Sand Equivalent: Four samples were selected for sand equivalent testing in accordance with ASTM D2419. This test is useful in detecting variations in grain size distribution, backfill suitability and pavement subgrade support. The results of this testing are shown below.
Location Depth (ft) Sand Equivalent
TR-01 0 – 4 3
S-1 0 – 1 11
S-2 0 – 1 13
S-3 0 – 1 12
R-value: One sample was selected for R-value testing. This test measures the ability of soil to resist lateral deformation under applied vertical loads, and is used in developing parameters for pavement structural section design. Testing was performed in accordance with ASTM D2844.
Location Depth (ft) R-value
S-1 0 – 1 26
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Packet Pg. 489 Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06- __________________________________
Geotechnical Invest. – Esplanade Avenue
Project No. S026-180 – May 2019 B-2 Inland Foundation Engineering, Inc.
GENERAL
All laboratory testing has been conducted in conformance with the applicable ASTM test methods by personnel trained and supervised in conformance with our QA/QC policy.
Our test data only relates to the specific soils tested. Soil conditions typically vary and any significant variations should be reported to our laboratory for review and possible testing. The data presented in this report are for the use of the City of San Jacinto only and may not be reproduced or used by others without written approval of Inland Foundation Engineering, Inc.
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Packet Pg. 490 Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06- 100
105
110
115
120
125
130
135
140
145
150
0 10 20 30 40 50
BOREHOLE DEPTH
120.1 PCF 11.9 %
Max DD Optimum WC
TR-01
Description of Materials
0.0 SANDY CLAY (CL)
DRY DENSITY, pcf
WATER CONTENT, %
MOISTURE-DENSITY CURVES (ASTM D1557)
FIGURE NO. B-3
PROJECT NUMBER S026-180
CLIENT City of San Jacinto PROJECT NAME Geotechnical Investigation PROJECT LOCATION Esplanade Avenue Widening
. San Jacinto
IFE COMPACTION - GINT STD US LAB.GDT - 5/20/19 17:28 - P:\S026\S026-180 ESPLANADE ROAD WIDENING\CITY OF SAN JACINTO ESPLANADE, WARREN TO SANDERSON\GINT.GPJ Inland Foundation Engineering, Inc.
Curves of 100% Saturation
for Specific Gravity Equal to:
2.80 2.70
2.60 4.1.c
Packet Pg. 491 Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06- 0 5
10 15
20 25
30 35
40 45
50 55
60 65
70 75
80 85
90 95
100
0.0010.010.1110100
PI Cc CuLL PL
COBBLES GRAVEL
40.2 35.8
37.8 64.0
12.5 19
12.5 25
SAND
GRAIN SIZE IN MILLIMETERS
coarse fine
CLAYEY SAND (SC)
SILTY, CLAYEY SAND (SC-SM)
SILTY, CLAYEY SAND (SC-SM)
SANDY CLAY (CL)
Classification
1/2 50
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS HYDROMETER 6 3 1.5 8 143/4 3/8 4 20 40 60 140
0.0 0.0
0.0 0.0
PERCENT FINER BY WEIGHT
GRADATION CURVES (ASTM D422, ASTM D4318)
FIGURE NO. B-4
D100 D60 D30 D10 %Gravel
0.145
0.152
0.136
1 2
3 TR-01
coarse SILT OR CLAYfinemedium
0.0 0.0
0.0 0.0
%Sand %Silt %Clay
3.6 5.1
1.6 4.7
56.2 59.1
60.6 31.3
BOREHOLE DEPTH
BOREHOLE DEPTH
3 100
1 2
3 TR-01
24 16 30
1 6 10 200
PROJECT NUMBER S026-180
CLIENT City of San Jacinto PROJECT NAME Geotechnical Investigation PROJECT LOCATION Esplanade Avenue Widening
. San Jacinto
IFE SIEVE ANALYSIS - GINT STD US LAB.GDT - 5/20/19 17:29 - P:\S026\S026-180 ESPLANADE ROAD WIDENING\CITY OF SAN JACINTO ESPLANADE, WARREN TO SANDERSON\GINT.GPJ Inland Foundation Engineering, Inc.
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Packet Pg. 492 Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06- IFE Inland Foundation Engineering, Inc.
inlandfoundation.com
1310 South Santa Fe Ave. PO Box 937 San Jacinto, CA 92581 ꓲ (951) 654-1555 77622 Country Club Dr. Suite Q, Palm Desert, CA 92211 ꓲ (760) 200-2400 February 12, 2026
Project No. S026-180
City of San Jacinto
c/o Interwest
1221 S. San Jacinto Avenue
San Jacinto, CA 92583
Attention: Stuart E. McKibbin, PE
Contract City Engineer
Subject: Geotechnical Investigation Report Addendum
Revised Subgrade Preparation Recommendations
Esplanade Avenue Widening – Warren Road to Sanderson Avenue San Jacinto, California
References: Geotechnical Investigation, City of San Jacinto, Esplanade Avenue Widening Project, Warren Road to Sanderson Avenue, North Side, prepared by Inland Foundation Engineering, Inc., dated May 30, 2019, revised August 15, 2019, Project No. S026-180
Plans for City of San Jacinto, California, Esplanade Avenue Widening Phase 1, Warren Road to Sanderson Avenue, CIP #06-145 (SJ-222), Sheets 27 of 27, prepared by Interwest Consulting Group, dated January 21, 2026 (Addendum 1), File No. SJ-222_Design
Dear Mr. McKibben:
This report addendum has been prepared to provide supplemental subgrade preparation recommendations for the subject project. Since preparation of the referenced geotechnical investigation report, Eastern Municipal Water District (EMWD) has completed construction of their San Jacinto Valley Raw Water Conveyance Facilities Project, which included placement of a 60-inch CML&C pipeline north of the existing Esplanade Avenue pavement from Warren Road to Sanderson Avenue. The pipeline is within the limits of the proposed widening project. The pipeline was constructed in an approximately 7-ft wide shored trench that provided 1 foot of clearance on each side of the pipe. The trench backfill was compacted to 90 percent relative compaction to ground surface.
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Packet Pg. 493 Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06- ____________________________________________________
Report Addendum – Esplanade Avenue Widening
Project No. S026-180, February 2026 2 of 2 Inland Foundation Engineering, Inc.
The referenced geotechnical investigation report includes the recommendation that existing soil within the limits of the proposed construction be removed to a depth of at least 36 inches below existing grades, or to a depth of at least 24 inches below proposed pavement subgrade, whichever is deeper. Information provided by the City shows that the depth to top of pipe is as close as 5.5 feet to finish grade elevation, which is less than 4 feet to the design subgrade elevation. Considering the backfill placement and grading performed by EMWD along the north side of Esplanade Avenue, the subgrade preparation recommendations should be revised as follows.
Subgrade Preparation. Soil in the area to be widened along the north side of the existing pavement should be removed to a depth of at least 24 inches below pavement subgrade, or as otherwise directed by the Engineer. Within 3 feet of centerline of the EMWD pipe, the existing soil is considered suitable for pavement support and need not be removed. In areas where the existing pavement is to be replaced, the existing asphalt concrete and aggregate base should be removed to the design subgrade elevation below the new aggregate base. Sheet W-2, attached, shows the recommended removal limits and depth.
The excavation bottom should be observed by a representative of this firm to verify the exposed conditions are as anticipated. The bottom should then be proof-rolled with a pneumatic-tired roller or other loaded construction equipment and observed for deflection (pumping). Areas of soil with high moisture content may be present along the alignment that become unstable with excessive deflection during proof-rolling. If such soil is encountered, it should be allowed to dry until it is stable and does not deflect when loaded, unless otherwise directed by the Engineer
We appreciate the opportunity to work with you on this project. Please call if you have any questions or need any other information.
Sincerely,
Inland Foundation Engineering, Inc.
Allen D. Evans, PE, GE
Principal
ADE:sd
Distribution: Addressee
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Packet Pg. 494 Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06- W-2 4.1.c
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Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06- APPENDIX “E”
ESPLANADE AVENUE WIDENING PHASE 1
WARREN ROAD TO SANDERSON AVENUE
SOUTHERN CALIFORNIA
EDISON DRAWINGS
ADDENDUM 5
SOUTHERN CALIFORNIA EDISON DRAWINGS
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Packet Pg. 496 Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06- RAR 0250 PS 7105 600A / 120A - FC LOAD BREAK 2335285E 2335286E 4523709E 4523708E LOAD BREAK 2335279E 1/0 A
1/0 A
1/0 A
ESPLANADE AV
CAWSTON AV RAR 0250 PS 7105 600A / 120A - FC LOAD BREAK 2335285E 2335286E 4523709E 4523708E LOAD BREAK 2335279E 1/0 A
1/0 A
1/0 A
ESPLANADE AV
CAWSTON AV EXISTING SINGLE LINE EASTER 12KV % NELSON SUB PROPOSED SINGLE LINE EASTER 12KV % NELSON SUB EX: 4792411 NEW: 25KVA 120/240 1P Contact USA Dial 811 or 800-422-4133 UNDERGROUND SERVICE ALERT www.digalert.org/contact “ ”
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Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06-145)) Contact USA Dial 811 or 800-422-4133 UNDERGROUND SERVICE ALERT www.digalert.org/contact
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Attachment: Contract Docs and Specifications - SJ-222 (Esplanade Avenue Widening Phase 1 Warren Road to Sanderson Avenue (CIP# 06-145))