perimeter footings that me et the depth and width requirements in the table above. This value may be increased by 400 pounds per square foot for each additional 12 inches in depth and 200 pounds per square foot for each additional 12 inches in width to a maximum value of 3000 psf. Additionally, an increase of one-third may be applied when consid ering short-term live loads (e.g. seismic and wind loads).

 Based on our experience in the area, structural fou ndations may be designed in accordance with 2016 CBC, and to withstand a total settlement of 1 inch and maximum differential settlement of one-half of the total settlement over a horizontal distance of 40 feet. These values assum e that seismic settlement potential is not a significant constraint.

PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 13

 The passive earth pressure may be computed as an eq uivalent fluid having a density of 350 psf per foot of depth, to a maximum earth pr essure of 3000 psf for footings founded on engineered fill. A coefficient of frict ion between soil and concrete of

0.35 may be used with dead load forces. When combin ing passive pressure and frictional resistance, the passive pressure compone nt should be reduced by one- third.

 A grade beam, a minimum of 12 inches wide and 12 in ches deep, should be utilized across large entrances, however, the base of the gr ade beam should be at the same elevation as the bottom of the adjoining footings.

5.3.3 Underslab Moisture Membrane
A moisture and vapor retarding system should be pla ced below slabs-on-grade where moisture migration through the slab is undesirable. Guideli nes for these are provided in the 2016 California Green Building Standards Code (CALGreen) Section 4.505.2 and the 2016 CBC Section 1907.1

It should be realized that the effectiveness of the vapor retarding membrane can be adversely impacted as a result of construction related punctu res (e.g. stake penetrations, tears, punctures from walking on the vapor retarder placed atop the underlying aggregate layer, etc.). These occurrences should be limited as much as possible d uring construction. Thicker membranes are generally more resistant to accidental puncture that thinner ones. Products specifically designed for use as moisture/vapor retarders may al so be more puncture resistant. Although the CBC specifies a 6 mil vapor retarder membrane, it is GeoTek’s opinion that a minimum 10 mil membrane with joints properly overlapped and se aled should be considered, unless otherwise specified by the slab design professional.

Moisture and vapor retarding systems are intended t o provide a certain level of resistance to vapor and moisture transmission through the concret e, but do not eliminate it. The acceptable level of moisture transmission through the slab is to a large extent based on the type of flooring used and environmental conditions. Ultimately, the vapor retarding system should be comprised of suitable elements to limit migration o f water and reduce transmission of water vapor through the slab to acceptable levels. The s elected elements should have suitable properties (i.e. thickness, composition, strength a nd permeability) to achieve the desired performance level.

Moisture retarders can reduce, but not eliminate, m oisture vapor rise from the underlying soils up through the slab. Moisture retarder systems sho uld be designed and constructed in PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 14

accordance with applicable American Concrete Instit ute, Portland Cement Association, Post- Tensioning Concrete Institute, ASTM and California Building Code requirements and guidelines.

GeoTek does not practice in the field of moisture v apor transmission evaluation/migration, since that practice is not a geotechnical disciplin e. Therefore, we recommend that a qualified person, such as the flooring contractor, structural engineer, architect, and/or other experts specializing in moisture control within the buildin g be consulted to evaluate the general and specific moisture and vapor transmission paths and associated potential impact on the proposed construction. That person (or persons) should prov ide recommendations relative to the slab moisture and vapor retarder systems and for migrati on of potential adverse impact of moisture vapor transmission on various components of the str uctures, as deemed appropriate. In addition, the recommendations in this report and ou r services in general are not intended to address mold prevention; since we, along with geote chnical consultants in general, do not practice in the area of mold prevention. If specif ic recommendations addressing potential mold issues are desired, then a professional mold prevention consultant should be contacted.

We recommend that control joints be placed in two di rections spaced the numeric equivalent roughly 24 times the thickness of the slab in inche s (e.g. a 4 inch slab would have control joints at 96 inch [8 feet] centers). These joints are a w idely accepted means to control cracks and should be reviewed by the project structural engineer.

5.3.4 Miscellaneous Foundation Recommendations

 To reduce moisture penetration beneath the slab on grade areas, utility trenches should be backfilled with engineered fill, lean con crete or concrete slurry where they intercept the perimeter footing or thickened slab edge.

 Spoils from the footing excavations should not be p laced in the slab-on-grade areas unless properly compacted and tested. The excavati ons should be free of loose/sloughed materials and be neatly trimmed at the time of concrete placement.

 Unsuitable soil removals along the property lines w ill likely be restricted due to adjacent improvements. Special considerations will be required for foundation elements in these areas. Such considerations may i nclude deepening of foundations, reduced bearing capacity, or other measures. This issue should be further evaluated once site plans become available.

PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 15

5.3.5 Foundation Set Backs
Where applicable, the following setbacks should appl y to all foundations. Any improvements not conforming to these setbacks may be subject to lateral movements and/or differential settlements:

 The outside bottom edge of all footings should be s et back a minimum of H/3 (where H is the slope height) from the face of any descending slope. The setback should be at least 7 feet and need not exceed 40 feet.

 The bottom of all footings for structures near retaining walls should be deepened so as to extend below a 1:1 projection upward from the bottom inside edge of the wall stem. This applies to the existing retaining walls along the perimeter, if they are to remain.

 The bottom of any existing foundations for structur es should be deepened so as to extend below a 1:1 projection upward from the bottom of the nearest excavation.

5.3.6 Seismic Design Parameters
The site is located at approximately 33.1437 Latitu de and -117.1593 Longitude. Site spectral accelerations (Ss and S1), for 0.2 and 1.0 second p eriods for a risk targeted two (2) percent probability of exceedance in 50 years (MCER) were d etermined using the web interface provided by SEAOC/OSHPD ( https://seismicmaps.org ) to access the USGS Seismic Design Parameters. We have selected a Site Class “D” based on the anticipated depth of fill.

PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 16

SITE SEISMIC PARAMET ERS
Mapped 0.2 sec Period Spectral Acceleration, S s 1.019 g Mapped 1.0 sec Period Spectral Acceleration, S 1 0. 398 g Si te Coef ficient for Site Class “ D”, F a 1.0 92
Si te Coefficient for Site Class “ D”, F v 1. 603
Maximum Considered Earthquake ( MCE R) Spectral
Response Acceleration for 0.2 Second , S MS 1.119g
Maximum Considered Earthquake ( MCE R) Spectral
Response Acceleration for 1. 0 Second, S M1 0.639g
5% Damped Design Spectral Response
Acceleration Parameter at 0.2 Second, S DS 0.742g
5% Damped Design Spectral Response
Acceleration Parameter at 1 second, S D1 0.426g

5.3.7 Soil Corrosivity
The soil resistivity at this site was tested in the laboratory on samples collected during the field investigation. The results of the testing indicate that the onsite soils are not considered corrosive with current standards used by corrosion engineers. These characteristics are considered typical of soils commonly found in this area of southern California. We recommend that a corrosion engineer be consulted to provide r ecommendations for proper protection of buried metal at this site.

5.3.8 Soil Sulfate Content
The sulfate content was determined in the laborator y for a soil sample collected during the field investigation. The results indicate that the water soluble sulfate range is less than 0.1 percent by weight, which is considered “not applica ble” (negligible) as per Table 4.2.1 of ACI 318-11. Based upon the test results, no special mix design is required by Code to resist sulfate attack. As a minimum, additional testing should be completed subsequent to rough grading in order to confirm these initial results.

5.4 RETAINING WALL DESIGN AND CONSTRUCTION

5.4.1 General Design Criteria
Recommendations presented herein may apply to typic al masonry or concrete vertical retaining walls to a maximum height of 10 feet. Ad ditional review and recommendations should be requested for higher walls.

PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 17

Retaining wall foundations embedded a minimum of 18 inches into engineered fill or dense formational materials should be designed using an a llowable bearing capacity of 2000 psf. An increase of one-third may be applied when consideri ng short-term live loads (e.g. seismic and wind loads). The passive earth pressure may be com puted as an equivalent fluid having a density of 350 psf per foot of depth, to a maximum earth pressure of 3000 psf. A coefficient of friction between soil and concrete of 0.35 may be u sed with dead load forces. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third.

An equivalent fluid pressure approach may be used t o compute the horizontal active pressure against the wall. The appropriate fluid unit weigh ts are given in the table below for specific slope gradients of retained materials.

Surface Slope of Retained
Materials
(H:V)
Equivalent Fluid Pressure
(PCF)
Select Backfill*
Level 35
2:1 55
*Select backfill should consist of native or import ed sand other approved materials with an SE>20 and an EI<20.

The above equivalent fluid weights do not include o ther superimposed loading conditions such as expansive soil, vehicular traffic, structures, seismic conditions or adverse geologic conditions.

Additional lateral forces can be induced on retaini ng walls during an earthquake. For level backfill and a Site Class “D”, the minimum earthqua ke-induced force (F eq ) should be 13H 2
(lbs/linear foot of wall) for cantilever walls. Th is force can be assumed to act at a distance of

0.6H above the base of the wall, where “H” is the h eight of the retaining wall measured from the base of the footing (in feet). The 2016 CBC on ly requires the additional earthquake induced lateral force be considered on retaining wa lls in excess of six (6) feet in height; however, the additional force may be applied in des ign of lesser walls at the discretion of the wall designer.

5.4.2 Wall Backfill and Drainage
Wall backfill should include a minimum one (1) foot wide section of ¾ to 1-inch clean crushed rock (or approved equivalent). The rock should be placed immediately adjacent to the back of wall and extend up from the backdrain to within app roximately 12 inches of finish grade. The upper 12 inches should consist of compacted onsite materials. If the walls are designed using PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 18

the “select” backfill design parameters, then the “ select” materials shall be placed within the active zone as defined by a 1:1 (H:V) projection fr om the back of the retaining wall footing up to the retained surface behind the wall. Presence of other materials might necessitate revision to the parameters provided and modification of wall designs.

The backfill materials should be placed in lifts no greater than 8-inches in thickness and compacted to a minimum of 90% of the maximum dry de nsity as determined in accordance with ASTM Test Method D 1557. Proper surface drain age needs to be provided and maintained. Water should not be allowed to pond beh ind retaining walls. Waterproofing of site walls should be performed where moisture migration through the wall is undesirable.

Retaining walls should be provided with an adequate pipe and gravel back drain system to reduce the potential for hydrostatic pressures to d evelop. A 4-inch diameter perforated collector pipe (Schedule 40 PVC, or approved equiva lent) in a minimum of one (1) cubic foot per lineal foot of 3/8 to one (1) inch clean crushe d rock or equivalent, wrapped in filter fabric should be placed near the bottom of the backfill an d be directed (via a solid outlet pipe) to an appropriate disposal area.

Walls from two (2) to four (4) feet in height may be drained using localized gravel packs behind weep holes at 10 feet maximum spacing (e.g. approxi mately 1.5 cubic feet of gravel in a woven plastic bag). Weep holes should be provided or the head joints omitted in the first course of block extended above the ground surface. However, nuisance water may collect in front of the wall.

Drain outlets should be maintained over the life of the project and should not be obstructed or plugged by adjacent improvements.

5.4.3 Restrained Retaining Walls
Any retaining wall that will be restrained prior to placing backfill or walls that have male or reentrant corners should be designed for at-rest so il conditions using an equivalent fluid pressure of 60 pcf (select backfill), plus any appl icable surcharge loading. For areas having male or reentrant corners, the restrained wall design sh ould extend a minimum distance equal to twice the height of the wall laterally from the cor ner, or as otherwise determined by the structural engineer.

PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 19

5.4.4 Soil Nail Wall
At this time we understand that a soil nail wall is planned to accommodate the entry road into the site. We recommend that a wall designer and spe cialty contractor familiar with achievable strength parameters in the area be included in the development of parameters for the wall design. After preliminary design parameters have b een determined, a verification test program should be developed and implemented to verify the adequacy of the soil nail wall design.

5.5 POST CONSTRUCTION CONSIDERATIONS

5.5.1 Landscape Maintenance and Planting
Water has been shown to weaken the inherent strength of soil, and slope stability is significantly reduced by overly wet conditions. Po sitive surface drainage away from graded slopes should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Controlling surface drainage and runoff, and maintaining a suitable vegetation cover can minimize erosion. Plants selected for landscaping should be lightweight, deep-rooted types that require little water and are capable of surviving the prevailing climate.

Overwatering should be avoided. The soils should b e maintained in a solid to semi-solid state as defined by the materials Atterberg Limits. Care should be taken when adding soil amendments to avoid excessive watering. Leaching a s a method of soil preparation prior to planting is not recommended. An abatement program to control ground-burrowing rodents should be implemented and maintained. This is crit ical as burrowing rodents can decreased the long-term performance of slopes.

It is common for planting to be placed adjacent to structures in planter or lawn areas. This will result in the introduction of water into the ground adjacent to the foundation. This type of landscaping should be avoided. If used, then extre me care should be exercised with regard to the irrigation and drainage in these areas. Waterpr oofing of the foundation and/or subdrains may be warranted and advisable. We could discuss th ese issues, if desired, when plans are made available.

5.5.2 Drainage
The need to maintain proper surface drainage and su bsurface systems cannot be overly emphasized. Positive site drainage should be maint ained at all times. Drainage should not flow uncontrolled down any descending slope. Water shoul d be directed away from foundations PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 20

and not allowed to pond or seep into the ground. P ad drainage should be directed toward approved area(s) and not be blocked by other improvements.

It is the owner’s responsibility to maintain and clean drainage devices on or contiguous to their lot. In order to be effective, maintenance should be conducted on a regular and routine schedule and necessary corrections made prior to each rainy season.

5.6 PLAN REVIEW AND CONSTRUCTION OBSERVATIONS
We recommend that site grading, specifications, reta ining wall/shoring plans and foundation plans be reviewed by this office prior to construct ion to check for conformance with the recommendations of this report. Additional recomme ndations may be necessary based on these reviews. We also recommend that GeoTek repres entatives be present during site grading and foundation construction to check for pr oper implementation of the geotechnical recommendations. The owner/developer should have G eoTek’s representative perform at least the following duties:

 Observe site clearing and grubbing operations for p roper removal of unsuitable materials.
 Observe and test bottom of removals prior to fill placement.  Evaluate the suitability of on-site and import mate rials for fill placement, and collect soil samples for laboratory testing when necessary.
 Observe the fill for uniformity during placement including utility trenches.  Observe and test the fill for field density and relative compaction.  Observe and probe foundation excavations to confirm suitability of bearing materials.

If requested, a construction observation and compac tion report can be provided by GeoTek, which can comply with the requirements of the gover nmental agencies having jurisdiction over the project. We recommend that these agencies be no tified prior to commencement of construction so that necessary grading permits can be obtained.

6. LIMITATIONS
The scope of our evaluation is limited to the area explored that is shown on the Geotechnical Map (Figure 2). This evaluation does not and should in no way be construed to encompass any areas beyond the specific area of proposed construc tion as indicated to us by the client.

PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 21

Further, no evaluation of any existing site improve ments is included. The scope is based on our understanding of the project and the client’s needs, our proposal (Proposal No. P0200419- SD) dated February 14, 2019 and geotechnical engine ering standards normally used on similar projects in this region.

The materials observed on the project site appear t o be representative of the area; however, soil and bedrock materials vary in character betwee n excavations and natural outcrops or conditions exposed during site construction. Site conditions may vary due to seasonal changes or other factors. GeoTek, Inc. assumes no responsi bility or liability for work, testing or recommendations performed or provided by others.

Since our recommendations are based on the site con ditions observed and encountered, and laboratory testing, our conclusions and recommendat ions are professional opinions that are limited to the extent of the available data. Obser vations during construction are important to allow for any change in recommendations found to be warranted. These opinions have been derived in accordance with current standards of pra ctice and no warranty is expressed or implied. Standards of practice are subject to change with time.

PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page 22

7. SELECTED REFERENCES
American Society of Civil Engineers (ASCE), 2013, “ Minimum Design Loads for Buildings and Other Structures,” ASCE/SEI 7-10, Third Printing, Errata Incorporated through March 15.

ASTM, “Soil and Rock: American Society for Testing and Materials,” volumes 4.08 and 4.09.

Bryant, W.A., and Hart, E.W., 2007, "Fault Rupture Ha zard Zones in California, Alquist-Priolo Earthquake Fault Zoning Act with Index to Earthquak e Fault Zones Maps," California Geological Survey: Special Publication 42.

California Code of Regulations, Title 24, 2016 “California Building Code,” 3 volumes.

California Geological Survey (CGS, formerly referred to as the California Division of Mines and Geology), 1977, “Geologic Map of California.”
____, 1998, “Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada,” International Conference of Building Officials.

GeoTek, Inc., In-house proprietary information.

Kennedy, M.P., and Tan, S.S., 1996, “Geologic Map o f the Oceanside, San Luis Rey, and San Marcos 7.5’ Quadrangles, San Diego County, California,” DMG Open-File Report 96-02. ____, 2007, “Geologic Map of the Oceanside 30x60-mi nute Quadrangle, California,” California Geological Survey, Regional Geologic Map No. 2, map scale 1:100,000.

Structural Engineers Association of California/Cali fornia Office of Statewide Health Planning and Development (SEOC/OSHPD), 2019, Seismic Design Maps web interface, accessed May 12, 2019 at https://seismicmaps.org

PN: 3575-SD DATE: April 2019
Pacific Group
APN 220-210-49-00
San Marcos, CA
1384 Poinsettia Avenue, Suite A
Vista, California 92081
Figure 1
Site Location Map
N
Imagery from US Forestry Service, 2019
Not to Scale
Approximate
Site Location
N.A.P.

N.A.P.

Afu
Kmm
Kmm
Kmm T-1
T-2
T-3
T-4
T-5
T-6
T-7
Not to Scale
N.A.P.

N.A.P.

SL-1
SL-2
SL-3
PB-2
Approximate Location of
Percolation Test Boring
PB-2
Not A Part of Site
Location
N.A.P.

T-7 Approximate Limits of
This Report
Approximate Location
of Exporatory Test Pit
Legend
Kmm
Afu
Bedrock, Monzo Granite
Artificial Fill, Not Documented
Approximate Location of Exploratory
Sesmic Refraction Survey
Geologic Contact
PB-1
PN: 3575-SD
Figure 2
Geotechnical Map 1384 Poinsettia Avenue, Suite A
Vista, California 92081 DATE: May 2019
Pacific Group
Northest Corner of
Woodward St. & E. Mission Rd
San Marcos, California
N

APPENDIX A

EXPLORATORY TRENCH LOGS
AND

SEISMIC REFRASCTION EVALUATION REPORT

PACIFIC GROUP Project No. 3575-SD
Preliminary Geotechnical Evaluation May 16, 2019
APN 220-210-49, San Marcos, California Page A-1

A - FIELD TESTING AND SAMPLING PROCEDURES

Bulk Samples (Large)
These samples are normally large bags of earth mate rials over 20 pounds in weight collected from the field by means of hand digging or exploratory cuttings.

B –TRENCH LOG LEGEND
The following abbreviations and symbols often appea r in the classification and description of soil and rock on the logs of borings and trenches:

SOILS
USCS Unified Soil Classification System
f-c Fine to coarse
f-m Fine to medium

GEOLOGIC
B: Attitudes Bedding: strike/dip
J: Attitudes Joint: strike/dip
C: Contact line
……….. Dashed line denotes USCS material change
Solid Line denotes unit / formational change
Thick solid line denotes end of boring
(Additional denotations and symbols are provided on the logs) GeoTek, Inc.

LOG OF EXPLORATORY BORING
BB-1 MD
---Small Bulk ---No Recovery ---W ater Table AL = Atterberg Limits EI = Expansion Index SA = Si eve Analysis RV = R-Value Test SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density 30 LEGEND
Sample type : ---Ring ---SPT ---Large Bulk Lab testing:
25 20

15 10
Practical Refusal
No groundwater encountered
Backfilled with soil cuttings

On N.W. side wall, large boulder, less weathered, jointed Practical Refusal
5 Trench Terminated at 4 Feet
Granitic Bedrock
Weathered granite (poorly graded sand), medium dense, damp, coarse sand, angular small boulders in spoils, light grayish brown and orange brown, oxidized

Water
Content (%)
Dry Density
(pcf)
Others

MATERIAL DESCRIPTION AND COMMENTS

SAMPLES
USCS Symbol
Laboratory Testing
Depth (ft)
Sample Type
Blows/ 6 in
Sample
Number
TRENCH NO.: T-1
ELEVATION: 730' DATE: 4/26/2019
HAMMER: NA RIG TYPE: CAT 420 E PROJECT NO.:

LOCATION:
3575-SD
See Geotechnical Map
Backhoe OPERATOR:

DRILLER: Luna Construction LOGGED BY: CL
DRILL METHOD:

CLIENT:

PROJECT NAME:

Pacific Group
Woodward
GeoTek, Inc.

LOG OF EXPLORATORY BORING
SM
MD, SR
BB-1
---Small Bulk ---No Recovery ---W ater Table AL = Atterberg Limits EI = Expansion Index SA = Si eve Analysis RV = R-Value Test SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density 30 LEGEND
Sample type : ---Ring ---SPT ---Large Bulk Lab testing:
25 20

15 10
No groundwater encountered
Backfilled with soil cuttings

Granitic Bedrock
5 Trench Terminated at 4.5 Feet (Practical Refusal)
Silty sand, loose, dry, orange-brown, fine to medium sand, rootlets, ~ 1/2 dozen fresh granite boulders

Dry Density
(pcf)
Others

Artificial Fill Undocumented

SAMPLES
USCS Symbol
TRENCH NO.: T-2
Laboratory Testing
Depth (ft)
Sample Type
Blows/ 6 in
Sample
Number
Water
Content (%)
LOCATION: See Geotechnical Map ELEVATION: 730' DATE: 4/26/2019 PROJECT NO.: 3575-SD HAMMER: NA RIG TYPE: CAT 420 E
PROJECT NAME: Woodward DRILL METHOD: Backhoe OPERATOR:

CLIENT: Pacific Group DRILLER: Luna Construction LOGGED BY: CL GeoTek, Inc.

LOG OF EXPLORATORY BORING
---Small Bulk ---No Recovery ---W ater Table AL = Atterberg Limits EI = Expansion Index SA = Si eve Analysis RV = R-Value Test SR = Sulfate/Resisitivity Test SH = Shear Test CO = Consolidation test MD = Maximum Density 30 LEGEND
Sample type : ---Ring ---SPT ---Large Bulk Lab testing:
25 20

15 10
Trench Terminated at 5 Feet (Practical Refusal)
No groundwater encountered
Backfilled with soil cuttings
5 Granitic Bedrock
light gray brown to orange brown, oxidized, some areas are weathered to a clayey sand

Dry Density
(pcf)
Others

MATERIAL DESCRIPTION AND COMMENTS
poorly graded coarse sand, dense, damp,
Artificial Fill Undocumented

SAMPLES
USCS Symbol
TRENCH NO.: T-3
Laboratory Testing
Depth (ft)
Sample Type
Blows/ 6 in
Sample
Number
Water
Content (%)
LOCATION: See Geotechnical Map ELEVATION: 730' DATE: 4/26/2019 PROJECT NO.: 3575-SD HAMMER: NA RIG TYPE: CAT 420 E
PROJECT NAME: Woodward DRILL METHOD: Backhoe OPERATOR:

CLIENT: Pacific Group DRILLER: Luna Construction LOGGED BY: CL GeoTek, Inc.

15 10
Trench Terminated at 5 Feet (Practical Refusal)
No groundwater encountered
Backfilled with soil cuttings
5 Granitic Bedrock
Silty sand, loose, moist, light brown to dark brown, fine to medium sand, fill mottling

Dry Density
(pcf)
Others

MATERIAL DESCRIPTION AND COMMENTS
Artificial Fill Undocumented

SAMPLES
USCS Symbol
TRENCH NO.: T-4
Laboratory Testing
Depth (ft)
Sample Type
Blows/ 6 in
Sample
Number
Water
Content (%)
LOCATION: See Geotechnical Map ELEVATION: 730' DATE: 4/26/2019 PROJECT NO.: 3575-SD HAMMER: NA RIG TYPE: CAT 420 E
PROJECT NAME: Woodward DRILL METHOD: Backhoe OPERATOR:

CLIENT: Pacific Group DRILLER: Luna Construction LOGGED BY: CL GeoTek, Inc.

15 10
Backfilled with soil cuttings

Trench Terminated at 3 Feet
5 Practical Refusal
No groundwater encountered
Lightly weathered granite (poorly graded course sand), dense, damp, light grey brown
Practicial Refusal
Dry Density
(pcf)
Others

MATERIAL DESCRIPTION AND COMMENTS
Granitic Bedrock

SAMPLES
USCS Symbol
TRENCH NO.: T-5
Laboratory Testing
Depth (ft)
Sample Type
Blows/ 6 in
Sample
Number
Water
Content (%)
LOCATION: See Geotechnical Map ELEVATION: 730' DATE: 4/26/2019 PROJECT NO.: 3575-SD HAMMER: NA RIG TYPE: CAT 420 E
PROJECT NAME: Woodward DRILL METHOD: Backhoe OPERATOR:

CLIENT: Pacific Group DRILLER: Luna Construction LOGGED BY: CL GeoTek, Inc.

15 10
Backfilled with soil cuttings

Trench Terminated at 3 Feet
5 Practical Refusal
No groundwater encountered
Fresh granite, weathered pockets, poorly graded coarse sand, dense, pockets of oxidation, joints
Practicial refusal
Dry Density
(pcf)
Others

MATERIAL DESCRIPTION AND COMMENTS
Granitic Bedrock

SAMPLES
USCS Symbol
TRENCH NO.: T-6
Laboratory Testing
Depth (ft)
Sample Type
Blows/ 6 in
Sample
Number
Water
Content (%)
LOCATION: See Geotechnical Map ELEVATION: 730' DATE: 4/26/2019 PROJECT NO.: 3575-SD HAMMER: NA RIG TYPE: CAT 420 E
PROJECT NAME: Woodward DRILL METHOD: Backhoe OPERATOR:

CLIENT: Pacific Group DRILLER: Luna Construction LOGGED BY: CL GeoTek, Inc.

15 10
No groundwater encountered
Backfilled with soil cuttings

Practical refusal
Trench Terminated at 3.5 Feet
5 Practical Refusal
Weathered granite, silty sand, orange brown, moist, fine to medium sand, dense Becomes less weathered with depth

Dry Density
(pcf)
Others

MATERIAL DESCRIPTION AND COMMENTS
Granitic Bedrock

SAMPLES
USCS Symbol
TRENCH NO.: T-7
Laboratory Testing
Depth (ft)
Sample Type
Blows/ 6 in
Sample
Number
Water
Content (%)
LOCATION: See Geotechnical Map ELEVATION: 730' DATE: 4/26/2019 PROJECT NO.: 3575-SD HAMMER: NA RIG TYPE: CAT 420 E
PROJECT NAME: Woodward DRILL METHOD: Backhoe OPERATOR:

CLIENT: Pacific Group DRILLER: Luna Construction LOGGED BY: CL Subsurface Surveys & Associates, Inc.
2075 Corte Del Nogal, Suite W Carlsbad, CA 92011
Phone: (760) 476-0492 Fax: (760) 476-0493
GeoTek. Inc. May 1, 2019 1384 Poinsettia Ave, Suite A
Vista, CA 92081
Attn: Chris Livesey Re: Seismic Survey Summary Report
Woodward Project, San Marcos
Subsurface Surveys has completed a seismic refraction survey at the Woodward Project Site, in San Marcos, California. The purpose of the survey was to measure the compressional wave velocity of bedrock for rippability assessment and to provide cross sections showing thickness of the weathered zone and depth to the unweathered interface. This should be useful for planning cuts, grading, and other earthwork.

The field work was conducted on April 26, 2019. Three seismic lines were recorded at locations selected by GeoTek. A survey location map is provided on Figure 1 that shows the position and orientation of the traverses.

GEOLOGIC SETTING
A review of the “Geologic Map of the Oceanside 30'x60' Quadrangle”, (Department of Conservation, 2005) indicates the local area is underlain by tonalite (Kt) of mid-Cretaceous age.

Tonalite is also referred to as quartz diorite. This rock is a member of the Peninsular Ranges Batholith. Surface deposits are mostly loose soil and colluvium.

DATA ACQUISITION AND FIELD METHODS
Seismic refraction data were recorded with a Bison 9024 signal enhancement seismograph and 30 Hz geophones. The standard spread layout used 24 geophones with a 5-foot spacing. Each spread used five shotpoints, one off each end (5-foot offset) and three within the interior of the spread. Depth of investigation was approximately 25-30 feet.

Compressional wave energy was created by sledge hammer impacts on a metal plate. The signal enhancement feature of the seismograph allowed returns from repeated hits to be stacked, thus improving the signal. Vehicle traffic was not a factor during the survey. Each record was stored digitally on an internal hard disk and printed copies of each seismogram were made in the field on thermal paper.

Relative elevations of all shotpoints and geophones were determined by differential leveling with a hand level. Geophone 1 (distance = 0 ft.) at the beginning of each line was assigned a elevation value of 0.0 feet. This datum point served as the reference elevation for all other measurements.

Labeled wooden stakes were placed at the beginning and end of each spread and a Garmin handheld GPS receiver was used to record the latitude and longitude coordinates of the stakes.

The coordinates were used to make the location map shown on Figure 1.

SEISMIC REFRACTION METHOD
The refraction method involves measuring the total time for compressional waves to travel from a shotpoint through the subsurface to a set of geophones placed linearly along the ground. Based on Snell's Law, when two or more layers are present with increasingly higher acoustic velocity, waves become critically refracted across the layer boundaries and begin traveling at the speed of the underlying layer. The advancing waves then generate new wavefronts back to the ground surface. The first surge of energy hitting the geophone is termed the "first arrival" and is depicted on the seismogram as a high angle deflection along each trace.

Recognition of direct wave arrivals (non-refracted) verses refracted waves is a key element of refraction interpretation. To assist this process, the first arrival times measured from the seismic records are plotted on graphs of time verses distance called Time-Distance graphs. An example T-D graph from Line 3 is shown on Figure 2. Based on changes in slope on the graphs, a preliminary layer number (i.e. 1, 2, 3) is assigned to each segment of the graph. The layer assignments together with time, distance and elevation data are input to a computer for additional processing.

DATA REDUCTION AND VELOCITY DETERMINATION
Processing and interpretation of this data set was accomplished with “SIPT2", an interactive inversion modeling program developed by James Scott for the U.S. Bureau of Mines. The inversion algorithm uses the delay time method to construct a first pass depth model. The model is then adjusted by an iterative ray tracing process that attempts to minimize the discrepancies between the total travel times calculated along ray paths and the observed travel times measured in the field.

This program calculates refractor velocity in two ways. First, apparent velocities from each shot are determined by the inverse slope of a best fit (least squares) line through datum-corrected travel times. True velocity is estimated from the apparent velocities by using the following equation:

Vt = 2(Vu x Vd)/(Vu + Vd)
where Vt = true velocity
Vu = apparent up dip velocity
Vd = apparent down dip velocity
2 The second method uses a more sophisticated set of equations (the Hobson-Overton formula) developed by the Canadian Geological Survey. The final velocity assigned to the refractor is a weighted average of the results of the two methods. The weighting is based on the number of arrival times used in the computations.

SUMMARY OF RESULTS
Results from refraction analysis show a three layer solution beneath all lines (see Figures 4-6).

Velocities posted on the cross sections represent averages as described in the previous section.

Therefore, minor localized changes in velocity may occur along any profile. A description of the layers is provided below and a cross section summary is shown in Table 1.

Layer 1 - is mostly loose topsoil and colluvium. Thickness is generally less than 5 feet.

Layer 2 - is interpreted to be weathered bedrock. The velocity range is 3699-3885 ft/sec and is considered rippable with a D-9 Cat.

Layer 3 - represents hard unweathered bedrock.

Table 1. Cross Section Summary Velocity in (ft/sec), Depth in (feet) Velocity Velocity Velocity Depth Range
Line Layer 1 Layer 2 Layer 3 Unweathered Interface 1 1397 3694 8341 8 - 19
2 1365 3669 7764 8 - 13
3 1269 3885 9057 6 - 16
Weathering tends to be gradational for most granitic rock types and usually produces a gradual increase in velocity with depth. Consequently, variation of + 10% from the posted averages may occur between the top and bottom of Layer 2.

Large granitic boulders and core stones in the weathered layer are fairly common in this terrain where chemical and mechanical processes produce spheroidal weathering and exfoliation of the granitic basement rock. The result is remnant large dense spheroids.

Evidence of possible buried core stones were found at this site. Locations are highlighted on Lines 1 and 2 (see Figures 4 and 5).

Figure 4 presents a rippability chart (courtesy of Caterpillar Tractor Co.) for a D9R Ripper. Bar graphs show the relationship between seismic compressional wave velocity and ripper performance for various rock types in three categories: rippable, marginal, and non-rippable.

Granite is listed as marginally rippable at approximately 6700 ft/sec and is considered non- rippable above 8000 ft/sec. This chart is provided only as a guide and should not be considered 3 absolute. Other geologic factors that may influence bedrock rippability at this site include changes in composition of the bedrock and the presence of fractures and joints.

All data acquired during this survey is considered confidential and is available for review by your staff at any time. We appreciate the opportunity to participate in this project.

Please call if there are any questions.
4 Line 1
Line 2
Line 3
0 120 ft.
0 120 ft.
0 120 ft.

Seismic Survey Location Map
Woodward Project Site -- San Marcos, CA
Figure 1
20 (msec)

1.0 0
SP
Geo
* A
0 1. 2 4
20 6
* B
SeisMic Refraction Survey
Geotek Project No. 3575-SD
Example Time-Distance Graph -- Line 3
40 8 1.0 1.2
4/26/201.9
60 * C
80 1.4 1.6
* D

1.8 1.00
20 Woodward Project Site
San Marcos, California
22 1.20 ft
24 * E
20 1.0
0 SP
Geo
Figure 2
Figure 3
Rippers
09A/09T
Ripper Performance
• D9R/D9T
• Multi or Single Shank No. 9 Ripper
• Estimated by Seismic Wave Velocities
Seismic Velocity
Melen; l'8f Second 1000
feel Pet 5ecONI 1000

TOPSOIL
CLAY

GLACIAL TILL

IGNEOUS ROCKS

GRANITE
8ASAlT

TRAP ROCK

SEDIMENTARY ROCKS
SHAI.E

SANDSTONE

SILTSTONE

CLAYSTONE

CONGLOMERATE

BAECCIA
CAllCHE

LIMESTONE

METAMORPHIC ROCKS
so-usr
SLATE
MINERALS and ORES
COl\l

IAONORE
0 2 3

RIPPABLE-
2 3 4
4 5 6 7 8 9 10 11 12 13 14 15
MARGINAL I.__ __ __, NON·RIPPABLE ~'@
20 10
0 Depth (ft)
-10
-20
-30
Line 1

A B C D
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t•:.·•:.·•:.·•:.·•:.·•::•:) soi l (' <' <' <' <' <' <' ) weath. bedrock 100
f.~-t..-t..~ unwea th
120 ft
bedrock
SeisMic Refraction Survey 4/26/2019 Woodward Project Site Geotek Project No. 3575 - SD San Marcos, California Figure 4 20 10
0 Depth (ft)
-10
-20
-30
Line 2
A B C
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t•:.·•:.·•:.·•:.·•:.·•::•:) soil (' <' <' <' <' <' <' ) weath. bedrock 100
f.~-t..-t..~ unwea th
120 ft
bedrock
SeisMic Refraction Survey 4/26/2019 Woodward Project Site Geotek Project No. 3575 - SD San Marcos, California Figure 5 30 20
10 0
Depth (ft)
-10
- 20
Line 3
... ... ::::::::
..... :::::::::::.-: ... :-.-:::.-:::::::::::.-:
. . : : ::.-:-:::-:: ~{: ~{: ~{: ~(: }:: /·::

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0 20 40 60 80 100
t•:.·•:.·•:.·•:.·•:.·•::-:) soil (' <' <' <' <' <' <' ) weath. bedrock f.~-t..-t..~ unwea th 120 ft
bedrock
SeisMic Refraction Survey 4/26/2019 Woodward Project Site Geotek Project No. 3575 - SD San Marcos, California Figure 6 Project: Woodward , Job No.: 3575-SD Test Hole No.: PB-1 Tested By: SE , Date: 5/1/19 .

Depth of Hole As Drilled: 12" Before Test: 12" After Test: 12" .

Reading
No. Time
Time
Interval
(Min)
Total
Depth of
Hole
(Inches)
Initial
Water
Level
(Inches)
Final
Water
Level
(Inches)

∆ In Water
Level
(Inches)
1 10:01 30 12 1.875 5.625 3.75
2 10:31 30 12 4 7.125 3.125
3 11:02 30 12 3.375 6 2.625
4 11:34 30 12 3.375 6.25 2.875
5 12:09 30 12 3.375 6 2.625
6 12:40 30 12 3.375 6.125 2.75
7 13:11 30 12 3.625 6.625 3
8 13:44 30 12 3.375 6.125 2.75
9 14:17 30 12 3.625 6.625 3

PERCOLATION DATA SHEET
Comments
Project: Woodward , Job No.: 3575-SD Test Hole No.: PB-2 Tested By: SE , Date: 5/1/19 .

Depth of Hole As Drilled: 13" Before Test: 13" After Test: 13" Reading
No. Time
Time
Interval
(Min)
Total
Depth of
Hole
(Inches)
Initial
Water
Level
(Inches)
Final
Water
Level
(Inches)

∆ In Water
Level
(Inches)
1 10:10 30 13 7.125 0 7.125
2 10:39 30 13 2.75 6.75 4
3 11:15 30 13 3.75 7.875 4.125
4 11:47 30 13 3.375 6.375 3
5 12:19 30 13 3 6.125 3.125
6 12:50 30 13 3.25 6.25 3
7 13:21 30 13 3.25 6.375 3.125
8 13:54 30 13 3.125 6.125 3
9 14:28 30 13 3 6.25 3.25

PERCOLATION DATA SHEET
Comments
Equation - It =
Havg = (HO+HF)/2 =
It = Inches per Hour
Time Interval, Δt = 30
Client: Pacific Group
Project: Woodward
Project No: 3575-SD
Date: 5/1/2019
Boring No. PB-1
Percolation Rate (Porchet Method)
Final Depth to Water, DF = 6.625
Test Hole Radius, r = 1.8
Initial Depth to Water, D
O = 3.625

0.68 Total Test Hole Depth, DT = 12
ΔH (60r)
Δt (r+2Havg)
HO = DT - DO = 8.38
HF = DT - DF = 5.38
ΔH = ΔD = HO- HF = 3.00

6.88 Equation - It =
Havg = (HO+HF)/2 =
It = Inches per Hour
Time Interval, Δt = 30
Client: Pacific Group
Project: Woodward
Project No: 3575-SD
Date: 5/1/2019
Boring No. PB-2
Percolation Rate (Porchet Method)
Final Depth to Water, DF = 6.625
Test Hole Radius, r = 1.75
Initial Depth to Water, D
O = 3

0.70 Total Test Hole Depth, DT = 13
ΔH (60r)
Δt (r+2Havg)
HO = DT - DO = 10
HF = DT - DF = 6.38
ΔH = ΔD = HO- HF = 3.63

8.19 APPENDIX B

RESULTS OF LABORATORY TESTING

Tested By: SE

COMPACTION TEST REPORT
Dry density, pcf
126
127
128
129
130
131
Water content, %
3 4.5 6 7.5 9 10.5 12

8.7%, 130.2 pcf
Test specification: ASTM D 1557-91 Procedure A Modified 2-4'
Gravel Sand
3575-SD Pacific Group
Elev/ Classification Nat. Sp.G. LL PI % > % <
Depth USCS AASHTO Moist. #4 No.200

TEST RESULTS MATERIAL DESCRIPTION
Project No. Client: Remarks:

Project:

Location: T-1 Sample Number: BB-1
Figure
Maximum dry density = 130.2 pcf
Optimum moisture = 8.7 %
Woodward
Tested By: SE

COMPACTION TEST REPORT
Dry density, pcf
122
124
126
128
130
132
Water content, %
3 4.5 6 7.5 9 10.5 12

8.8%, 128.2 pcf
Test specification: ASTM D 1557-91 Procedure A Modified 3'
Dark Brown Silty Sand
3575-SD Pacific Group
Elev/ Classification Nat. Sp.G. LL PI % > % <
Depth USCS AASHTO Moist. #4 No.200

TEST RESULTS MATERIAL DESCRIPTION
Project No. Client: Remarks:

Project:

Location: T-2 Sample Number: BB-1
Figure
Maximum dry density = 128.2 pcf
Optimum moisture = 8.8 %
Woodward
Project X REPORT S190506A
Corrosion Engineering Page 1
Corrosion Control – Soil, Water, Metallurgy Testing Lab

29990 Technology Dr, Suite 13, Murrieta, CA 92563 Tel: 213-928-7213 Fax: 951-226-1720 www.projectxcorrosion.com
Results Only Soil Testing
for
Woodward

May 6, 2019

Prepared for:

Chris Livesey
Geotek, Inc
1384 Poinsettia Ave, Suite A
Vista, CA, 92081
[email protected]

Project X Job#: S190506A
Client Job or PO#: 3575-SD

Project X REPORT S190506A
Corrosion Engineering Page 2
Corrosion Control – Soil, Water, Metallurgy Testing Lab

29990 Technology Dr, Suite 13, Murrieta, CA 92563 Tel: 213-928-7213 Fax: 951-226-1720 www.projectxcorrosion.com
Soil Analysis Lab Results
Client: Geotek, Inc
Job Name: Woodward
Client Job Number: 3575-SD
Project X Job Number: S190506A
May 6, 2019

Method SM 4500-
NO3-E
SM 4500-
NH3-C
SM 4500-
S2-D
ASTM
G200
ASTM
G51
Bore# /
Description
Depth Nitrate Ammonia Sulfide Redox pH
(ft) (Ohm-cm) (Ohm-cm) (mg/kg) (wt%) (mg/kg) (wt%) (mg/kg) (mg/kg) (mg/kg) (mV) T-2 / BB-1 3.0 482,400 12,730 7.4 0.0007 5 0.0005 9 1.5 0.84 130 8.68 Resistivity
As Rec'd | Minimum
ASTM
D516
ASTM
D512B
ChloridesSulfates
ASTM
G187

Unk = Unknown
NT = Not Tested
ND = 0 = Not Detected
mg/kg = milligrams per kilogram (parts per million) of dry soil weight Chemical Analysis performed on 1:3 Soil-To-Water extract

Please call if you have any questions.

Prepared by,

Nathan Jacob
Lab Technician

Respectfully Submitted,

Eddie Hernandez, M.Sc., P.E.

Sr. Corrosion Consultant
NACE Corrosion Technologist #16592
Professional Engineer
California No. M37102
[email protected]

APPENDIX C

GENERAL EARTHWORK GRADING GUIDELINES

Grading Guidelines ` APPENDIX C

Page 1 ends

GENERAL GRADING GUIDELINES
Guidelines presented herein are intended to address general construction procedures for earthwork construction. Specific situations and conditions often arise which cannot reasonably be discussed in general guidelines, when anticipated these are discussed in the text of the report. Often unanticipated conditions are encountered which may necessitate modification or c hanges to these guidelines. It is our hope that the se will assist the contractor to more efficiently complete the project by providing a reasonable understanding of the procedures that would be expected during earthwork and the testing and observation used to evaluate those procedures.

General
Grading should be performed to at least the minimum requirements of governing agencies, Chapters 18 and 33 of the Uniform Building Code and the guidelines presented below.

Preconstruction Meeting
A preconstruction meeting should be held prior to s ite earthwork. Any questions the contractor has regarding our recommendations, general site conditi ons, apparent discrepancies between reported and actual conditions and/or differences in procedures the contractor intends to use should be brought up at that meeting. The contractor (including the main onsite representative) should review our report and these guidelines in advance of the meeting. Any comments the contractor may have regarding these guidelines should be brought up at that meeting.

Grading Observation and Testing

1. Observation of the fill placement should be provided by our representative during grading. Verbal communication during the course of each day will be used to inform the contractor of test results.

The Contractor should receive a copy of the "Daily Field Report" indicating results of field density tests that day. If our representative does not prov ide the contractor with these reports, our office should be notified.

2. Testing and observation procedures are, by their nature, specific to the work or area observed and location of the tests taken, variability may occur in other locations. The contractor is responsible for the uniformity of the grading operations, our o bservations and test results are intended to evaluate the contractor’s overall level of efforts during grading. The contractor’s personnel are the only individuals participating in all aspect of site work. Compaction testing and observation should not be considered as relieving the contractor’s responsibility to properly compact the fill.

3. Cleanouts, processed ground to receive fill, key excavations, and subdrains should be observed by our representative prior to placing any fill. It w ill be the Contractor's responsibility to notify ou r representative or office when such areas are ready for observation.

4. Density tests may be made on the surface material t o receive fill, as considered warranted by this firm.

5. In general, density tests would be made at maximum intervals of two feet of fill height or every 1,000 cubic yards of fill placed. Criteria will vary depending on soil conditions and size of the fill.

More frequent testing may be performed. In any case , an adequate number of field density tests should be made to evaluate the required compaction and moisture content is generally being obtained.

6. Laboratory testing to support field test procedures will be performed, as considered warranted, based on conditions encountered (e.g. change of material sources, types, etc.) Every effort will be Grading Guidelines ` APPENDIX C

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made to process samples in the laboratory as quickl y as possible and in progress construction projects are our first priority. However, laborator y workloads may cause in delays and some soils may require a minimum of 48 to 72 hours to complete test procedures . Whenever possible, our representative(s) should be informed in advance of operational changes that might result in different source areas for materials.

7. Procedures for testing of fill slopes are as follows:
a) Density tests should be taken periodically during grading on the flat surface of the fill three to five feet horizontally from the face of the slope.
b) If a method other than over building and cutting ba ck to the compacted core is to be employed, slope compaction testing during construct ion should include testing the outer six inches to three feet in the slope face to deter mine if the required compaction is being achieved.

8. Finish grade testing of slopes and pad surfaces should be performed after construction is complete.

Site Clearing

1. All vegetation, and other deleterious materials, should be removed from the site. If material is not immediately removed from the site it should be stoc kpiled in a designated area(s) well outside of all current work areas and delineated with flagging or other means. Site clearing should be performed in advance of any grading in a specific area.

2. Efforts should be made by the contractor to remove all organic or other deleterious material from the fill, as even the most diligent efforts may result in the incorporation of some materials. This is especially important when grading is occurring near the natural grade. All equipment operators should be aware of these efforts. Laborers may be required as root pickers.

3. Nonorganic debris or concrete may be placed in deeper fill areas provided the procedures used are observed and found acceptable by our representative . Typical procedures are similar to those indicated on Plate G-4.

Treatment of Existing Ground

1. Following site clearing, all surficial deposits of alluvium and colluvium as well as weathered or creep effected bedrock, should be removed (see Plat es G-1, G-2 and G-3) unless otherwise specifically indicated in the text of this report.

2. In some cases, removal may be recommended to a spec ified depth (e.g. flat sites where partial alluvial removals may be sufficient) the contractor should not exceed these depths unless directed otherwise by our representative.

3. Groundwater existing in alluvial areas may make exc avation difficult. Deeper removals than indicated in the text of the report may be necessary due to saturation during winter months.

4. Subsequent to removals, the natural ground should be processed to a depth of six inches, moistened to near optimum moisture conditions and compacted to fill standards.

5. Exploratory back hoe or dozer trenches still remaining after site removal should be excavated and filled with compacted fill if they can be located.

Subdrainage

1. Subdrainage systems should be provided in canyon bottoms prior to placing fill, and behind buttress and stabilization fills and in other areas indicate d in the report. Subdrains should conform to schematic diagrams G-1 and G-5, and be acceptable to our representative.

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2. For canyon subdrains, runs less than 500 feet may u se six-inch pipe. Typically, runs in excess of 500 feet should have the lower end as eight-inch minimum.

3. Filter material should be clean, 1/2 to 1-inch grav el wrapped in a suitable filter fabric. Class 2 permeable filter material per California Department of Transportation Standards tested by this office to verify its suitability, may be used without filter fabric. A sample of the material should be provided to the Soils Engineer by the contractor at least two working days before it is delivered to the site. The filter should be clean with a wide range of sizes.

4. Approximate delineation of anticipated subdrain locations may be offered at 40-scale plan review stage. During grading, this office would evaluate the necessity of placing additional drains.

5. All subdrainage systems should be observed by our representative during construction and prior to covering with compacted fill.

6. Subdrains should outlet into storm drains where possible. Outlets should be located and protected.

The need for backflow preventers should be assessed during construction.

7. Consideration should be given to having subdrains located by the project surveyors.

Fill Placement

1. Unless otherwise indicated, all site soil and bedro ck may be reused for compacted fill; however, some special processing or handling may be required (see text of report).

2. Material used in the compacting process should be evenly spread, moisture conditioned, processed, and compacted in thin lifts six (6) to eight (8) inches in compacted thickness to obtain a uniformly dense layer. The fill should be placed and compacted on a nearly horizontal plane, unless otherwise found acceptable by our representative.

3. If the moisture content or relative density varies from that recommended by this firm , the Contractor should rework the fill until it is in accordance with the following:
a) Moisture content of the fill should be at or above optimum moisture. Moisture should be evenly distributed without wet and dry pockets. Pr e-watering of cut or removal areas should be considered in addition to watering during fill placement, particularly in clay or dry surficial soils. The ability of the contractor to obtain the proper moisture content will control production rates.
b) Each six-inch layer should be compacted to at least 90 percent of the maximum dry density in compliance with the testing method specified by the controlling governmental agency.

In most cases, the testing method is ASTM Test Designation D-1557.

4. Rock fragments less than eight inches in diameter may be utilized in the fill, provided:
a) They are not placed in concentrated pockets;
b) There is a sufficient percentage of fine-grained material to surround the rocks; c) The distribution of the rocks is observed by and acceptable to our representative.

5. Rocks exceeding eight (8) inches in diameter should be taken off site, broken into smaller fragments, or placed in accordance with recommendations of this firm in areas designated suitable for rock disposal (See Plate G-4). On projects wher e significant large quantities of oversized materials are anticipated, alternate guidelines for placement may be included. If significant oversize materials are encountered during construction, these guidelines should be requested.

6. In clay soil dry or large chunks or blocks are comm on; if in excess of eight (8) inches minimum dimension then they are considered as oversized. Sheepsfoot compactors or other suitable methods should be used to break up blocks. When dry they sh ould be moisture conditioned to provide a uniform condition with the surrounding fill.

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Slope Construction

1. The Contractor should obtain a minimum relative com paction of 90 percent out to the finished slope face of fill slopes. This may be achieved by either overbuilding the slope and cutting back to the compacted core, or by direct compaction of the slope face with suitable equipment.

2. Slopes trimmed to the compacted core should be overbuilt by at least three (3) feet with compaction efforts out to the edge of the false slope. Failure to properly compact the outer edge results in trimming not exposing the compacted core and additi onal compaction after trimming may be necessary.

3. If fill slopes are built "at grade" using direct compaction methods then the slope construction should be performed so that a constant gradient is maintained throughout construction. Soil should not be "spilled" over the slope face nor should slopes be "pushed out" to obtain grades. Compaction equipment should compact each lift along the immediate top of slope. Slopes should be back rolled or otherwise compacted at approximately every 4 feet vertically as the slope is built.

4. Corners and bends in slopes should have special attention during construction as these are the most difficult areas to obtain proper compaction.

5. Cut slopes should be cut to the finished surface, excessive undercutting and smoothing of the face with fill may necessitate stabilization.

Keyways, Buttress and Stabilization Fills
Keyways are needed to provide support for fill slope and various corrective procedures.

1. Side-hill fills should have an equipment-width key at their toe excavated through all surficial soil and into competent material and tilted back into th e hill (Plates G-2, G-3). As the fill is elevated, it should be benched through surficial soil and slo pewash, and into competent bedrock or other material deemed suitable by our representatives (See Plates G-1, G-2, and G-3).

2. Fill over cut slopes should be constructed in the following manner:
a) All surficial soils and weathered rock materials should be removed at the cut-fill interface.
b) A key at least one (1) equipment width wide (or as needed for compaction) and tipped at least one (1) foot into slope should be excavated into competent materials and observed by our representative.
c) The cut portion of the slope should be excavated prior to fill placement to evaluate if stabilization is necessary, the contractor should be responsible for any additional earthwork created by placing fill prior to cut excavation. (See Plate G-3 for schematic details.)

3. Daylight cut lots above descending natural slopes m ay require removal and replacement of the outer portion of the lot. A schematic diagram for this condition is presented on Plate G-2.

4. A basal key is needed for fill slopes extending ove r natural slopes. A schematic diagram for this condition is presented on Plate G-2.

5. All fill slopes should be provided with a key unles s within the body of a larger overall fill mass.

Please refer to Plate G-3, for specific guidelines.

Anticipated buttress and stabilization fills are discussed in the text of the report. The need to stabilize other proposed cut slopes will be evaluated during constr uction. Plate G-5 is shows a schematic of buttress construction.

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1. All backcuts should be excavated at gradients of 1: 1 or flatter. The backcut configuration should be determined based on the design, exposed conditions and need to maintain a minimum fill width and provide working room for the equipment.

2. On longer slopes backcuts and keyways should be excavated in maximum 250 feet long segment.

The specific configurations will be determined during construction.

3. All keys should be a minimum of two (2) feet deep at the toe and slope toward the heel at least one foot or two (2%) percent whichever is greater.

4. Subdrains are to be placed for all stabilization slopes exceeding 10 feet in height. Lower slopes are subject to review. Drains may be required. Guidelines for subdrains are presented on Plate G-5.

5. Benching of backcuts during fill placement is required.

Lot Capping

1. When practical, the upper three (3) feet of material placed below finish grade should be comprised of the least expansive material available. Preferab ly, highly and very highly expansive materials should not be used. We will attempt to offer advis e based on visual evaluations of the materials during grading, but it must be realized that labora tory testing is needed to evaluate the expansive potential of soil. Minimally, this testing takes two (2) to four (4) days to complete.

2. Transition lots (cut and fill) both per plan and th ose created by remedial grading (e.g. lots above stabilization fills, along daylight lines, above natural slope, etc.) should be capped with a three foot thick compacted fill blanket.

3. Cut pads should be observed by our representative(s ) to evaluate the need for overexcavation and replacement with fill. This may be necessary to re duce water infiltration into highly fractured bedrock or other permeable zones, and/or due to differing expansive potential of materials beneath a structure. The overexcavation should be at least three feet. Deeper overexcavation may be recommended in some cases.

ROCK PLACEMENT AND ROCK FILL GUIDELINES

It is anticipated that large quantities of oversize material would be generated during grading. It’s likely that such materials may require special handling for burial. Although alternatives may be developed in the field, the following methods of rock disposal are recommended on a preliminary basis.

Limited Larger Rock
When materials encountered are principally soil with limited quantities of larger rock fragments or boulders, placement in windrows is recommended. The following procedures should be applied:

1. Oversize rock (greater than 8 inch) should be placed in windrows. a) Windrows are rows of single file rocks placed to avoid nesting or clusters of rock. b) Each adjacent rock should be approximately the same size (within ~one foot in diameter). c) The maximum rock size allowed in windrows is four feet

2. A minimum vertical distance of three feet between lifts should be maintained. Also, the windrows should be offset from lift to lift. Rock windrows should not be closer than 15 feet to the face of fill slopes and sufficient space must be maintained for proper slope construction (see Plate G-4).

3. Rocks greater than eight inches in diameter should not be placed within seven feet of the finished subgrade for a roadway or pads and should be held below the depth of the lowest utility. This will allow easier trenching for utility lines.

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4. Rocks greater than four feet in diameter should be broken down, if possible, or they may be placed in a dozer trench. Each trench should be excavated into the compacted fill a minimum of one foot deeper than the largest diameter of rock.
a) The rock should be placed in the trench and granula r fill materials (SE>30) should be flooded into the trench to fill voids around the rock.
b) The over size rock trenches should be no closer together than 15 feet from any slope face. c) Trenches at higher elevation should be staggered an d there should be a minimum of four feet of compacted fill between the top of the one trench and the bottom of the next higher trench.
d) It would be necessary to verify 90 percent relative compaction in these pits. A 24 to 72 hour delay to allow for water dissipation should be anticipated prior to additional fill placement.

Structural Rock Fills
If the materials generated for placement in structural fills contains a significant percentage of material more than six (6) inch in one dimension, then placement using conventional soil fill methods with isolated windrows would not be feasible. In such cases the following could be considered.

1. Mixes of large of rock or boulders may be placed as rock fill. They should be below the depth of all utilities both on pads and in roadways and belo w any proposed swimming pools or other excavations. If these fills are placed within seven (7) feet of finished grade they may effect foundation design.

2. Rock fills are required to be placed in horizontal layers that should not exceed two feet in thickness, or the maximum rock size present, which ever is less . All rocks exceeding two feet should be broken down to a smaller size, windrowed (see above), or disposed of in non-structural fill areas. Localized larger rock up to 3 feet in l argest dimension may be placed in rock fill as follows:
a) individual rocks are placed in a given lift so as to be roughly 50% exposed above the typical surface of the fill ,
b) loaded rock trucks or alternate compactors are work ed around the rock on all sides to the satisfaction of the soil engineer,
c) the portion of the rock above grade is covered with a second lift.

3. Material placed in each lift should be well graded. No unfilled spaces (voids) should be permitted in the rock fill.

Compaction procedures:

Compaction of rock fills is largely procedural. The following procedures have been found to generally produce satisfactory compaction.

1. Provisions for routing of construction traffic over the fill should be implemented. a) Placement should be by rock trucks crossing the lift being placed and dumping at its edge. b) The trucks should be routed so that each pass across the fill is via a different path and that all areas are uniformly traversed.
c) The dumped piles should be knocked down and spread by a large dozer (D-8 or larger suggested). (Water should be applied before and during spreading.)

2. Rock fill should be generously watered (sluiced)
a) Water should be applied by water trucks to the:
i) dump piles,
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ii) front face of the lift being placed and,
iii) surface of the fill prior to compaction.
b) No material should be placed without adequate water. c) The number of water trucks and water supply should be sufficient to provide constant water.
d) Rock fill placement should be suspended when water trucks are unavailable:
i) for more than 5 minutes straight, or,
ii) for more than 10 minutes/hour.

3. In addition to the truck pattern and at the discret ion of the soil engineer, large, rubber tired compactors may be required.
a) The need for this equipment will depend largely on the ability of the operators to provide complete and uniform coverage by wheel rolling with the trucks. b) Other large compactors will also be considered by the soil engineer provided that required compaction is achieved.

4. Placement and compaction of the rock fill is largely procedural. Observation by trenching should be made to check:
a) the general segregation of rock size,
b) for any unfilled spaces between the large blocks, and c) the matrix compaction and moisture content.

5. Test fills may be required to evaluate relative com paction of finer grained zones or as deemed appropriate by the soil engineer.
a) A lift should be constructed by the methods proposed as proposed

6. Frequency of the test trenching is to be at the discretion of the soil engineer.

Control areas may be used to evaluate the contractors procedures.

7. A minimum horizontal distance of 15 feet should be maintained from the face of the rock fill and any finish slope face. At least the outer 15 feet should be built of conventional fill materials.

Piping Potential and Filter Blankets:

Where conventional fill is placed over rock fill, t he potential for piping (migration) of the fine gra ined material from the conventional fill into rock fills will need to be addressed.

The potential for particle migration is related to the grain size comparisons of the materials present and in contact with each other. Provided that 15 percent o f the finer soil is larger than the effective pore size of the coarse soil, then particle migration is substan tially mitigated. This can be accomplished with a w ell- graded matrix material for the rock fill and a zone of fill similar to the matrix above it. The specific gradation of the fill materials placed during grading must be known to evaluate the need for any type of filter that may be necessary to cap the rock fills. This, unfor tunately, can only be accurately determined during construction.

In the event that poorly graded matrix is used in t he rock fills, properly graded filter blankets 2 to 3 feet thick separating rock fills and conventional fill may be needed. As an alternative, use of two layers of filter fabric (Mirafi 700 x or equivalent) could be employ ed on top of the rock fill. In order to mitigate ex cess puncturing, the surface of the rock fill should be well broken down and smoothed prior to placing the filter fabric. The first layer of the fabric may then be p laced and covered with relatively permeable fill material (with respect to overlying material) 1 to 2 feet thick. The relative permeable material should be compacted to fill standards. The second layer of fabric should be placed and conventional fill placement continued.

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Subdrainage
Rock fill areas should be tied to a subdrainage system. If conventional fill is placed that separates the rock from the main canyon subdrain then a secondary syst em should be installed. A system consisting of an adequately graded base (3 to 4 percent to the lower side) with a collector system and outlets may suffice.

Additionally, at approximately every 25 foot vertic al interval, a collector system with outlets should be placed at the interface of the rock fill and the conventional fill blanketing a fill slope Monitoring
Depending upon the depth of the rock fill and other factors, monitoring for settlement of the fill areas may be needed following completion of grading. Typically, if rock fill depths exceed 40 feet, monitoring would be recommend prior to construction of any settlement sensitive improvements. Delays of 3 to 6 months or longer can be expected prior to the start of construction.

UTILITY TRENCH CONSTRUCTION AND BACKFILL

Utility trench excavation and backfill is the contractors responsibility. The geotechnical consultant typically provides periodic observation and testing of these operations. While, efforts are made to make suffici ent observations and tests to verify that the contractors’ methods and procedures are adequate to achieve proper compaction, it is typically impractical to observe all backfill procedures. As such, it is critical th at the contractor use consistent backfill procedures.

Compaction methods vary for trench compaction and experience indicates many methods can be successful.

However, procedures that “worked” on previous proje cts may or may not prove effective on a given site.

The contractor(s) should outline the procedures pro posed, so that we may discuss them prior to construction. We will offer comments based on our knowledge of site conditions and experience.

1. Utility trench backfill in slopes, structural areas , in streets and beneath flat work or hardscape should be brought to at least optimum moisture and compacted to at least 90 percent of the laboratory standard. Soil should be moisture conditioned prior to placing the trench.

2. Flooding and jetting are not typically recommended or acceptable for native soils. Flooding or jetting may be used with select sand having a Sand Equivalent (SE) of 30 or higher. This is typically limited to the following uses:
a) shallow (12 + inches) under slab interior trenches and, b) as bedding in pipe zone.

The water should be allowed to dissipate prior to pouring slabs or completing trench compaction.

3. Care should be taken not to place soils at high moi sture content within the upper three feet of the trench backfill in street areas, as overly wet soils may impact subgrade preparation. Moisture may be reduced to 2% below optimum moisture in areas to be paved within the upper three feet below sub grade.

4. Sand backfill should not be allowed in exterior tre nches adjacent to and within an area extending below a 1:1 projection from the outside bottom edge of a footing, unless it is similar to the surrounding soil.

5. Trench compaction testing is generally at the discr etion of the geotechnical consultant. Testing frequency will be based on trench depth and the con tractors procedures. A probing rod would be used to assess the consistency of compaction between tested areas and untested areas. If zones are found that are considered less compact than other a reas, this would be brought to the contractors attention.

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JOB SAFETY
General
Personnel safety is a primary concern on all job sites. The following summaries our safety considerations for use by all our employees on multi-employer construction sites. On ground personnel are at highest risk of injury and possible fatality on grading construction projects. The company recognizes that construction activities will vary on each site and that job site safety is the contractor's responsibility. Howeve r, it is, imperative that all personnel be safety conscious to avoid accidents and potential injury.

In an effort to minimize risks associated with geot echnical testing and observation, the following precautions are to be implemented for the safety of our field personnel on grading and construction projects.

1. Safety Meetings: Our field personnel are directed t o attend the contractor's regularly scheduled safety meetings.

2. Safety Vests: Safety vests are provided for and are to be worn by our personnel while on the job site.

3. Safety Flags: Safety flags are provided to our fiel d technicians; one is to be affixed to the vehicle when on site, the other is to be placed atop the spoil pile on all test pits.

In the event that the contractor's representative observes any of our personnel not following the above, we request that it be brought to the attention of our office.

Test Pits Location, Orientation and Clearance
The technician is responsible for selecting test pit locations. The primary concern is the technician's safety.

However, it is necessary to take sufficient tests a t various locations to obtain a representative samp ling of the fill. As such, efforts will be made to coordin ate locations with the grading contractors authoriz ed representatives (e.g. dump man, operator, supervisor, grade checker, etc.), and to select locations following or behind the established traffic pattern, preferab le outside of current traffic. The contractors aut horized representative should direct excavation of the pit and safety during the test period. Again, safety i s the paramount concern.

Test pits should be excavated so that the spoil pile is placed away from oncoming traffic. The technician's vehicle is to be placed next to the test pit, opposite the spoil pile. This necessitates that the fill be maintained in a drivable condition. Alternatively, the contractor may opt to park a piece of equipment in front of test pits, particularly in small fill areas or those with limited access.

A zone of non-encroachment should be established fo r all test pits (see diagram below) No grading equipment should enter this zone during the test pr ocedure. The zone should extend outward to the sid es approximately 50 feet from the center of the test pit and 100 feet in the direction of traffic flow. This zone is established both for safety and to avoid excessive ground vibration, which typically decreases test results.

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50 ft Zone of
Non-Encroachment
50 ft Zone of
Non-Encroachment
Traffic Direction
Vehicle
parked here Test Pit Spoil
pile
Spoil
pile
Test Pit

SIDE VIEW

PLAN VIEW

TEST PIT SAFETY PLAN
10 0 ft Zone of
Non-Encroachment

Slope Tests
When taking slope tests, the technician should park their vehicle directly above or below the test loc ation on the slope. The contractor's representative shoul d effectively keep all equipment at a safe operatio n distance (e.g. 50 feet) away from the slope during testing.

The technician is directed to withdraw from the act ive portion of the fill as soon as possible followi ng testing. The technician's vehicle should be parked at the perimeter of the fill in a highly visible location.

Trench Safety:

It is the contractor's responsibility to provide safe access into trenches where compaction testing is needed.

Trenches for all utilities should be excavated in a ccordance with CAL-OSHA and any other applicable safety standards. Safe conditions will be required to enable compaction testing of the trench backfill.

All utility trench excavations in excess of 5 feet deep, which a person enters, are to be shored or laid back.

Trench access should be provided in accordance with OSHA standards. Our personnel are directed not to enter any trench by being lowered or "riding down" on the equipment.

Our personnel are directed not to enter any excavation which;

1. is 5 feet or deeper unless shored or laid back,

2. exit points or ladders are not provide,

3. displays any evidence of instability, has any loose rock or other debris which could fall into the trench, or

4. displays any other evidence of any unsafe conditions regardless of depth.

If the contractor fails to provide safe access to trenches for compaction testing, our company policy requires that the soil technician withdraws and notifies their supervisor. The contractors representative will then be contacted in an effort to effect a solution. All backfill not tested due to safety concerns or other reasons is subject to reprocessing and/or removal.

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Procedures
In the event that the technician's safety is jeopardized or compromised as a result of the contractor's failure to comply with any of the above, the technician is directed to inform both the developer's and contractor's representatives. If the condition is not rectified, the technician is required, by company policy, to immediately withdraw and notify their supervisor. The contractor’s representative will then be contacted in an effort to effect a solution. No further testing will be performed until the situation is rectified . Any fill placed in the interim can be considered unacceptable and subject to reprocessing, recompaction or removal.

In the event that the soil technician does not comply with the above or other established safety guidelines, we request that the contractor bring this to techni cians attention and notify our project manager or o ffice.

Effective communication and coordination between th e contractors' representative and the field technician(s) is strongly encouraged in order to implement the above safety program and safety in general.

The safety procedures outlined above should be disc ussed at the contractor's safety meetings. This wi ll serve to inform and remind equipment operators of t hese safety procedures particularly the zone of non - encroachment.

TYPICAL CANYON

CLEANOUT

STANDARD GRADING

GUIDELINES

ALTERNATES
Original Ground
3’
Loose Surface Materials
PLATE G-1
Finish Grade
3’
Suitable
Material
Suitable
Material
6” Perforated Pipe in 9 cubic feet per Lineal
Foot Clean Gravel Wrapped in Filter Fabric
Construct Benches
where slope exceeds 5:1
Bottom of Cleanout to Be At
Least 1.5 Times the Width of
Compaction Equipment
4 feet typical
Slope to Drain
Original Ground
Loose Surface Materials
Finish Grade
Suitable
MaterialConstruct Benches
where slope exceeds 5:1
Bottom of Cleanout to Be At
Least 1.5 Times the Width of
Compaction Equipment
4 feet typical
Slope to Drain
6” Perforated Pipe in 9 cubic feet
per Lineal Foot Clean Gravel
Wrapped in Filter Fabric

TREATMENT ABOVE

NATURAL SLOPES

STANDARD GRADING

GUIDELINES

TYPICAL FILL SLOPE OVER

NATURAL DESCENDING SLOPE
Topsoil
Bedrock
PLATE G-2
Finish Grade
Fill Slope
Daylight Cut
Line per Plan
Project Removal
at 1 to 1
Min. 3 Feet
Compacted Fill
Colluvium
Creep Zone
Minimum 15 Feet Wide
or 1.5 Equipment
Widths for Compaction
Toe of Fill Slope
per Plan

DAYLIGHT CUT AREA OVER

NATURAL DESCENDING SLOPE
Topsoil
Structural Setback
Without Corrective Work
Project Removal
at 1 to 1
Colluvium
Creep Zone
Min.
2 Feet
Minimum 15 Feet Wide
or 1.5 Equipment
Widths for Compaction
Finish Grade
Bedrock
Min. 3 Feet
Compacted Fill
Min.
2 Feet
Compacted Fill
Compacted Fill
1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505
Topsoil
Colluvium
Creep Zone

COMMON FILL

SLOPE KEYS

STANDARD GRADING

GUIDELINES

TYPICAL FILL SLOPE OVER

CUT SLOPE
Topsoil
Bedrock
PLATE G-3
Finish Grade
2: 1 Fill Slope
4’ Typical
Colluvium
Creep Zone
Minimum 15 Feet Wide
or 1.5 Equipment
Widths for Compaction
Toe of Fill Slope
per Plan

TYPICAL FILL SLOPE
Bedrock or
Suitable Dense Material
Minimum compacted fill required
to provide lateral support.

Excavate key if width or depth
less than indicated in table above
Cut Slope
SLOPE
HEIGHT
MIN. KEY
WIDTH
MIN. KEY
DEPTH
5 10
15 20
25 >25
7 10
15 15
15 SEE TEXT
1 1.5
2 2.5
3 CONTRACTOR TO VERIFY

WITH SOIL ENGINEER

PRIOR TO CONSTRUCTION
1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505

NOTES:
1) SOIL FILL OVER WINDROW SHOULE BE 7 FEET OR PER JURISDUICTIONAL STANDARDS AND SUFFICIENT

FOR FUTURE EXCAVATIONS TO AVOID ROCKS
2) MAXIMUM ROCK SIZE IN WINDROWS IS 4 FEET MINIMUM DIAMETER 3) SOIL AROUND WINDROWS TO BE SANDY MATERIAL SUBJECT TO SOIL ENGINEER ACCEPTANCE 4) SPACING AND CLEARANCES MUST BE SUFFICIENT TO ALLOW FOR PROPER COMPACTION 5) INDIVDUAL LARGE ROCKS MAY BE BURIED IN PITS.

ROCK BURIAL

DETAILS

STANDARD GRADING

GUIDELINES
PLATE G-4
SEE NOTE 1
15’
MIN.
3’ MIN.
3’ MIN.

MINIMUM 15’ CLEAR OR

1.5 EQUIPMENT WIDTHS

FOR COMPACTION

STAGGER ROWS

HORIZONTALLY

NO ROCKS IN

THIS ZONE

CROSS SECTIONAL VIEW

FINISH GRADE

FILL SLOPE

PLAN VIEW

FILL SLOPE
MINIMUM 15’ CLEAR OR 1.5 EQUIPMENT

WIDTHS FOR COMPACTION
MINIMUM 15’ CLEAR OR 1.5 EQUIPMENT

WIDTHS FOR COMPACTION

PLACE ROCKS END TO END

DO NOT PILE OR STACK ROCKS

SOIL TO BE PLACE AROUND AND OVER ROCKS THEN FLOODED INTO VOIDS. MUST COMPACT AROUND AND OVER EACH ROCK WINDROW
1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505

6” Perforated Pipe in 6 cubic
feet per lineal foot clean gravel
wrapped in filter fabric outlet
pipe to gravity flow

BEDROCK COMPACTED FILL
MIN. 3 FEET

COMPACTED FILL

TERRACE DRAIN

AS REQUIRED
2 1
MIN. 15 FEET WIDE OR 1.5 EQUIPMENT

WIDTHS FOR COMPACTION
MIN. 2 FEET

EMBEDDMENT
1384 Poinsettia Avenue, Suite A
Vista, California 92083
Typical Buttress and
Stabilization Fill PLATE G-5
4” or 6” Perforated Pipe in 6 cubic
feet per lineal foot clean gravel
wrapped in filter fabric outlet pipe
to gravity flow at 2% min.

TRANSITION &
UNDERCUT LOTS PLATE G-6

TRANSITION LOT

PROPSED FINISH GRADE

COMPETENT MATERIAL
4’ MIN.

OVEREXCAVATE AND

RECOMPACT

PROPOSED STRUCTURE

COMPACTED FILL
3 1

OVEREXCAVATION AND BENCHING NOT
TO EXCEED INCLINATION OF 3:1 (H:V)

UNDERCUT LOT

PROPSED FINISH GRADE

PROPOSED STRUCTURE
4’ MIN.

COMPETENT MATERIAL

COMPACTED FILL

OVEREXCAVATE AND

RECOMPACT
OVEREXCAVATION TO HAVE 1%

FALL TOWARD FRONT OF LOT
Notes:

1. Removed/overexcavated soils should be recompacted in accordance with recommendations included in the text of the report.

2. Location of cut/fill transition should verified in the field during site grading.

STANDARD GRADING
GUIDELINES1384 Poinsettia Avenue, Suite A
Vista, California 92081-8505

San Marcos City CouncilSeptember 9, 2025

San Marcos City Council
September 9, 2025