Appendix_F_-_24-1139.1_Geotech_Report_Washington_District_Utility_Final.pdf

FINAL GEOTECHNICAL REPORT Crawford Washington District Underground Utility Infrastructure Infill and Update Project File: 24-1139.1 West Sacramento, California November 25, 2025

APPENDIX III

Laboratory Test Results

FINAL GEOTECHNICAL REPORT

Washington District Underground Utility Infrastructure Infill and Update Project

West Sacramento, California

Prepared by:

Crawford & Associates, Inc.

4701 Freeport Boulevard Sacramento, CA 95822

November 25, 2025

Prepared for:

R.E.Y. Engineers, Inc.

905 Sutter St. #200 Folsom, CA 95630

Main:

(916) 455-4225 Corporate Office:

4701 Freeport Boulevard Sacramento, CA 95822 www.crawford-inc.com c Sacramento Chico Eureka Modesto Santa Rosa Seattle Ukiah

November 25, 2025 Crawford File No. 24-1139.1

Ms. Veronica Garcia-McGrew, PE Project Manager R.E.Y. Engineers, Inc.

905 Sutter St. #200 Folsom, CA 95630

Subject: Final Geotechnical Report

Washington District Underground Utility Infrastructure Infill and Update Project West Sacramento, California

Dear Ms. Garcia-McGrew, Crawford & Associates, Inc (Crawford) presents this Geotechnical Report for the Washington District Underground Utility Infrastructure Infill and Update project in West Sacramento, California. Crawford prepared this report in accordance with our June 26, 2024 agreement.

This report summarizes the geotechnical conditions as evaluated from field and laboratory test data and used in the development of the geotechnical design. The purpose of this report is to provide recommendations for use in project design, specifications, and construction.

Thank you for the opportunity to be part of your design team. Please contact us if you have questions or require additional information.

Sincerely, Crawford & Associates, Inc., Reviewed by

David P. Castro, PE Shawn Leyva, PE Project Manager Principal david.castro@crawford-inc.com shawn.leyva@crawford-inc.com

TABLE OF CONTENTS

1 INTRODUCTION

1.1 PURPOSE

1.2 SCOPE OF SERVICES

2 PROJECT DESCRIPTION

3 SITE GEOLOGY AND SEISMICITY

4 FIELD EXPLORATION

4.1 DRILLING AND SAMPLING

4.2 LOGGING

4.3 SAMPLER PENETRATION RESISTANCE (N-VALUE)

5 SUBSURFACE CONDITIONS

5.1 EXISTING PAVEMENT THICKNESSES

5.2 SUBSURFACE MATERIALS

5.3 GROUNDWATER

6 LABORATORY TESTS

7 CORROSION

8 LIQUEFACTION POTENTIAL

9 CONCLUSIONS

10 RECOMMENDATIONS

10.1 OPEN-TRENCH PIPELINE RECOMMENDATIONS

10.1.1 SOIL LOADS ON RIGID BURIED PIPES

10.1.2 THRUST RESTRAINT

10.1.3 COMPOSITE MODULUS OF SOIL REACTION

10.2 TRENCHLESS PIPELINE RECOMMENDATIONS

10.2.1 TRENCHLESS SHAFTS

10.2.2 NATIVE MODULUS OF SOIL REACTION

10.3 PAVEMENT SECTIONS

10.4 EARTHWORK

10.4.1 TRENCH BACKFILL

10.4.2 FILL PLACEMENT & COMPACTION

10.4.3 PIPE BEDDING

10.5 CONSTRUCTION CONSIDERATIONS

10.5.1 DEWATERING

10.5.2 EXCAVATABILITY

10.5.3 SHORING AND TEMPORARY CONSTRUCTION SLOPES

10.5.4 OVER-OPTIMUM SOIL MOISTURE

11 RISK MANAGEMENT

12 LIMITATIONS

LIST OF TABLES

Table 1: Project Summary Table 2: Summary of Subsurface Exploration Table 3: Existing Pavement Section Thicknesses Table 4: Groundwater Data from Explorations Table 5: Soil Corrosion Testing Summary Table 6: Estimated Composite Modulus Table 7: HMA Pavement Sections (R-Value = 17)

APPENDIX I

Figure 1: Vicinity Map Figure 2: Exploration Map Figure 3: Geologic Map Figure 4: Fault Map

APPENDIX II

Boring Log Legend Boring Logs

APPENDIX III

Laboratory Test Results

APPENDIX IV

City of West Sacramento Standard Detail: Trench Backfill

1 INTRODUCTION

1.1 PURPOSE

Crawford & Associates, Inc. (Crawford) prepared this Geotechnical Report for the Washington District Underground Utility Infrastructure Infill and Update project (Washington Project) in West Sacramento, California. This report provides geotechnical/geologic data, conclusions and recommendations to support the design of the new water, wastewater and fiber optic conduit.

At the time of this report, the final location(s) and details of the pipeline improvements have not been determined. The recommendations presented below are preliminary and will be updated in the final report after we have received updated plans and comments on this draft report.

1.2 SCOPE OF SERVICES

To prepare this report, Crawford:

• reviewed geologic, soils, and seismic maps pertaining to the site;

• discussed the project with Veronica Garcia-McGrew with R.E.Y. Engineers;

• drilled, logged, and sampled 23 exploratory borings within the proposed pipeline/fiber improvement areas in September and October 2024;

• performed laboratory testing on soil samples recovered from the test borings; and

• developed conclusions and recommendations based on the data and test results.

2 PROJECT DESCRIPTION

The Washington Project will rehabilitate and/or replace aging/undersized water and wastewater pipes within West Sacramento generally between Tower Bridge Gateway and B Street. We also understand the project includes the design of conduit for future placement of fiber optic lines.

Refer to Figure 1 for the Vicinity Map and Figure 2 Exploration Map in Appendix I for project limits. We summarize the proposed improvements in the table below.

Table 1: Project Summary

Pipeline Type

Approx. Total Lenth

(ft)

Diameter (in)

Pipe Material

Cover Depth

(ft) Water 1,800 8 to 12 PVC and DIP 2.51

Sewer 3,000 8 to 12 PVC 41

Fiber Optic 3,200 4 PVC 2

1. Assumed value from City Standards

2. DIP = ductile iron pipe

3. RCP = reinforced concrete pipe

We understand that open-cut trench construction is anticipated for most of the pipeline improvements. Trenchless crossings below the Union Pacific Railroad (UPRR) are anticipated at three locations as follows; two water pipeline crossings at boring A-24-004 at 6th Street and between borings A-24-006 and A-24-009 between 4th Street and D Street, and one fiber line crossing along 3rd Street between borings A-24-008 and A-24-010. The launching and receiving pit depths are assumed to be about 10 ft below existing ground elevation.

The elevations and depths at the bottom of the existing utility pipelines are unknown at the time of this report.

3 SITE GEOLOGY AND SEISMICITY

The project site is located in the Great Valley Geomorphic Province of California that includes the Sacramento Valley and is bounded by the Sierra Nevada on the east and the Coast Ranges on the west.

The relatively flat surface of the Sacramento Valley is underlain by alluvial, lacustrine, and marine sedimentary deposits that have accumulated as the structural trough formed and the adjacent mountain ranges were uplifted. The thickness of the sediments varies from a thin veneer along the valley margins to thousands of feet at the axis of the trough.

Published geologic mapping1 shows the site underlain by Quaternary levee and channel deposits (Qa) which generally consist of clay, silt and sand deposited during flood stages of major streams. A Geologic Map is included as Figure 3 in Appendix I.

No active fault traces are shown on the cited published mapping and the site is not within an Alquist-Priolo Earthquake Fault Zone2 for fault rupture hazard. California Geological Survey (CGS) considers a fault to be active if it has shown evidence of ground displacement during the Holocene period, defined as the last 11,000 years. Based on mapping by CGS3, the nearest active fault is the Holocene-age Clayton Fault, located about 49 miles southwest of the site.

CBC seimic parameters can be provided if needed for pipeline improvements. The site fault map is shown on Figure 4 in Appendix I.

4 FIELD EXPLORATION

For this project/study, Crawford retained Hanlon Drilling to drill and sample 23 test borings between September 30 and October 3, 2024 to characterize the subsurface conditions and obtain samples for laboratory testing. Hanlon Drilling used a CME 75 truck mounted rig to drill the borings. All borings completed for this studey were drilled with 4-inch solid stem auger.

A summary of the field explorations are provided below in Table 2.

Table 2: Summary of Subsurface Exploration

Roadway Boring

ID1

Completion Date

Approx.

Ground

Surface Elev.

(ft)

Boring Depth

(ft)

B Street A-24-001 10/1/24 25 11.5

1 Wagner, D. L., et al., Geologic Map of the Sacramento Quadrangle, California Geological Survey, Regional

Geologic Map No. 1A, Scale 1:250,000, 1981.

2 http://maps.conservation.ca.gov/cgs/informationwarehouse/index.html?map=regulatorymaps 3 Fault Activity Map of California (2010), https://maps.conservation.ca.gov/cgs/fam/

Roadway Boring

ID1

Completion Date

Approx.

Ground

Surface Elev.

(ft)

Boring Depth

(ft)

4th Street A-24-002 10/1/24 23 16.5

6th Street A-24-003 10/1/24 21 16.5

6th Street A-24-004 10/1/24 25 21.5

C Street A-24-005 10/1/24 21 16.5

4th Street A-24-006 9/30/24 24 21.5

3rd Street A-24-007 10/1/24 24 16.5

2nd Street A-24-008 10/4/24 33 21.5

D Street A-24-009 9/30/24 25 23.0

3rd Street A-24-010 9/30/24 27 21.5

2nd Street A-24-011 9/30/24 26 16.5

E Street A-24-012 10/3/24 22 16.5

6th Street A-24-013 9/30/24 20 21.5

7th Street A-24-014 10/2/24 20 16.5

F Street A-24-015 10/3/24 20 11.5

F Street A-24-016 10/3/24 20 11.5

F Street A-24-017 10/2/24 21 16.5

F Street A-24-018 10/2/24 23 16.5

G Street A-24-019 10/2/24 22 16.5

G Street A-24-020 10/1/24 20 11.5

5th Street A-24-021 10/3/24 20 11.5

3rd Street A-24-022 10/3/24 25 11.5

Riverfront St. A-24-023 10/3/24 35 11.5

(1) All borings were drilled with a CME 75 truck-mounted drill rig. An automatic hammer was used to sample the borings. The drillers reported a hammer efficiency of 78.7%.

4.1 DRILLING AND SAMPLING

The borings were drilled with 4-inch diameter solid-stem augers. Drive samples of soil were recovered from the borings by means of 2.0-inch O.D. Standard Penetration Test split-spoon sampler (ASTM D1586) without liners and a 3.0-inch O.D. “Modified California” split-spoon sampler (ASTM D3550) with 2.4-inch I.D. liners. The samplers were each advanced with the standard 350 ft-lb striking force using a 140-lb automatic hammer and a drop height of 30 inches. A hammer energy calibration test was not performed specifically for this project;

however, Hanlon Drilling reports an energy efficiency of 78.7% (CME 75 Truck).

Drive samples were typically collected at about 2.5 and 7.5 ft and at approximate 5 ft intervals below this depth, or as otherwise directed by the field engineer/geologist. At each test interval, the sampler was driven 18 inches (or until sampler refusal criterion was met), and the blows necessary to advance the sampler each 6-inches of penetration were recorded. The sample refusal criterion is defined as 50 or more blows with less than 6 inches of sampler advancement.

We planned the general location and depth of the borings for this study based on our discussions with R.E.Y. Engineers, Inc. We show our boring locations on Figure 2 in Appendix I.

We include a soil legend with descriptions and an explanation of the descriptive terms used to log the soil samples. The boring log legend and boring logs are found in the Appendix II. The 2024 test boring elevations are estimated from Google Earth data.

Selected portions of recovered soil samples from the driven samplers were retained in sealed containers for laboratory testing and reference. The bulk soil samples collected from the auger cuttings were placed in plastic bags for laboratory testing and reference. At the completion of drilling the borings were backfilled with cement grout in accordance with the county boring permit requirements.

4.2 LOGGING

The borings were logged consistent with the Unified Soil Classification System (USCS) and the Caltrans Logging Manual4. Groundwater was noted on the logs when encountered. Crawford’s Project Geologist Mr. Justin McNabb logged the test borings for this study.

4.3 SAMPLER PENETRATION RESISTANCE (N-VALUE)

The in-situ sampler penetration resistance (N-value) in blows per foot was recorded in the field to obtain an approximate measurement of the dynamic resistance of the soil. The N-value was recorded as the number of hammer blows required to drive the sampler the final 12-inches of the 18-inch sample interval, unless refusal was met.

The SPT resistance (SPT N-value) adjusted to 60% hammer energy (N60) is routinely used to provide an index of the apparent density of cohesionless soils and sometimes (albeit less reliably) to estimate the consistency of cohesive soils. The energy-corrected N60 value normalized for effective overburden stress referred to as (N1)60 is typically used to correlate soil strength parameters and bearing characteristics.

For a non-standard sampler (i.e., non-SPT sampler), the in-situ N-value was corrected to an Equivalent SPT N-value using Burmister’s Energy-Area Correction (1948), then adjusted to provide an Equivalent N60 and/or Equivalent (N1)60 value that can be correlated to soil strength and bearing characteristics for use in geotechnical analysis.

The in-situ (uncorrected) N-values are shown on the boring logs provided in Appendix II.

4Caltrans, Soil and Rock Logging, Classification, and Presentation Manual, 2010 Edition with 2018 Errata

5 SUBSURFACE CONDITIONS

5.1 EXISTING PAVEMENT THICKNESSES

Crawford measured the pavement sections at all test boring locations within the project limits.

We present existing pavement section thickness data in Table 3 below.

Table 3: Existing Pavement Section Thicknesses

Boring Number

Street Name

Asphalt Thickness

(in)

Aggregate Base

Thickness (in)

A-24-001 B Street 3 7 A-24-002 4th Street 3 8 A-24-003 6th Street 3 5 A-24-004 6th Street 3 15 A-24-005 C Street 4 6 A-24-006 4th Street 3 6 A-24-007 3rd Street 3 8 A-24-008 2nd Street 3 7 A-24-009 D Street 3 4 A-24-010 3rd Street 4 7 A-24-011 2nd Street 2 8 A-24-012 E Street 3 7 A-24-013 6th Street 4 7 A-24-014 7th Street 3 7 A-24-015 F Street 5 8 A-24-016 F Street 5 8 A-24-017 F Street 3 7 A-24-018 F Street 3 3 A-24-019 G Street 6 14 A-24-020 G Street 6 6 A-24-021 5th Street 4 8 A-24-022 3rd Street 7 12 A-24-023 Riverfront St. 4 14

5.2 SUBSURFACE MATERIALS

In general, the materials encountered in our test borings completed for this study are comprised predominately of interbedded layers of silty sand, poorly graded sand, silt with sand and sandy silt with local zones/layers of lean clay.

Near the anticipated UPRR trenchless crossings the apparent density of the granular soil layers varies from very loose to medium dense in the upper 20 ft (elev. 4 ft) and the consistency of the cohesive soil layers varies from stiff to very stiff from about 10 ft to 20 ft (elev. 17 to 7 ft) in test boring A-24-010.

Near the planned watermain pipelines (A-24-001, A-24-004, A-24-013, A-24-006, A-24-009, A- 24-020 and A-24-021); the apparent density of the granular soil layers varies from very loose to medium dense in the upper 10 to 15 ft (elev. 15 to 6 ft) with isolated cohesive soil layers with consistency ranging from stiff to very stiff in the upper 15 ft (elev. 5 ft).

Near the planned sewer pipelines (A-24-002, A-24-003, A-24-005, A-24-011, A-24-012, A-24- 014, A-24-017, A-24-018 and A-24-019); the apparent density of the granular soil layers varies from very loose to medium dense in the upper 10 to 15 ft (elev. 15 to 8 ft) with isolated cohesive soil layers with consistency ranging from stiff to very stiff in the upper 15 ft (elev. 5 ft).

Near the planned fiber pipelines (A-24-008, A-24-010, A-24-022 and A-24-023); the apparent density of the granular soil layers varies from very loose to medium dense in the upper 10 ft to 20 ft (elev. 25 to 7 ft) with isolated cohesive soil layers with consistency of stiff in the upper 10 ft to 20 ft (elev. 17 ft to 7 ft).

Refer to the Boring Logs in Appendix II for detailed soil descriptions, sampling methods, and blow count data.

5.3 GROUNDWATER

At the time of our explorations, groundwater was encountered only in the test borings as shown and summarized in Table 4.

Table 4: Groundwater Data from Explorations

Boring I.D.

Date of Reading

Surface Elevation

(ft)

Groundwater

Depth (ft) Elevation (ft) A-24-004 10/01/2024 25.0 15.0 10.0 A-24-005 10/01/2024 21.0 13.0 8.0 A-24-006 09/30/2024 24.0 15.0 9.0 A-24-009 09/30/2024 25.0 17.0 8.0 A-24-010 09/30/2024 27.0 20.0 7.0 A-24-013 09/30/2024 20.0 13.0 7.0 A-24-014 10/02/2024 20.0 11.0 9.0 A-24-017 10/02/2024 21.0 12.0 9.0 A-24-019 10/02/2024 22.0 13.0 9.0

We recommend the use of a design groundwater depth of 10 ft (elev. 8 ft) for this study.

Groundwater levels can fluctuate due to changes in precipitation, drainage feature levels, irrigation and other factors.

6 LABORATORY TESTS

The following laboratory tests were completed on representative samples obtained from the borings and generally adhere to the standards specified by ASTM, Caltrans (CTM), and American Water Works Association (AWWA):

• Moisture Content-Dry Density (ASTM D2216/D7263)

• No. 200 Wash (ASTM D1140)

• Plasticity Index (ASTM D4318)

• Resistance Value (CTM 301)

• Unconfined Compression (D2166)

• Redox Potential (ASTM G-200m)

• Sulfides (AWWA C105/A25.5)

• Soil Sulfate Content (CTM 417)

• Soil Chloride Content (CTM 422)

• Minimum Resistivity and pH of Soil and Water (CTM 643)

Laboratory results are provided in Appendix III.

7 CORROSION

Corrosion test results on subsurface material samples are summarized in Table 5.

Table 5: Soil Corrosion Testing Summary

Boring I.D. / Sample No.

Depth Interval

(ft) pH

Moisture Content

Minimum Resistivity (ohm-cm)

Chloride (ppm)

Sulfate (ppm)

Redox Potential

(mV) Sulfides

Presence A-24-002-1A 6.0 to 6.5 6.46 17.6 1,850 2.4 38.5 +299 Negative A-24-004-4A 11.0 to 11.5 6.64 6.8 1,960 29.6 60.1 +308 Negative A-24-007-2A 6.0 to 6.5 7.10 13.0 1,420 69.5 57.9 +297 Negative A-24-012-4A 11.0 to 11.5 7.44 10.5 2,950 3.8 35.9 +293 Negative A-24-015-3A 8.5 to 9.0 7.47 17.4 2,600 27.7 16.7 +293 Negative

The AWWA 10-point system5 was used to evaluate the potential for external corrosion potential on ferrous metals from the soil. In general, the results of the 10-point system analysis ranges from 2 to 6, based on corrosion test results shown in Table 5, indicating a non corrosive environment. However, the results of the 10-point system analysis at A-24-007-2A is 11 mostly due to the minimum resisivity below 1,500, indicating a corrosive environment at this test location.

According to ACI 3186, a sulfate content of less than 1,000 parts per million (ppm) is considered negligible regarding corrosion potential. A chloride content, per ACI 318, of less than 500 ppm is generally considered non-corrosive to reinforced concrete.

5 American Water Works Association (2018), Polyethylene Encasement for Ductile-Iron Pipe Systems, AWWA

C105/A21.5 6 American Concrete Institute (2019), Building Code Requirements for Structural Concrete, ACI 318

The AWWA criterion indicates a corrosive environment to ferrous metals and the ACI criteria indicate a non-corrosive environment to concrete at this site. The provided corrosion test results are only an indicator of corrosion potential. Corrosion potential can vary at different locations and/or depths. The designer should consult with a corrosion engineer if these values are considered significant to the design.

8 LIQUEFACTION POTENTIAL

Soil liquefaction can occur when saturated, relatively loose sand and specific soft, fine-grained saturated soils (typically within the upper 50 feet) are subject to ground shaking strong enough to create soil particle separation that results from increased pore pressure. This separation and subsequent pore pressure dissipation can lead to decreased soil shear strength and settlement.

Liquefaction is known to occur in soils ranging from low plasticity silts to gravels. However, soils most susceptible to liquefaction are clean sands to silty sands and non-plastic silts.

The potential for liquefaction at the site does exist due to the presence of shallow groundwater, regional seismicity and loose sandy soils encountered in the test borings.

9 CONCLUSIONS

Based on the data generated for this study, we conclude that the site conditions are suitable for construction of the proposed pipelines using open trench and trenchless techniques provided the recommendations presented below are followed. Key geotechnical considerations associated with design and construction of this project include:

• the presence of very loose sandy soils within planned excavations;

• excavation wall stability of the temporary trench excavations for pipeline construction;

• groundwater: excavations extending at or below a depth of about 10 ft (about elev. 8 ft) are expected to encounter groundwater and subsurface seepage during dry season construction;

• corrosive materials: testing on sample A-24-007-2A indicates a potentially corrosive soils environment to metal pipes. Refer to Section 7 in this report for testing result details; a corrosion engineer should be consulted if test values are considered significant.

The site is in an active seismic region and the potential for ground motions can be expected over the lifespan of the proposed improvements. Within the upper 20 ft we encountered groundwater and loose cohesionless sandy layers below the planned pipeline improvements, however we consider the potential for detrimental liquefaction to adversely impact the project is considered low due to the isolated/discontinuous loose sandy layers.

In our experience materials consisting of clean sands or sands with little fines have resulted in potential trench stability issues. We encountered similar sandy materials within the test borings in the upper 20 ft below ground surface (bgs). We emphasize the importance of geotechnical oversight during construction to address variation in subsurface conditions between our test borings.

Pipeline recommendations for installation using open trench and trenchless methods below the UPRR are provided below.

10 RECOMMENDATIONS

10.1 OPEN-TRENCH PIPELINE RECOMMENDATIONS

Generally, the open-trench portions of the pipeline should have a minimum of 2 ft of cover along the fiber segments of the pipeline, a minimum of 2.5 ft along the water segments and a minimum of 4 ft along the sewer segments according to the City of West Sacramento Standards and Specifications. We anticipate the pipeline to be installed using open trench methods except at the planned trenchless crossing locations below the UPRR.

10.1.1 SOIL LOADS ON RIGID BURIED PIPES

Due to the lack of ductility of rigid pipelines, the dead loads and associated strain are important to analyze. The soil deadload (WD) on the rigid pipeline in a trench may be evaluated by Marston’s Formula:

𝑊! = 𝐶"𝛾𝐵"#

Where:

𝐶" = load coefficient based on 𝐾$% 𝛾 = moist unit weight of backfill material (pcf) 𝐵" = width of trench at top of pipe (ft)

Use a moist unit weight of 120 pcf for the above calculation.

Similar to Composite Modulus of Soil Reaction, the backfill material and compaction, trench width, and installation depth are components to designing the pipeline. For an open cut installation with a ratio of the backfill depth to trench width at the top of the pipe (𝐻/𝐵") of at least 1 (i.e. backfill depth is greater than the trench width) and for a trench width at top of pipe no greater than 3 times the pipe diameter, Cd

7 may be calculated by:

𝐶" = 1 − 𝑒&#'$

2𝐾𝜇%

𝐾 = rankine’s lateral earth pressure coefficient 𝜇% = friction coefficient between fill material and sides of trench 𝐻 = backfill height above the pipe crown (ft)

The combined 𝐾𝜇% value is dependent on backfill type, compaction, and moisture content. Using the backfill recommendations in this report, the estimated 𝐾𝜇% values are 0.120 for clay, 0.130 for silt, and 0.150 for sands and aggregate base.

10.1.2 THRUST RESTRAINT

Unbalanced thrust forces develop in a pipeline due to internal pressures, particularly around change of direction in the pipeline alignment. For large diameter pipelines, these thrust forces are typically counteracted by frictional resistance along the pipe and restrained joints.

7 Concrete Pipe Design Manual, American Concrete Pipe Association (2011), pg 36

Restrained joints resist thrust forces through friction between the pipe and the soil surrounding

it. Per AWWA M11, the length of pipeline required to restrain each side of an alignment bend is:

𝐿 =

𝑃𝐴(𝑐𝑜𝑠∆)

𝜇(𝑊* +𝑊+ +𝑊,)

𝐿 = length of restrained or harnessed joints on each side of the bend or elbow (ft) 𝑃 = internal pressure (psi) 𝐴 = cross-sectional area of the pipe (in2) ∆ = bend or elbow deflection (degrees), 0° to 90° 𝜇 = coefficient of friction between the pipe and the soil 𝑊* = horizontal bends: two times the weight of the prism of soil over the pipe (lb/ft of pipe length) = vertical bends: weight of the prism of soil over the pipe (lb/ft of pipe length) 𝑊, = weight of the pipe (lb/ft) 𝑊+ = weight of the contained water (lb/ft)

The coefficient of friction between ductile iron/concrete pipe and the surrounding soil is modeled as: 𝜇 = 𝑡𝑎𝑛 (0.6𝜙), where 𝜙 is the soil friction angle. Assuming sandy backfill per City Standards and a friction angle of 32°, we recommend using a coefficient of friction of 0.35.

Thrust blocks may also be used if additional thrust resistance is needed. Thrust block design is governed by two factors – the total thrust force and the allowable passive pressure of the soil.

Using a factor of safety of 2 an allowable passive pressure of 135 pcf can be assumed for each pipeline segment for thrust block design, neglecting passive pressure contribution from the upper 12 inches of soil.

10.1.3 COMPOSITE MODULUS OF SOIL REACTION

Semi-rigid and flexible pipes are designed to withstand a certain amount of deflection from applied earth loads. One of the input parameters to pipe deflection equations is the Composite Modulus of Soil Reaction (E'). The E' value is influenced by native soil properties, backfill soil properties, and trench/pipe geometry.

The E' values have been estimated for initial backfill (embedment material/pipe zone) and for the anticipated native trench wall soils at the pipe spring-line (horizontal plane through the pipe center). Values of E' for native soils (E'n) and initial backfill materials (E'b) are used in combination to calculate flexible pipe deflections using either the Iowa (Spangler 1941) or US Bureau of Reclamation (USBR 1997) equations.

We summarize the estimated native soil, initial backfill/pipe zone material and composite modulus E” values at each test boring location in Table 4. The estimated modulus values for initial backfill (E'b) in the pipe zone assumes coarse clean sandy material for the water piping and crushed rock for the sewer piping compacted to at least 90 percent compaction, per ASTM D1557.

If the values in Table 6 result in excessive calculated lateral deflections in flexible pipes, consideration should be given to widening the trench to provide higher-modulus backfill along the side of the pipe. Alternatively, the designer could select an appropriate composite E’ value per the table below for each pipeline segment and type.

Table 6: Estimated Composite Modulus

Boring Number

Street Name

Pipeline Type

Pipe Cover

(ft) B/D

Ratio

Soil Class

Symbol

Native E'n

(psi)

Backfill E'b

(psi)

Composite E'

(psi) A-24-001 B Street water 2.5 3 SM 2000 1000 1100

A-24-002 4th Street sewer 4.0 4 CL 2000 1000 2000 A-24-003 6th Street sewer 4.0 4 SM 700 1000 1000 A-24-004 6th Street water 10.0 3 ML 750 N/A 7501

A-24-005 C Street sewer 4.0 4 ML 1000 1000 1000 A-24-006 4th Street water 10.0 3 SM 700 N/A 7001

A-24-007 3rd Street sewer 4.0 4 ML 700 1000 1000 A-24-008 2nd Street fiber 10.0 7 SP 2000 N/A 20001

A-24-009 D Street water 10.0 3 SM 700 N/A 7001

A-24-010 3rd Street fiber 10.0 7 CL 2000 N/A 20001

A-24-011 2nd Street sewer 4.0 4 SM 700 1000 1000 A-24-012 E Street sewer 4.0 4 CL 2000 1000 1000 A-24-013 6th Street water 10.0 3 CL 2000 1500 1550

A-24-014 7th Street sewer 4.0 4 ML 1250 1000 1000 A-24-015 F Street sewer 4.0 2 SM 700 1000 1000 A-24-016 F Street sewer 4.0 2 CL 1500 1000 1000 A-24-017 F Street sewer 4.0 4 ML 750 1000 1000 A-24-018 F Street sewer 4.0 4 SM 700 1000 1000 A-24-019 G Street sewer 4.0 4 ML 500 1000 1000 A-24-020 G Street water 2.5 3 SM 700 1000 1000 A-24-021 5th Street water 2.5 3 CL 1500 1000 1000 A-24-022 3rd Street fiber 2.0 7 SM 1000 1000 1000

A-24-023 Riverfront St. fiber 2.0 7 SP 2500 1000 1000

Notes; 1. Trenchless crossing B = trench width, D = pipe diameter

10.2 TRENCHLESS PIPELINE RECOMMENDATIONS

We understand at three UPRR crossings trenchless techniques are planned to be used to install the pipeline where traditional open-cut trenching methods are not feasible. Crawford completed five explorations (A-24-004, A-24-006, A-24-009, A-24-008 and A-24-010) near the trenchless crossing locations. We were unable to complete a boring south of A-24-004 and UPRR crossing due to construction activities during our field explorations, therefore we rely on test boring A-24- 009 data for both trenchless crossings at 6th and 4th Streets south of the UPRR.

In general, we encountered very loose to medium dense sandy soils in our explorations near the anticipated pipe depths of about 10 ft bgs that will be capable of supporting various trenchless installation methods such as horizontal auger bore, pipe ramming, micro tunneling, and horizontal directional drilling. The contractor is responsible for selecting appropriate trenchless installation methods. The chosen trenchless method should not cause differential settlement, surface soil heaving, or damage to existing facilities and utilities. The method and approach must maintain pipeline vertical and horizontal alignment within design tolerances.

At the trenchless crossing, launching and receiving shafts (pits) will need to be excavated to house the trenchless installation equipment if direct access trenchless methods (e.g., horizontal auger bore, pipe ramming, jack-and-bore, micro tunneling, etc.) are used instead of Horizontal Direction Drilling (HDD). With the advantage of shallower excavations, HDD comes with the disadvantage of needing substantial staging area to lay out the pipe prior to installation. Issues that may affect trenchless installation operations along the pipeline alignment include the depth of soil cover, existing surface facilities, existing underground utilities and the presence of loose soils susceptible to caving. Per Caltrans July 2008 Guidelines and Specifications for Trenchless Technology Projects a minimum cover of 6 ft is recommended.

10.2.1 TRENCHLESS SHAFTS

The receiving and launching pit depths are unknown at this time. With proper shoring in place, the base of the shafts should be reviewed to see if the in-situ soil is suitable for the trenchless installation equipment. If the soil is found to be unstable, excavate 1.5 ft of in-situ soil and place an 18” layer of Class II aggregate base course compacted to at least 95% relative compaction wrapped (bottom and top) in a nonwoven geotextile fabric layer (Mirafi S1000 or equivalent).

Using a safety factor of 2 an allowable passive pressure of 135 pcf can be assumed for the walls of the trenchless shafts. The above value for passive pressure is based on an average intact native soil unit weight of about 90 pcf and an average soil friction angle of 30 degrees.

Shoring should be designed to prevent material from entering the shaft during all construction operations. Dewatering will likely be necessary during excavation of the launching and receiving shafts.

Once the trenchless portion of the pipe is installed, the launching and receiving pits should be backfilled per the City of West Sacramento Standards.

10.2.2 NATIVE MODULUS OF SOIL REACTION

We understand that at the trenchless crossing location below the UPRR, the pipeline will be installed in such a way that trench backfill will not be placed. Therefore, soil reaction will be based on the native soil modulus only. Based on the geotechnical information presented herein, the E'n values are estimated for native clays and sands for the proposed pipelines in Table 6 above.

10.3 PAVEMENT SECTIONS

We completed three R-value tests (CTM 301) on bulk samples of near surface soil. Test results indicate R-values of 17 and 19 by stabilometer. Based on the R-value test results, we recommend a design R-value of 17 to account for potential variations in subgrade quality. Using an R-value of 17 and Chapter 600 of the Caltrans Highway Design Manual, 6th Edition, we recommend the following Hot Mix Asphalt (HMA) pavement sections presented in the table below.

Table 7: HMA Pavement Sections (R-Value = 17)

Traffic Index

Minimum Thickness (ft) HMA AB Total

5 0.20 0.75 0.95 6 0.25 0.95 1.20 7 0.30 1.15 1.45 8 0.40 1.25 1.65

Other flexible pavement structural sections -- typically involving variations in AB thicknesses --which satisfy basement soil requirements are available and can be provided, if desired.

The above pavement design assumes that free water will be absent from the structural section.

Suitable surface drainage is of particular importance to limit subgrade saturation and excess free water.

10.4 EARTHWORK

10.4.1 TRENCH BACKFILL

Trench backfill should be in conformance with City of West Sacramento Standard Specifications Standard Detail #110 (included in Appendix IV). Based on Section 12.09 of the City of West Sacramento Standard Specifications, trench backfill is specified with the following requirements per Caltrans Test Method (CTM) 202:

Initial Backfill

Sewer Piping: Crushed Rock

• 100% passing the 1 inch Sieve

• 90-100% passing the 3/4 inch Sieve

• 20-55% passing the 3/8 inch Sieve

• 0-10% passing the No. 4 Sieve

• 0-5% passing the No. 8 Sieve

Water and Fiber Piping: Sand

• 100% passing the 1/2 inch Sieve

• 50 Sand Equivalent minimum (CTM 217)

Select Backfill and Finish Backfill

• Caltrans Standard Class II AB (Method A)

Drain Rock (for stabilization only)

• 100% passing the 2 inch Sieve

• 90-100% passing the 1 ½ inch Sieve

• 20-55% passing the 1 inch Sieve

• 0-15% passing the 3/4 inch Sieve

• 0-5% passing the 3/8 inch Sieve

Shovel-slice or spade bedding beneath the haunches of the pipe. Smaller compaction equipment should be used and special care should be taken to properly compact beneath the haunches of the pipe.

In trench excavations deeper than 6 ft we recommend; cutback 2 ft laterally beyond the limit of the trench excavation and excavate 2 ft below finished grade to help mitigate settlement, compensate for “zone of influence” effects, and provide bridging over the trench backfill materials. For additional settlement mitigation consider using Class 2 Aggregate Base (per Caltrans “Standard Specifications”) within this zone.

10.4.2 FILL PLACEMENT & COMPACTION

The on-site soil may not be reused as trench backfill per City of West Sacramento Standard Sections 12.08 and 12.09. Trench backfill should meet the following requirements:

• No concentrations of organics, debris, and other deleterious materials.

• Maximum particle size of 2 inches.

• Backfill materials should conform to Section 9.4.3 in this report.

• Select Backfill Zone compacted to a minimum of 90% relative compaction per ASTM

D1557.

• Finished Backfill Zone shall consist of Caltrans Class II AB compacted to a minimum of

95% relative compaction per ASTM D1557.

• Compact drain rock backfill per Section 12.07 of the West Sacramento City Standards with a minimum of three passes per lift with compaction equipment. Maximum 8 inch loose lifts.

Unstable trench subgrade conditions may be encountered. Crawford should observe excavations and monitor unstable trench subgrade conditions, if encountered. Per City Standard Detail #110 drain rock can be used to stabilize trench base below the pipe bedding. Refer to Section 9.4.3 in the report for drain rock requirements.

Nuclear density testing should be performed on each lift of compacted fill to confirm compaction at a frequency of at least one test:

• per 300 feet for trench backfill;

• per 300 feet for roadway subgrade (<40 ft wide); and

• per 300 feet per side for roadway subgrade (≥40 ft wide).

10.4.3 PIPE BEDDING

Support the pipe on granular bedding, consistent with the provisions of the current pipe manufacturer and the City of West Sacramento Standard Sections 12.01, 12.05 and 12.09.

Native soils will contain a significant number of fines (passing #200 sieve) in the upper twenty feet, and will likely not meet the specifications for use as bedding material.

Soft unstable soils at the excavation bottom should be replaced with drain rock at least 6 inches deep or the pipe diameter divided by 4. Drain rock should meet the requirements in Section

9.4.3 in this report. If groundwater is encountered the trench should be kept dry prior to placing pipe bedding material and pipe installation.

For water pipelines, if drain rock is used to stabilize the trench bottom filter fabric should be installed between the pipe bedding and drain rock as shown by City Standard Detail #110.

Based on City of West Sacramento Standard Specifications, pipe bedding should meet the following requirements:

Sewer Piping: Crushed Rock

• 100% passing the 1 inch Sieve

• 90-100% passing the 3/4 inch Sieve

• 20-55% passing the 3/8 inch Sieve

• 0-10% passing the No. 4 Sieve

• 0-5% passing the No. 8 Sieve

Water and Fiber Piping: Sand

• 100% passing the 1/2 inch Sieve

• 50 Sand Equivalent minimum (CTM 217)

• Relative Compaction (CTM 216) ≥ 90%

• Filter fabric per City Standard Detail #110

10.5 CONSTRUCTION CONSIDERATIONS

10.5.1 DEWATERING

The bottom portion of the excavations are anticipated to encounter groundwater (below a depth of about 10 ft) during dry season construction. Adequate construction dewatering is expected to be achievable by means a well point system installed around the outside of the proposed excavation areas. The Contractor is responsible for design and implementation of a dewatering system and selecting the final system appropriate for their means and methods per City of West Sacramento Standard Specification Section 22.

10.5.2 EXCAVATABILITY

Based on the conditions observed in our subsurface explorations and our experience, the on-site soil should be excavatable with typical grading equipment such as scrapers, dozers, backhoes and excavators.

10.5.3 SHORING AND TEMPORARY CONSTRUCTION SLOPES

Due to the presence of loose sands within the planned excavation limits, trench walls will experience significant caving during construction. At a minimum, all shoring and temporary construction slopes should be in accordance with current OSHA requirements. Our data indicates OSHA Soil Type C will be encountered throughout the project alignments. Allowable slopes per OSHA requirements for Type C material is 1.5:1 (horizontal:vertical).

Depending on available access, the contractor will likely need to shore the existing roadways to accommodate traffic if there is insufficient room to properly slope the trench excavation.

The contractor is responsible for all shoring and temporary slope design based on actual excavation conditions encountered during construction. Shoring will need to be conducive to the contractor’s approach to managing groundwater (where needed) and the excavation.

10.5.4 OVER-OPTIMUM SOIL MOISTURE

Excessively over-optimum (wet) soil conditions can make proper compaction difficult or impossible. Wet soil is commonly encountered during the winter and spring months, or in excavations where ground water or perched ground water is encountered.

In general, wet soil can be mitigated by:

• Discing the soil during prolonged periods of dry weather,

• Over-excavating and replacement with drier material,

• Stabilization using aggregate and stabilization fabric or geo-grid.

11 RISK MANAGEMENT

Our experience, and that of our profession, clearly indicates the risks of costly design, construction, and maintenance problems can be significantly lowered by retaining the Geotechnical Engineer of Record to provide additional services during design and construction.

For this project, Crawford should be retained as the Geotechnical Engineer of Record to:

• Review and provide comments on the civil plans and specifications prior to construction.

• Monitor construction to check and document our report assumptions. At a minimum, Crawford should observe excavations and monitor unstable trench subgrade conditions.

• Observe material submittals and imported fill.

• Update this report if design changes occur, two years or more lapse between this report and construction, and/or site conditions have changed.

Should there be any change in the project or should subsurface conditions differ from those described in this report be encountered during construction, this office should be contacted/notified for evaluation and supplemental recommendations, as needed.

Crawford is not responsible for any other parties’ interpretation of this report and recommendations contained herein, as well as subsequent addendums, letters, and discussions. If others perform the construction observation, they should review this report and either accept the conclusions and recommendations herein as their own or provide alternative recommendations.

12 LIMITATIONS

Crawford performed services in accordance with generally accepted geotechnical engineering principles and practices currently used in this area. Do not use this report for different locations and/or projects without the written consent of Crawford. Where referenced, we used ASTM and Caltrans standards as a general (not strict) guideline only. We do not warranty our services.

Crawford based this report on the current site conditions. We assumed the soil and groundwater conditions are representative of the subsurface conditions on the site. Actual conditions will vary along the project alignment. Our scope did not include evaluation of flooding potential and aerial photograph review. Please contact Crawford if you would like an evaluation of one or more of these potentially damaging issues.

Logs of our explorations are presented in Appendix II. The lines designating the interface between soil types are approximate. The transition between soil types may be abrupt or gradual. Our recommendations are based on the final logs, which represent our interpretation of the field logs and general knowledge of the site and geological conditions. Modern design and construction are complex, with many regulatory sources/restrictions, involved parties, and construction alternatives. It is common to experience changes and delays. The owner should set aside a reasonable contingency fund based on complexities and cost estimates to cover changes and delays.

APPENDIX I

Figure 1: Vicinity Map

Figure 2: Exploration Map Figure 3: Geologic Map

Figure 4: Fault Map

0 25

Miles

0 2,000

Feet

Approx. Project Limits

1. Base Map: USGS Topographic Map Layer, ArcGIS Pro, ESRI

2. Insert Base Map: National Geographic Style, ArcGIS Pro, ESRI

References

Prj. No: 24-1139.1 10/23/2024Date:

Figure 1 Vicinity Map

West Sacramento, CA

Washington District Underground Utility Infrastructure

Infill and Update Project

Project Location

B ST

C ST

2ND ST

2N D

S T

6T H

S T

6T H

S T

I ST

D ST

1S T

ST

© 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TomTom

© 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TomTom

© 2024 Microsoft Corporation © 2024 Maxar ©CNES (2024) Distribution Airbus DS © 2024 TomTom Prj. No:

Date:

Washington District Underground Utility Infrastructure

Infill and Update Project

West Sacramento, CA 24-1139.1NORTH

Figure 2 Exploration Map

Source:

Basemap: AutoCAD Civil3D Geolocation Tool, using Bing Maps

11/22/2024

1"=400'

400'0

Legend

APPROX. WATER

BORING LOCATION

APPROX. SEWER

BORING LOCATION

APPROX. FIBER

BORING LOCATION

APPROX. WATER

LINE ALIGNMENT

APPROX. SEWER

LINE ALIGNMENT

APPROX. FIBER

LINE ALIGNMENT

A-24-001A-24-002

A-24-007

A-24-003

A-24-005 A-24-004 A-24-006

A-24-009

A-24-012 A-24-010

A-24-011

A-24-014

A-24-013

A-24-017 A-24-018

A-24-016 A-24-015

A-24-020

A-24-021

A-24-022

A-24-023

A-24-008

A-24-019

Prj. No:

Date:

24-1139.1NORTH

Figure 3 Geologic Map

Source:

Wagner, D.L.; Jennings, C.W.; Bedrossian, T.L., and Bortugno, E.J.; 1981, Geologic map of the Sacramento Quadrangle, California; California Division of Mines and Geology, Regional Geologic Map Series, Map 1A, Sheet 1 of 4, scale 1:250,000.

10/24/2024

0 5,000'

1"=5,000'

APPROX.

PROJECT

ALIGNMENT

Washington District Underground Utility Infrastructure

Infill and Update Project

West Sacramento, CA

Qb

Qr

Qr

Legend

Qa Levee and Channel Deposits (Quaternary)

Qb Basin Deposits (Quaternary)- Alluvium

Qr Riverbank Formation (Quaternary)-Alluvium

Note: The above formations are mapped within the immediate vicinity of the project site (approximately 0.5 miles). Refer to the source material for formation descriptions beyond the immediate site area.

Chabot fault

W est N apa fault

D a vis fa ult

Black Butte fault Williamsfault

Pinole fault

Arroyo

Aguague fault

M idway fault

Verona fault

Lakeview fault

M ohaw k Valley fault zone

Lagoon V alley fault

S oda C reek fault

B errocal fault zone Calerofault

Pilarcitos fault

C ordelia fault zone C oncord fault

San Andreas fault zone

Unnamed fault in California

Franklin fault

Moraga fault

Mission fault

S toney

C reek fault

D unnigan

H ills fault

Haskins Valley fault

Collayomifault zone

BottleSprings fault

Tolayfault

R e so rt fa u lt zone

Butano fault

Calaveras fault zone

G reenville fault zone

R io

V ista fault

F oothills fault system

G re at V al le y th ru st fa ul t s ys te m

San G regorio fault zone

Beaver

Creek fault

Foothills fault system

Mount Diablo thrust fault

San Josefault

Vernalis fault

Stanfordfault

C hico M onocline fault

C or ni ng fa ul t

Great Valley thrust fault system

M idland fault zone

Legend

Quaternary Fault (Age)

<150 Years Ago

<15,000 Years Ago

<130,000 Years Ago

<750,000 Years Ago

<1.6 Million Years Ago

Fault Location

Inferred

Moderately Constrained

Well Constrained 0 20

Miles

Project Location

1. Fault Data: USGS GIS Data

2. Base Map: National Geographic Style, ArcGIS Pro, ESRI

References

Prj. No: 24-1139.1 10/23/2024Date:

West Sacramento, CA

Washington District Underground Utility Infrastructure

Infill and Update Project

Figure 4 Fault Map

APPENDIX II

Boring Log Legend

Boring Logs

BORING LOG / TEST PIT

LEGEND AND SOIL DESCRIPTIONS

UNIFIED SOIL CLASSIFICATION (ASTM D 2487-06)

MATERIAL

TYPES

GROUP

SYMBOL

CRITERIA FOR ASSIGNING SOIL GROUP NAMES

SOIL GROUP

NAMES

PI PLOTS BELOW "A" LINE

LL (oven dried)<0.75/LL (not dried)

FINES CLASSIFY AS ML OR MH

FINES CLASSIFY AS CL OR CH

FINES CLASSIFY AS CL OR CH

FINES CLASSIFY AS ML OR MH

COARSE-

GRAINED

SOILS

>50%

RETAINED ON

NO. 200

SIEVE

FINE-

GRAINED

SOILS

>50%

PASSING

NO. 200

SIEVE

GRAVELS

>50% OF COARSE

FRACTION RETAINED

ON NO. 4 SIEVE

SANDS

<50% OF COARSE

FRACTION RETAINED

ON NO. 4 SIEVE

SILTS AND CLAYS

LIQUID LIMIT <50

SILTS AND CLAYS

LIQUID LIMIT >50

CLEAN

GRAVELS

<5% FINES

GRAVELS

WITH FINES

>12% FINES

CLEAN

SANDS

<5% FINES

SANDS

WITH FINES

>12% FINES

INORGANIC

INORGANIC

ORGANIC

ORGANIC

HIGHLY ORGANIC SOILS

PRIMARILY ORGANIC MATTER,

DARK COLOR, ORGANIC ODOR

Cu > 4 AND 1 < Cc < 3

Cu < 4 AND/OR 1 > Cc > 3

Cu > 6 AND 1 < Cc < 3

Cu < 6 AND/OR 1 > Cc > 3

PI PLOTS ON OR ABOVE "A" LINE

LL (oven dried)<0.75/LL (not dried)

GW

GP

GM

GC

SW

SP

SM

SC

CL

ML

OL

CH

MH

OH

PT

POORLY-GRADED GRAVEL

WELL-GRADED GRAVEL

SILTY GRAVEL

CLAYEY GRAVEL

WELL-GRADED SAND

POORLY-GRADED SAND

SILTY SAND

CLAYEY SAND

LEAN CLAY

SILT

ORGANIC CLAY OR SILT

FAT CLAY

ELASTIC SILT

PEAT

ORGANIC CLAY OR SILT

Auger or backhoe cuttings

SAMPLE TYPES

ADDITIONAL TESTS

- Consolidation

- Compaction Curve

- Corrosivity Testing

- Consolidated Undrained Triaxial

- Direct Shear

- Expansion Index

- Permeability

- Partical Size Analysis

- Plasticity Index

- Pocket Penetrometer

- R-Value

- Sand Equivalent

- Specific Gravity

- Shrinkage Limit

- Swell Potential

- Pocket Torvane Shear Test

- Unconfined Compression

- Unconsolidated Undrained Triaxial

CL-ML

PLASTICITY CHART

ML or OL

MH or OH

A

L

I

N

E

P L A S T I C I T Y

I N

D E X

P I

LIQUID LIMIT (LL)

NOTE: Cu=D /D Cc=(D ) / D xD

60 10

30 10 60

BLOW COUNT

The number of blows of a 140-lb. hammer falling 30-inches required to drive the sampler the last 12-inches of an 18-inch drive. The notation 50/0.4 indicates 4-inches of penetration achieved in 50 blows.

Shelby tube

Standard Penetration (SPT)

Modified California 2"

Rock core

GROUND WATER LEVELS

Water level at time of drilling

Later water level after drilling

U

I

N

E

20 30 40 60 70 80 90 100 11050

C o r

O

C

H o r

O

H

For classification of fine-grained soils and fine-grained fraction of coarse-grained soils.

Equation of "A"-line

Horizontal at PI=4 to LL=25.5, then PI=0.73 (LL - 20)

Equation of "U"-line

Vertical at LL=16 to PI=7, then PI=0.9 (LL - 8)

C

CP

CR

CU

DS

EI

P

PA

PI

PP

R

SE

SG

SL

SW

TV

UC

UU

GRAPHIC

SYMBOL

Bulk Sample

California Standard 2.5"

DavidCastro Logo nickanderson Rectangle nickanderson Rectangle

FIELD

EL

EV

AT

IO

N (ft

D

EP

TH

(f t)

SA

M

PL

E

SA

M

PL

E

N O

Bulk A

B

LO

W S

PE

R

IN

B

LO

W S

PE

R

F O

O T

PO

C

K

ET

PE

N

TS

F)

1.75

TO

RV

A N

E (T

SF

G R

A

PH

IC

L

O G

DESCRIPTION

ASPHALT CONCRETE(3")

AGGREGATE BASE(7")

SILTY SAND (SM); dense; brown; moist;

mostly fine SAND; some non-plastic to low plasticity fines; weak cementation.

SANDY lean CLAY (CL); stiff; dark brown;

moist; mostly medium to high plasticity fines;

some fine SAND.

SILTY SAND (SM); loose; light brown to brown; moist; mostly fine SAND; some non-plasticity to low plasticity fines.

Bottom of borehole at 11.5 ft bgs

R

EC

O

VE

RY

R Q

D

LABORATORY

PL

A

ST

IC

IT

Y

IN

D

EX

LI

Q

U

ID

LI

M

IT

M O

IS

TU

R E

D . D

EN

SI

TY

(P

C F)

P

A

SS

IN

G

SI

EV

E

D R

IL

L

M

ET

H O

D C

A

SI

N G

D

EP

TH

REMARKS

Easy drilling from 0-10'

LOG OF BORING A-24-001

PROJECT NO: 24-1139.1

PROJECT: Washington Underground Utility LOCATION: West Sacramento, CA COUNTY: Yolo CLIENT: R.E.Y. Engineers, Inc.

LOGGED BY: JLM

DEPTH OF BORING: 11.5 (ft)

BEGIN DATE: 10/01/2024

COMPLETION DATE: 10/01/2024

SURFACE ELEVATION: 25.0 (ft) SURFACE CONDITION: Asphalt WATER DEPTH: Not Encountered

READING TAKEN: N/A

HAMMER EFFICIENCY: 78.7 (%)

DRILLING CONTRACTOR: Hanlon Drilling DRILLING METHOD: Solid-Stem Auger DRILL RIG: CME-75 (Truck) HAMMER TYPE: Automatic; 140 (lbs); 30 (in) drop SAMPLER TYPE & SIZE: SPT (1.4" ID), Bulk, MCAL (2.4" ID) BOREHOLE DIAMETER: 4.0 (in) BACKFILL METHOD: Tremie Grout

Crawford & Associates, Inc.

4701 Freeport Blvd Sacramento, CA 95822

(916) 455-4225

PROJECT NO: 24-1139.1

PROJECT: Washington Underground Utility

BORING: A-24-001

ENTRY BY: JLM

CHECKED BY: DPC SHEET # 1 of 1

EV

AT

IO

N (ft

D

EP

TH

(f t)

SA

M

PL

E

SA

M

PL

E

N O

Bulk A

B

LO

W S

PE

R

IN

B

LO

W S

PE

R

F O

O T

PO

C

K

ET

PE

N

TS

F)

3.00

TO

RV

A N

E (T

A

PH

IC

L

O G

DESCRIPTION

ASPHALT CONCRETE(3")

AGGREGATE BASE(8")

SANDY lean CLAY (CL); very stiff; dark brown; moist; mostly medium plasticity fines;

some fine SAND.

SILTY SAND (SM); loose; brown; moist;

mostly fine SAND; some non-plasticity to low plasticity fines.

Medium dense.

Wet.

Loose.

Bottom of borehole at 16.5 ft bgs

R

EC

O

VE

RY

R Q

D

LABORATORY

PL

A

ST

IC

IT

Y

IN

D

EX

LI

Q

U

ID

LI

M

IT

M O

IS

TU

R E

20.1 D

. D

EN

SI

TY

(P C

F)

105.5

P

A

SS

IN

G

SI

EV

E

D R

IL

L

M

ET

H O

D C

A

SI

N G

D

EP

TH

REMARKS