GEOTECHNICAL INVESTIGATION REPORT NEW ALIGNMENT FOR … · Senior Staff Engineer Senior Geotechnical Engineer Cristiano Melo, PE, GE #2756 ... 2018 draft report for this project

ENVIRONMENTAL, GEOTECHNICAL, CONSTRUCTION SERVICES AND ANALYTICAL TESTING

GEOTECHNICAL INVESTIGATION REPORT

NEW ALIGNMENT FOR THE

NORTH MANTECA TRUNK SEWER

BSK PROJECT NO. G18-131-11L

PREPARED FOR:

NV5 1215 WEST CENTER STREET, SUITE 201

MANTECA, CALIFORNIA 95337

November 19, 2018

399 L indbergh Avenue

L ivermore CA 94551

P 925.315.3151

F 925.315.3152 www.bskassoc iates.com

November 19, 2018 BSK JOB No. G18-131-11L NV5 1215 West Center Street, Suite 201 Manteca, California 95337 ATTENTION: Ms. Jill Sylvester, PE ([email protected]) SUBJECT: Geotechnical Investigation Report

New Alignment for the North Manteca Trunk Sewer Manteca, California Dear Ms. Sylvester:

BSK Associates (BSK) is pleased to submit our geotechnical investigation report for the above-referenced

project. The enclosed report describes the geotechnical investigation performed and presents our

geotechnical recommendations for the design of the planned infrastructure and earthwork for the project.

In summary, it is our opinion that the site is suitable for the proposed construction provided that the

geotechnical recommendations presented herein are followed for design and construction of the project.

Due to the presence of shallow groundwater and predominantly loose to medium dense sand layers at

the site, excavations will need to be properly dewatered, sloped, and/or shored. Information on our

investigative methods, conclusions, and specific recommendations for the design of the planned

infrastructure and earthwork are contained in this report. Our report also discusses geologic hazards that

could affect the site during a future significant seismic event.

Conclusions and recommendations presented in the enclosed report are based on limited subsurface

investigation and our laboratory testing program. Consequently, variations between anticipated and

actual subsurface soil conditions may be found in localized areas during construction. If significant

variation in the subsurface conditions is encountered during construction, BSK should review the

recommendations presented herein and provide supplemental recommendations, if necessary.

Additionally, design plans should be reviewed by our office prior to their issuance for conformance with

the general intent of our recommendations presented in the enclosed report.

mailto:[email protected]

Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California iii

We appreciate the opportunity of providing our services to you on this project and trust this report meets

your needs at this time. If you have any questions concerning the information presented, please contact

us at (925) 315-3151.

Respectfully submitted, BSK Associates

Danaige Tower, EIT Carrie L. Foulk, PE, GE #3016 Senior Staff Engineer Senior Geotechnical Engineer Cristiano Melo, PE, GE #2756 Geotechnical Group Manager Distribution: Client (electronically via email) David Zensius, NV5 ([email protected])

mailto:[email protected]

Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California iv

Table of Contents

1. INTRODUCTION .......................................................................................................... 1

1.1 Project Description ......................................................................................................... 1

1.2 Purpose and Scope of Services ....................................................................................... 2

2. SITE INVESTIGATION ................................................................................................... 3

2.1 Previous Investigations ................................................................................................... 3

2.2 Current Investigation ...................................................................................................... 3

2.3 Laboratory Testing .......................................................................................................... 4

3. SITE CONDITIONS ....................................................................................................... 5

3.1 Site Description .............................................................................................................. 5

3.2 Geologic Setting .............................................................................................................. 5

3.2.1 Area Geology ...................................................................................................................... 5

3.2.2 Area Faults ......................................................................................................................... 5

3.3 Subsurface Conditions .................................................................................................... 6

4. DISCUSSIONS AND CONCLUSIONS ............................................................................... 8

4.1 Underground Utility Lines .............................................................................................. 8

4.2 Trenchless Utility Crossings ............................................................................................ 8

4.4 Temporary Dewatering .................................................................................................. 9

4.5 Geologic and Seismic Hazards ........................................................................................ 9

4.5.1 Seismic Shaking and Faulting ............................................................................................. 9

4.5.2 Expansive Soils ................................................................................................................... 9

4.5.3 Liquefaction and Lateral Spread ...................................................................................... 10

4.5.4 Dynamic Compaction/Seismic Settlement ....................................................................... 11

5. RECOMMENDATIONS ............................................................................................... 12

5.1 Manhole and Pipe Design ............................................................................................. 12

5.1.1 Foundation Bearing Support for Manholes and Pipes ..................................................... 12

5.1.2 Vertical Loads on Pipe ...................................................................................................... 12

5.1.3 Manhole Walls ................................................................................................................. 13

5.1.4 Pipe Foundation ............................................................................................................... 14

5.1.4.1 Rock Ballast and Filter Fabric Option ................................................................ 14 5.1.4.2 Modified Caltrans Class 2 Permeable Material Option .................................... 15

5.1.5 Pipe Bedding and Embedment ......................................................................................... 15

5.2 2016 CBC Seismic Design Parameters .......................................................................... 15

Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California v

5.3 Trenchless Utility Crossings .......................................................................................... 17

5.3.1 Pipeline Materials ............................................................................................................ 17

5.3.2 Trenchless Pipeline Installation Alternatives ................................................................... 17

5.3.3 Minimum Depth of Cover ................................................................................................. 17

5.3.4 Settlement Monitoring ..................................................................................................... 18

5.3.5 Contractor Selection ......................................................................................................... 18

5.4 Earthwork ..................................................................................................................... 18

5.4.1 Existing Utilities ................................................................................................................ 19

5.4.2 Site Preparation, Grading, and Compaction .................................................................... 19

5.4.3 Re-Use of On-site Soil and Imported Fill Material ............................................................ 20

5.4.4 Weather/Moisture Considerations .................................................................................. 21

5.4.5 Excavation, Shoring, and Backfill ..................................................................................... 21

5.4.6 Temporary Dewatering .................................................................................................... 23

5.5 Reconstruction of Swanson Road ................................................................................. 25

5.5.1 Pavement Section............................................................................................................. 25

5.5.2 Construction Considerations ............................................................................................ 25

5.5.3 Reuse of On-site Asphalt Concrete ................................................................................... 26

5.6 Corrosion ...................................................................................................................... 26

5.7 Plan Review and Construction Observation ................................................................. 27

6. ADDITIONAL SERVICES AND LIMITATIONS ................................................................ 28

6.1 Additional Services ....................................................................................................... 28

6.2 Limitations .................................................................................................................... 28

Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California vi

Plates and Appendices

PLATES

Plate 1 – Vicinity Map

Plate 2 – Site Plan

Plate 3 – Geologic Map

Plate 4 – Soil Profile at West Yosemite Avenue

APPENDIX A – Boring Logs

Plate A-1 – Unified Soil Classification System (ASTM D 2487/2488)

Plate A-2 – Soil Description Key

Plate A-3 – Log Key

Log of Borings B-9 through B-13

APPENDIX B – Laboratory Test Results

Plate B-1 – Atterberg Limits

Plate B-2 – Unconsolidated Undrained Triaxial Test

Plate B-3 through B-5 – Consolidated Undrained Direct Shear

Plates B-6 through B-10 – Sieve Analysis

Plate B-11 – R-Value Test

Corrosivity Analysis by CERCO Analytical (2 pages)

APPENDIX C – Subsurface Data from Previous Investigations

APPENDIX D –Summary of Compaction Recommendations

Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California 1

1. INTRODUCTION

This report presents the results of our geotechnical engineering investigation for the future North

Manteca Trunk Sewer project in Manteca, California. A Vicinity Map showing the location of the project

site is presented on Plate 1. Our investigation has been performed for and coordinated with NV5.

This report contains a description of our site investigation methods and findings, including field and

laboratory data. Based on these findings, this report presents conclusions regarding the geotechnical

concerns related to the planned improvements. It also provides recommendations for the design of the

planned infrastructure and construction considerations. Note that this final report supersedes the

information presented in our July 25, 2018 draft report for this project.

1.1 Project Description

The location of the planned infrastructure improvements is shown on the Site Plan, Plate 2. The project

will include mass grading and construction of utility lines up to 30 feet deep below the ground surface.

The utility lines that are to be constructed include a 12-inch potable water line approximately 1,300 feet

long, a 24-inch recycled water line approximately 5,100 feet long, a 54-inch trunk sewer line

approximately 4,200 feet long, and an approximately 150-foot long 36-inch trunk sewer line. The potable

water line is expected to be 5 to 7 feet below existing grade, the recycled water line is expected to be 5

to 13 feet below existing grade, and the 36- and 54-inch trunk sewer lines are expected to be 8 feet and

20 to 30 feet below existing grade, respectively. The new utility lines will be mostly constructed by cut

and cover methods except for two (2) trenchless crossings, which are anticipated to be installed by

microtunneling and/or bore and jack construction. These trenchless crossings will be as follows:

o Crossing #1 will be for the proposed 54-inch trunk sewer line and will be located where this utility

line will cross West Yosemite Avenue. The crossing will be approximately 25 to 30 feet deep below

existing grade and will cross under numerous existing underground lines running under West

Yosemite Avenue.

o Crossing #2 will be for the proposed 54-inch trunk sewer line and will be located where this utility

line will cross Airport Way. The crossing will be approximately 25 feet deep below existing grade

and will cross under several existing underground lines running under Airport Way.

As part of the project, the existing pavement section for Swanson Road will be demolished and

reconstructed. Also, numerous existing underground utility lines will be abandoned.

If the actual project differs significantly from that described above, specifically if the grading differs from

that we assumed above, we should be contacted to review and/or revise our conclusions and

recommendations presented in this report.


1.2 Purpose and Scope of Services

The purpose of this investigation was to explore and evaluate the subsurface conditions at the site in order

to provide geotechnical input for the design and construction of the planned improvements and the

associated earthwork for this project. The scope of services, as outlined in our February 6, 2018 proposal

(File Number: GL18-16362), consisted of subsurface investigation, laboratory testing, engineering

analysis, and preparation of this report.

This investigation specifically excludes the assessment of site environmental characteristics, particularly

those involving hazardous substances.


2. SITE INVESTIGATION

2.1 Previous Investigations

Previous investigations were performed near the project site in 2015 and 2016 by BSK Associates (BSK).

These investigations are presented in the following documents, which are listed from most recent to

oldest:

• BSK (2018), Geotechnical Investigation Report, North Manteca Trunk Sewer and Milo Candini

Drive Extension, 1215 West Center Street, Suite 201, Manteca, California, dated June 29, 2018

(File No. G16-127-11L)

• BSK (2016), Geotechnical Investigation Report, Manteca Water Quality Control Facility

Improvements, 2450 West Yosemite Avenue, Manteca, California, dated May 6, 2016 (File No.

G15-133-10L)

Plate 2 shows the locations of the previous borings proximate to the new alignment for the North Manteca

Trunk Sewer project and Appendix C presents relevant subsurface data and laboratory test results from

these reports. A discussion of the subsurface conditions encountered at the site is presented in the

“Subsurface Conditions” section of this report and took into consideration the subsurface data contained

in the previous reports listed above.

2.2 Current Investigation

A geotechnical field investigation was performed on June 21 and 22, 2018 to evaluate the subsurface

conditions at the site for the planned construction. This exploration consisted of drilling 5 borings (labeled

B-9 through B-13) at the approximate locations shown on Plate 2. The borings were drilled, using a truck-

mounted drill-rig to depths of approximately 35 to 40 feet below the existing ground surface (BGS).

Hollow-stem augers were used to drill the borings. Exploration GeoServices of San Jose, California was

subcontracted to provide drilling services. The borings were logged by a BSK field engineer who also

collected surficial bulk samples.

Prior to subsurface investigation, Underground Service Alert (USA) was contacted to provide utility

clearance. Several drilling permits were also obtained from the San Joaquin County Environmental Health

Department (County). Upon completion of the subsurface investigation, the borings were backfilled with

cement grout per the County permit requirements. The upper approximately 6 inches of borings located

in paved areas was patched with Quikrete. Excess soil cuttings generated during drilling were left in

unimproved areas of the site near the boring locations.

The locations of the borings were estimated by our field representative based on rough measurements

from existing features at the site. Elevations shown on the boring logs were based on the 90% Submittal

Plans provided to us by NV5, dated June 15, 2018, showing current ground surface elevations near our


borings. As such, the elevations and locations of the borings should be considered approximate to the

degree implied by the methods used.

Relatively undisturbed samples of the subsurface materials were obtained using a split barrel sampler

with a 2.5-inch inside diameter (I.D.) and a 3-inch outside diameter (O.D.) fitted with stainless steel liners.

In addition, a 1.4-inch I.D. Standard Penetration Test (SPT) sampler was driven at selected depths to obtain

disturbed samples. The samplers were driven 18 inches using a 140-pound, semi-automatic trip hammer

falling 30 inches. Blow counts for successive 6-inch penetration intervals were recorded on the boring

logs. After the samplers were withdrawn from the boreholes, the samples were removed, sealed to reduce

moisture loss, labeled, and returned to our laboratory. Prior to sealing the samples, strength

characteristics of the cohesive soil samples recovered were evaluated using a hand-held pocket

penetrometer. The results of these tests are shown adjacent to the sample locations on the boring logs.

Soil classifications made in the field from auger cuttings and samples were re-evaluated in the laboratory

after further examination and testing. The soils were classified in the field in general accordance with the

Unified Soil Classification System (Visual/Manual Procedure - ASTM D2488). Where laboratory tests were

performed, the designations reflect the laboratory test results in general accordance with ASTM D2487

as presented on Plate A-1. A Soil Description Key is presented on Plate A-2 and a key to the symbols used

in the boring logs is presented on the Log Key, Plate A-3. Sample classifications, blow counts recorded

during sampling, and other related information were recorded on the soil boring logs. Logs of borings B-9

through B-13 are presented in Appendix A. A discussion of the subsurface conditions encountered at the

site is presented in the “Subsurface Conditions” section of this report.

2.3 Laboratory Testing

Laboratory tests were performed on selected soil samples to evaluate their physical characteristics and

engineering properties. The laboratory testing program included dry density and moisture content, grain

size analysis, consolidated-undrained direct shear (DSCU), unconsolidated-undrained triaxial compression

(TXUU), and Resistance (R)-Value testing. Some of the testing was performed by Cooper Testing Labs of

Palo Alto, California. Most of the laboratory test results are presented on the individual boring logs. The

results of the TXUU, DSCU, grain size analysis, and R-Value tests are also presented graphically in Appendix

B.

Analytical testing was performed as part of our investigation on soil samples obtained from depths of

about 23½ and 13½ feet BGS at borings B-10 and B-12, respectively, to assist in evaluating the corrosion

potential of the on-site soils. The corrosivity testing was performed by CERCO Analytical of Concord,

California using ASTM methods as described in CERCO Analytical’s report. The corrosion results are

presented in Appendix B.


3. SITE CONDITIONS

3.1 Site Description

As shown on Plate 2, the project site extends over a wide area, including a portion of the Manteca WQCF,

farming land, residential streets, and undeveloped land. The project limits are approximately bounded to

the south by the Manteca WQCF, to the north by farming land, and to the east by farming land and Airport

Way. West Yosemite Avenue crosses the middle of the utility alignment. The project site is relatively flat

with site elevations ranging from about 20 to 28 feet according to the recent topographic survey maps

provided by NV5. Several dirt embankments/farming access roads crisscross the site.

3.2 Geologic Setting

3.2.1 Area Geology

The site area is located in the Great Valley geomorphic province just east of the San Joaquin River which

forms a broad syncline with deposits of marine and overlying continental sediments, Jurassic to Holocene

in age. The thickness of the sediments increases to the west and reaches a thickness of as much as 20,000

feet on the west side of the San Joaquin Valley syncline. East of the site area are the Sierra Nevada

Mountains consisting of Mesozoic folded metamorphic rocks and Mesozoic plutonic rocks. To the west

are the Coastal Ranges characterized by north-south trending ridges and valleys that are typically highly

folded with numerous faults.

As shown on the Geologic Map, Plate 3, the site area is situated on the Pleistocene Modesto Formation

(Wagner, 1991)1, which consists primarily of sand and gravel in the fan areas while clay, silt, and sand are

dominant in the inter-fan areas. The formation thickness ranges from a thin layer on the east side of the

valley to approximately 150 feet thick in the central part of the basin (CDWR, 2003)2.

The geologic setting described above is consistent with the subsurface conditions encountered by the

previous and current borings performed at the site and the surrounding site vicinity, which are discussed

in the “Subsurface Conditions” section below.

3.2.2 Area Faults

Seismically induced ground motion at a site can be caused by earthquakes on any of the sources

surrounding the site. Deaggregation of the seismic hazard was performed by using the USGS Interactive

Deaggregation website (USGS, 2008)3. The deaggregation determination, at the maximum considered

1 Wagner, D.L., Bortugno, E.J., and McJunkin R.D. (1991), Geologic Map of the San Francisco - San Jose Quadrangle, California Geological Survey, Regional Geologic Map No. 5A. 2 California Department of Water Resources (CDWR, 2003), California’s Groundwater, Bulletin 118. 3 USGS (2008), 2008 Interactive Deaggregations, http://geohazards.usgs.gov/deaggint/2008/

http://geohazards.usgs.gov/deaggint/2008/


earthquake (MCE) hazard level, results in distance, magnitude and epsilon (ground-motion uncertainty)

for each source that contributes to the hazard.

Results of the deaggregation based on a probabilistic model developed by the USGS (Dynamic:

Conterminous U.S 2008 (v3.3.1)) indicated mode magnitude of M6.54 at a distance of approximately 22

kilometers from the site.

3.3 Subsurface Conditions

Based on the findings obtained from our subsurface investigation performed on June 21 and 22, 2018, the

site is underlain primarily by interbedded layers of loose to medium dense fine grained silty sand and

poorly graded sand. Lesser interbedded layers of firm to hard clay and silt soils are also present. These

subsurface conditions are consistent with the findings from previous geotechnical investigations

performed proximate to the site which are discussed in the “Previous Investigations” section of this

report.

Free groundwater was encountered in all of our current borings and ranged from depths of about 14 to

18 feet BGS. Our 2015 and 2016 borings shown on Plate 2 encountered free groundwater at depths of

about 12 to 30 feet BGS. Ten (10) groundwater monitoring wells are located near the eastern end of the

project limits and their data is available at the State Water Resources Control Board’s GeoTracker website

(http://geotracker.waterboards.ca.gov) and summarized in the table below. Based on this information,

free groundwater near the northeast end of the project limits was measured at elevations ranging from

approximately 7 to 11 feet MSL between March and June 2015. Free groundwater near the intersection

of West Yosemite Avenue and Airport Way has been recorded as shallow as an elevation of approximately

15 feet MSL in March 2000 according to well MW-13 (T0607700558). Groundwater depth readings for

this well are available from March 2000 to June 2015 in GeoTracker. Groundwater elevations in this well

ranged from about 11 to 13 feet MSL from March 2012 to June 2015. In addition, according to the

California Department of Water Resources website (http://wdl.ca.gov.waterdalibrary), a monitoring well

(Station 377971N1212517W001) located at the intersection of West Yosemite Avenue and Airport Way

encountered free groundwater as shallow as an elevation of approximately 21 feet MSL in the mid- to late

1950’s. It should be noted that groundwater levels can fluctuate depending on factors such as seasonal

rainfall, groundwater withdrawal, and construction activities on this or adjacent properties.

http://geotracker.waterboards.ca.gov/

http://water.ca.gov.waterdalibrary/


SUMMARY OF GROUNDWATER ELEVATION DATA

Well Number Approximate Groundwater

Elevation (feet, MSL)1

Period of Groundwater Monitoring

MW-28 (T0607700558)

7.93 to 9.24 March to June 20152

MW-29 (T0607700558)


MW-30 (T0607700558)

9.77 to 10.73 March to June 20152

MW-31 (T0607700558)

9.62 to 10.51 March to June 20152

MW-32 (T0607700558)


MW-33 (T0607700558)


MW-34 (T0607700558)


MW-35 (T0607700558)

9.30 to 10.17 March to June 20152

MW-36 (T0607700558)

9.66 to 10.45 March to June 20152

MW-40 (T0607700558)

9.66 to 10.50 March to June 20152

Notes: 1. Groundwater elevation provided in the report entitled Second Quarter 2015 Sampling Report – Off-

Site Monitoring Well and Domestic Water Treatment System Sampling, Project Site “B”, Frank’s One Stop, 2072 West Yosemite Avenue, Manteca, Ca, Global ID No. T0607700558, dated July 23, 2015 by GHD, Inc. (GHD Job No. 03009-10006-37150) available on http://geotracker.waterboards.ca.gov.

2. Only data available.

The above is a general description of soil and groundwater conditions encountered at the site in the

previous and current borings. For a more detailed description of the soils encountered, refer to the boring

log data in Appendices A and C.

It should be noted that subsurface conditions can deviate from those conditions encountered at the

boring locations. If significant variation in the subsurface conditions is encountered during construction,

it may be necessary for BSK to review the recommendations presented herein and recommend

adjustments as necessary.

http://geotracker.waterboards.ca.gov/


4. DISCUSSIONS AND CONCLUSIONS

Based on the results of our field investigation, it is our opinion that the planned infrastructure

improvements are feasible geotechnically and that the project site may be developed as presently

planned. This conclusion is based on the assumption that the recommendations presented in this report

will be incorporated into the design and construction of this project.

Additional discussions of the conclusions drawn from our investigation, including general

recommendations, are presented below. Specific recommendations regarding geotechnical design and

construction aspects for the project are presented in the “Recommendations” section of this report.

4.1 Underground Utility Lines

Based on our findings, we conclude that the currently planned underground utility alignments are feasible

provided the recommendations contained in this report are properly implemented during design and

construction. We anticipate that excavations for the utility lines can be made with standard earthwork

equipment, such as excavators, dozers, backhoes, and trenchers. Because the site is underlain primarily

by silty to poorly graded sand, shoring or sloping of cut faces and trench walls will be necessary to protect

personnel and to provide temporary stability.

4.2 Trenchless Utility Crossings

As discussed in the “Project Description” section of this report, two trenchless utility crossings are

planned. Near Crossing #1, borings B-9 and B-10 encountered loose to medium dense, poorly graded to

silty sand with minor sandy lean clay layers within the expected depth of the crossing. Gravel and cobble

layers were not encountered in borings B-9 or B-10 within the maximum depth explored (approximately

40 feet BGS). Free groundwater was observed at a depth of about 18 feet BGS during drilling of borings B-

9 and B-10.

Plate 4 presents our interpretation of the soil profile for Crossing #1 under West Yosemite Avenue. This

profile is for illustrative purposes only and is based on interpolation between and extrapolation beyond

the borings advanced at the site. As such, this cross section should be considered approximate. Actual

subsurface conditions may vary and will need to be confirmed in the field during construction.

Near Crossing #2, boring B-8 encountered primarily silty to poorly graded sand within the anticipated

depth of the crossing. However, a well graded sand layer was also encountered at a depth of about 7½

feet BGS. Gravel and cobble layers were not encountered in boring B-8 within the maximum depth

explored (approximately 40 feet BGS). The upper sand layers tend to be loose to medium dense but

becomes denser with depth. Free groundwater was observed at a depth of about 23 feet BGS during

drilling of boring B-8.


Even though gravel layers were not encountered in our borings, gravel particles should be anticipated

within the sand layers. Sieve analysis and shear strength testing were performed on the samples collected

from our borings to aid in the design of the trenchless method(s) for the utility crossings. Based on our

findings, the planned trenchless crossings appear feasible from a geotechnical stand point provided

appropriate method(s) of installation are selected for the subsurface conditions anticipated. The

trenchless method(s) to be used should take into consideration the presence of shallow groundwater,

cohesionless soil layers, and cohesive soil layers underlying the site.

Note that the focus of our investigation for the trenchless crossings was to characterize the subsurface

conditions at these locations, evaluate their overall feasibility, and discuss possible constructability issues

that could occur during their construction. We understand that NV5 will design the trenchless crossings

and the excavation methods to be used. Due to the challenges associated with the presence of loose

cohesionless soils beneath the groundwater table, we recommend that experienced, specialty trenchless

contractor(s) be selected for the project.

4.4 Temporary Dewatering

As discussed in the “Subsurface Conditions” section of this report, groundwater can be shallower than 10

feet BGS near the project site’s vicinity. Therefore, we anticipate that excavations extending below this

depth will need to be continuously dewatered during construction.

4.5 Geologic and Seismic Hazards

4.5.1 Seismic Shaking and Faulting

We expect the site to be subjected to strong ground shaking during the life of the project. Therefore, the

design of pertinent underground and above-ground structures for the project should incorporate the

seismic design parameters presented in the “2016 CBC Seismic Design Parameters” section of this report

if applicable.

The site is not located within an Alquist-Priolo Earthquake Fault Zone and no mapped fault traces are

known to transverse the site. Therefore, we conclude that the potential for surface fault rupture to occur

across the site is very low.

4.5.2 Expansive Soils

The surficial soils are composed predominantly of fine grained silty sand with very low to low expansion

potential.


4.5.3 Liquefaction and Lateral Spread

Soil liquefaction is a condition where saturated, granular soils undergo a substantial loss of strength and

deformation due to pore pressure increase resulting from cyclic stress application induced by

earthquakes. In the process, the soil acquires mobility sufficient to permit both horizontal and vertical

movements if the soil mass is not confined. Soils most susceptible to liquefaction are saturated, loose,

clean, uniformly graded, and fine-grained sand deposits. If liquefaction occurs, foundations and

improvements resting above or within the liquefiable layer may undergo settlements and/or a loss of

bearing capacity.

Due to the nature of this project, it was not in our scope to evaluate the liquefaction potential at our

exploration points. However, based on the findings from BSK’s 2018 and 2016 reports referenced in the

“Previous Investigations” section of this report, depending on the depth of the open cut excavations for

the project, we expect that there is a low to moderate potential for the utility lines to be subjected to

liquefaction-induced settlements during a design-level earthquake. Upwards of 6 inches of liquefaction-

induced settlements were estimated during these previous investigations.

Mitigation of liquefaction hazards is typically not considered an economically viable option for roadways

and underground utility improvements as the cost of mitigation is typically much greater than the cost of

post-seismic event repairs. However, if desired, ground improvement methods that could be used to

mitigate the liquefaction-induced settlement of the site improvements could include removal and

replacement (i.e., excavation and recompaction of on-site soil), stone columns (or similar methods such

as Impact Rammed Aggregate Piers, IRAP), and compaction grouting.

For this project, most of the 54-inch trunk sewer line is expected to be installed using cut and cover

excavations extending to depths of about 25+ feet BGS. These excavations will be backfilled with on-site

soils to a dense, firm state, thus eliminating the presence of loose soils susceptible to liquefaction within

the backfill zone. According to the previous investigations referenced above, most of the potential

liquefiable layers are located at depths of less than 30 feet. Therefore, we anticipate that the liquefaction

potential within areas of the site to undergo cut and cover excavation to depth of 25+ feet BGS would be

low after the planned 54-inch trunk sewer line is installed.

Lateral spread is a potential hazard commonly associated with liquefaction where extensional ground

cracking and settlement occur as a response to lateral migration of subsurface liquefiable material. These

phenomena typically occur adjacent to free faces such as slopes, creek channels, and levees. The project

site is relatively flat. The closest canals are located at least 200 feet and 600 feet from the northeast and

west limits, respectively, of the underground utility alignment and the canals appear to be shallower than

the anticipated depth of the potential liquefiable layers. Therefore, we conclude that the potential for the

project improvements to be adversely affected by lateral spread is low.


4.5.4 Dynamic Compaction/Seismic Settlement

Another type of seismically induced ground failure, which can occur as a result of seismic shaking, is

dynamic compaction, or seismic settlement. Such phenomena typically occur in unsaturated, loose

granular material or uncompacted fill soils. The excavations for the planned utility lines will be 5+ feet

deep and will run underneath Swanson Road. Therefore, we conclude that the potential for seismic

settlement to occur underneath Swanson Road would be low because the excavation backfill below it

would be compacted to a dense, firm state.


5. RECOMMENDATIONS

Presented below are recommendations for the design of the underground utility lines, trenchless utility

crossings, seismic considerations, earthwork, pavement sections, and construction considerations for this

project.

5.1 Manhole and Pipe Design

5.1.1 Foundation Bearing Support for Manholes and Pipes

Manhole foundations should consist of concrete bases placed on firm, undisturbed soil or compacted

backfill. For manholes, the bearing pressures at which foundation soils will experience no net increase in

pressure are estimated at about 600, 1,200, 1,800, and 2,400 pounds per square foot (psf), for depths of

5, 10, 20, and 30 feet BGS, respectively. These pressures assume a groundwater depth of 10 feet BGS. In-

place densities of 110 to 130 pounds per cubic foot (pcf) may be assumed for existing in-situ soils and for

compacted soil backfill for use in estimating the weight of soil removed and of backfill placed. Should

loads greater than the weight of the material excavated be imposed on the surface or subsurface soils,

we should be contacted to evaluate the bearing capacity at the location of the proposed construction.

The bottom of pipe and manhole subgrades should be firm and stable, free of debris, loose soil or mud,

and free-standing water prior to concrete or pipe placement. In addition, clay soils exposed at the bottom

of the manhole excavations should not be allowed to dry out prior to placing concrete.

At locations where loose sands or soft soils are encountered at the proposed pipe and manhole subgrade

elevations, or where the subgrade soils are disturbed during construction, stabilization of the excavation

bottom may be needed. This could consist of a layer of rock ballast wrapped in filter fabric or the modified

Caltrans Class 2 permeable material, as recommended in the "Pipe Foundation" section of this report.

Selection of the stabilization method to be used should be based on the severity of the conditions present

during construction.

5.1.2 Vertical Loads on Pipe

The pipe selected should be capable of supporting vertical loads due to the soil overburden (trench

backfill) and surcharge, including traffic loads. An in-place density of 130 pounds per cubic foot may be

assumed for the trench backfill, and Marston's Formula4 may be used. The vertical pressure on the pipe

due to an H-20 live load, as defined in the "American Iron and Steel Institute, Handbook of Steel Drainage

and Highway Construction Products", may be taken as follows:

4 Marston, A, and Anderson, A.P., "The Theory of Loads on Pipes in Ditches and Tests of Cement and Clay Drain Tile and Sewer Pipe." Iowa Eng. Sta., Bull. No. 31 (1913).


VERTICAL LOADS ON PIPE

Height of Cover Over Pipe (Feet) Vertical Pressure on Pipe (psf)

1 1,800

2 800

4 400

6 200

8 100

>8 Neglect live load

Additional surcharge loads on the pipe should be considered in the design if the loads are located above

the pipe or within a 1H:1V (horizontal to vertical) plane projected upwards from the spring line of the

pipe.

5.1.3 Manhole Walls

We anticipate that the walls of standard manholes 10 feet or less in depth are capable of resisting the

lateral earth pressures and surcharge lateral loads due to normal H-20 roadway traffic expected at this

site. For manholes deeper than 10 feet, or those exposed to loads greater than H-20 loads, the design of

walls should be checked using the at-rest pressures discussed below and the anticipated surface loads.

We consider manhole walls to be relatively rigid so that they cannot yield sufficiently to develop active

earth pressures. For this relatively unyielding wall condition, an at-rest lateral earth pressure of 60 pounds

per cubic feet (pcf), expressed as an equivalent fluid pressure (unit weight), may be used for design. This

recommended pressure does not include hydrostatic pressure. We recommend that the manhole walls

be designed to resist both at-rest and hydrostatic pressures. Due to the presence of shallow groundwater

at the project site, a drainage system would require use of continuous pumping, which in our opinion

would make this alternative less feasible than designing the walls to resist hydrostatic pressures. If the

groundwater rises above the bottom of the manholes, the soils would become buoyant and the at-rest

lateral earth pressure should be increased to 90 pcf, which includes hydrostatic pressure. We recommend

that the buoyant at-rest pressure be used below a depth of 10 feet BGS.

Surcharge loads adjacent to the manholes should also be included in the design of the manhole walls. A

rectangular distribution acting over the upper 10 feet of depth of the walls with a pressure equal to one-

half of the surcharge load may be used.

Lateral loads may be resisted by a combination of friction between foundation bottoms and the

supporting subgrade, and by passive resistance acting against vertical faces of the structures. An allowable

friction coefficient of 0.35 between the foundation and supporting subgrade may be used. For passive

resistance, an allowable equivalent fluid pressure (unit weight) of 300 pounds per cubic foot (pcf) may be

used against the opposite wall of the manholes. If the groundwater rises above the bottom of the

manholes, the soils would become buoyant and the passive soil pressure should be reduced to 200 pcf.

We recommend that the buoyant passive pressure be used below a depth of 10 feet BGS. The friction and

passive values include factors of safety of about 1½.


Passive resistance in the upper one foot of the manhole walls should be neglected unless the ground

surface is confined by concrete slabs, pavements, or other such positive protection.

Section 1803.5.12 of the 2016 CBC requires that the design for foundation walls and retaining walls

supporting backfill heights greater than 6 feet include seismic earth pressures. Provided this requirement

applies to manhole walls, we recommend using seismic pressures of 30 pcf above a depth of 10 feet BGS

and 15 pcf below a depth of 10 feet BGS. These pressures are expressed as equivalent fluid pressures and

would be added to the wall design in addition to the static values presented above. The seismic earth

pressure should be applied as a triangular distribution with the resultant force acting at 1/3 times the wall

height above the base of the wall.

5.1.4 Pipe Foundation

Where pipe subgrade soils are firm and stable, free of debris, loose soil or mud, and free-standing water,

no pipe foundation material is needed. However, if loose sands or other soft or loose soils are encountered

at the proposed subgrade elevations for the pipeline and manholes, or where the subgrade soils are

disturbed during construction, we recommend that the pipe foundation consist of one of the options that

are listed below.

5.1.4.1 Rock Ballast and Filter Fabric Option

A layer of rock ballast wrapped in filter fabric (Mirafi 140N or equivalent) placed below the subgrade.

Before placing the rock ballast, the subgrade should be overexcavated a minimum of 9 inches below its

design elevation, followed by the placement of filter fabric.

The filter fabric should cover the entire width of the excavation at the locations where rock ballast is used,

and its seams should be fixed to the excavation walls before the placement of the rock ballast material.

Once these steps are accomplished, the overexcavated subgrade should be filled with rock ballast to

achieve a firm and stable surface. The rock ballast material should meet both of the following criteria:

• Consist of Class 1, Type B Permeable Material meeting the requirements of Section 68 of the 2010

Caltrans Standard Specifications; and

• Consist of crushed stone, or gravel, durable and free from slaking, or decomposition under action

of alternate wetting or drying.

Once the rock ballast is placed, the filter fabric seams should be detached from the walls of the excavation,

and wrapped around the rock ballast, and should overlap a minimum of one foot. Likewise, the filter fabric

seams for any consecutive sections of rock ballast placed longitudinally along the excavation should also

overlap a minimum of one foot.


5.1.4.2 Modified Caltrans Class 2 Permeable Material Option

In lieu of using rock ballast and filter fabric, the pipe foundation could consist of a layer, a minimum of 9

inches in thickness, of Caltrans Class 2 permeable material meeting the gradation requirements of Section

68 of the 2010 Caltrans Standard Specifications with the following modifications:

• The percentage by weight passing the No. 10 sieve should range between 15 and 33 percent; and

• The percentage by weight passing the No. 50 sieve should be limited to no more than 1 percent.

5.1.5 Pipe Bedding and Embedment

Pipe bedding should be placed for a thickness of at least 6 inches below the bottom of pipes and should

consist of on-site fine grained silty sand and/or poorly graded sand or import soil that meets the

requirements discussed in the “Re-Use of On-site Soil and Imported Fill Material” of this report unless

otherwise noted by the City of Manteca's Standard Specifications. The same material used as pipe bedding

may be used as pipe embedment (also known as shading), which is the material typically placed from the

top of the pipe bedding to 12 inches above the top of the pipe.

If the on-site fine grained silty sand and/or poorly graded sand is used as pipe bedding and shading, it

should be free of clay/silt clods, organics, and deleterious matter. It is important that the bedding and

shading material be free-flowing to enable complete support and coverage around the pipes prior to

compaction. If clayey soil or predominantly silt soil is encountered in the trench excavations, such material

should not be used as pipe bedding and shading because it is very difficult to compact it under the pipe

haunches.

Coarse-grained sand, gravel, and drain rock should be avoided as pipe bedding and/or embedment unless

the material is fully enclosed in a filter fabric, such as Mirafi 140N or equivalent. Otherwise, the native

fine grained silty sand and poorly graded sand to be used as excavation backfill above the pipe

embedment could potentially migrate into coarse grained or gap graded material causing loss of ground

and resulting in ground settlement. This could result in pipe joint movement and pavement distress.

If desired, pipe bedding and embedment material may consist of the modified Caltrans Class 2

permeable material specified in Section 5.1.4.2 above.

5.2 2016 CBC Seismic Design Parameters

Due to potential earthquake motion resulting from nearby faults, seismic design factors should be

considered in the design of structures for the project unless such structures are exempted by the

California Building Code (CBC).

Based on previous investigations near the site vicinity, the loose to medium dense sand layers and silt

layers are susceptible to liquefaction. Therefore, according to Table 20.3-1 of ASCE 7-10, the site should


be classified as Site Class F, which requires site response analysis. However, Sections 11.4.7 and 20.3.1 of

ASCE 7 state that for a short period (less than ½ second) structure on liquefiable soils, these factors may

be based on the assessment of the site class assuming no liquefaction. We anticipate structures for the

project will have a structural period of less than 0.5 seconds (BSK should be notified if that is not the case).

Therefore, Site Class D (stiff soil) is considered appropriate for this site.

Assuming a structural period less than 0.5 seconds for the proposed site structures, use of the 2016 CBC

mapped seismic design criteria is considered appropriate for this site and the following parameters should

be considered applicable for the design of structural improvements:

2016 CBC SEISMIC DESIGN PARAMETERS*

Seismic Design Parameter Value Reference

Site Class D Table 20.3-1, ASCE 7-10

MCER Mapped Spectral Acceleration (g) SS = 1.042 S1 = 0.366

USGS Mapped Values based on Figures 1613.3.1(1) and 1613.3.1(2), 2016 CBC

Site Coefficients Fa = 1.083 Fv = 1.667 Tables 1613.3.3(1) and 1613.3.3(2), 2016 CBC

MCER Mapped Spectral Acceleration Adjusted for Site Class Effects (g)

SMS = 1.129 SM1 = 0.611 Section 1613.3.3, 2016 CBC

Design Spectral Acceleration (g) SDS = 0.753 SD1 = 0.407 Section 1613.3.4, 2016 CBC

Seismic Design Category D Section 1613.3.5, 2016 CBC

MCEG peak ground acceleration adjusted for Site Class effects (g)

PGAM = 0.427 Section 11.8.3, ASCE 7-10

Definitions: MCER = Risk-Targeted Maximum Considered Earthquake MCEG = Maximum Considered Earthquake Geometric Mean *These seismic design parameters are based on the assumption that the proposed improvements have fundamental periods of less than about ½ second. If that is not the case, BSK should evaluate whether a site-specific response analysis is required.

As shown above, the short period design spectral response acceleration parameter, SDS, is greater than

0.5 and the long period design spectral response acceleration parameter, SD1, is greater than 0.2. These

values characterize the site as Seismic Design Category D as specified in Section 1613.3.5 of the 2016 CBC.

In accordance with Section 1613.3.5 of the 2016 CBC, each structure shall be assigned to the more severe

seismic design category in accordance with Table 1613.3.5(1) or 1613.3.5(2), irrespective of the

fundamental period of vibration of the structure.


5.3 Trenchless Utility Crossings

5.3.1 Pipeline Materials

Pipelines installed using pull-in-place trenchless techniques such as horizontal directional drilling (HDD)

most commonly are made of steel or high-density polyethylene (HDPE). Other materials that are less

common for pull-in-place trenchless installations include ductile iron and polyvinyl chloride (PVC).

Pipelines installed using a jacked-in-place method such as guided boring, jack and bore and

microtunneling may include reinforced concrete, steel, vitrified clay jacking pipe, or Hobas (centrifugally

cast, glass-fiber-reinforced, polymer mortar) pipe. For future maintenance, alignment/grade tolerance,

and other reasons, some applications use an oversized steel casing pipe with the carrier pipe installed

inside the casing. The annular space is generally filled with sand or grout following installation of the

carrier pipe.

Pipe materials are generally selected based on owner preferences, strength, internal and external

corrosion, roughness, availability, cost, and compatibility with preferred installation techniques. We

understand that preferred pipe material types have not yet been established.

In an HDD installation, the product pipe may be exposed to extra abrasion during pullback. When installing

a steel pipe, a form of coating which provides a corrosion barrier as well as an abrasion barrier is

recommended during the operation, the coating should be well-bonded and have a hard, smooth surface

to resist soil stresses and reduce friction, respectively. A recommended type of coating for steel pipes is

mill applied Fusion Bonded Epoxy according to the 2015 Caltrans Guidelines and Specifications for

Trenchless Technology Projects5.

5.3.2 Trenchless Pipeline Installation Alternatives

Selection of an appropriate trenchless installation technique for a particular location usually depends on

a number of factors including pipe material type and size, length and depth of run, subsurface conditions,

alignment and grade control tolerances, space constraints in the site vicinity, and environmental factors.

The selected trenchless method(s) should take into consideration the presence of shallow groundwater,

cohesionless soil layers, and cohesive soil layers underlying the site.

5.3.3 Minimum Depth of Cover

Based on the 2015 Caltrans Guidelines and Specifications for Trenchless Technology Projects, minimum

depths of cover of 10 and 15 feet BGS at the crossings should be considered. However, the actual depth

of cover selected will be influenced by the trenchless method selected.

5 Caltrans (2015), Caltrans Encroachment Permits, Guidelines and Specifications for Trenchless Technology Projects, dated January 2015.


5.3.4 Settlement Monitoring

Care should be exercised during installation of the trenchless crossings to avoid excessive loss of ground

which could propagate to the surface and cause settlement and distress to the pavement and surrounding

improvements at West Yosemite Avenue and Airport Way. Ground surface settlement monuments should

be established along and within a zone extending at least 30 feet to either side of the planned path of the

crossings at West Yosemite Avenue and Airport Way. The monuments should be located along the

shoulders and center left turn lane of West Yosemite Avenue and the shoulders and center of Airport

Way. The elevation of the monuments should be read prior to the start, throughout, and after the

trenchless operation is completed. During the trenchless operation, the monuments should be read on a

daily basis. Monitoring records should be made available to the City of Manteca and its consultants on a

daily basis during construction. If significant movement of the ground surface is noticed during the

trenchless operation, measures should be immediately taken to address any further loss of ground,

including, but not limited to, properly backfilling and abandoning the drill hole with grout or bentonite to

prevent future subsidence.

5.3.5 Contractor Selection

The successful construction of the trenchless crossings will be substantially determined by the experience

and performance of the specialty contractor(s) retained to perform the work. We recommend the use of

specialty contractor(s) with a minimum of 5 to 10 years of continuous construction experience in similar

drilling conditions on projects of similar scope (i.e., pipe diameter, pipe material, length, and depth) with

the specific trenchless method to be used by that contractor for this project. Contractor(s) to be

considered in the bidding process should provide examples of trenchless projects they have successfully

completed in the past 5 years installing similar utilities in similar conditions. The example projects should

note instances when things went wrong during particular projects and how they were remediated during

construction.

5.4 Earthwork

Earthwork at this project will generally consist of the following:

• Mass grading;

• Subgrade preparation;

• Placement of crushed rock underneath manholes;

• Excavation and backfill for the manholes and existing utilities to be relocated or abandoned, and

new underground utility lines; and

• Subgrade preparation and placement of aggregate base for the reconstruction of Swanson Road;

and

• Excavation and backfill of entry and exit shafts for trenchless excavation techniques.


We anticipate that the required grading will consist of cuts and backfills up to about 30 feet deep. Final

site grades are expected to remain relatively unchanged throughout the site. BSK should review the final

grading plans for conformance to our design recommendations prior to construction bidding. In addition,

it is important that a representative of BSK observe and evaluate the competency of existing soils or new

fill during construction. In general, soft/loose or unsuitable materials encountered should be over

excavated, removed, and replaced with compacted engineered fill material.

Site preparation and grading for this project should be performed in accordance with the site-specific

recommendations provided below. A summary of soil compaction recommendations for this project is

presented in Appendix D. Additional earthwork recommendations are presented in related sections of

this report.

5.4.1 Existing Utilities

Active or inactive utilities within the construction area should be protected, relocated, or abandoned.

Pipelines that are 2 inches or less in diameter may be left in place provided they are cut off and capped.

Pipelines larger than 2 inches in diameter should be removed or filled with a 1-sack sand-cement slurry

mix. Active utilities to be reused should be carefully located and protected during demolition and

construction activities at the site.

5.4.2 Site Preparation, Grading, and Compaction

Prior to the start of grading and subgrade preparation operations, the site should first be cleared and

stripped to remove all surface vegetation, organic-laden topsoil and debris generated during the

demolition of existing site improvements located within the project limits. Stripped topsoil from vegetated

areas may be stockpiled for later use in landscaping areas; however, this material should not be reused

for engineered fill.

Following stripping and removal of deleterious materials, the upper 12 inches (minimum) of the areas of

the site to receive fill should be scarified, moisture conditioned, and recompacted as indicated in Appendix

D, unless otherwise indicated by a BSK representative. Scarification and recompaction should extend

laterally a minimum of 2 feet beyond the limits of new fills, where achievable. If any undocumented fill is

encountered, the fill should be evaluated by a BSK representative and, if deemed necessary, removed and

replaced as engineered fill. All fills should be compacted by mechanical means in lifts of 8-inch maximum

uncompacted thickness. Jetting or ponding should not be permitted as a backfill compaction method

because these methods could result in very poor to poor relative compaction (due to the lack of

mechanical compaction) and cause significant settlement to occur at the site surface in the future. A

summary of compaction requirements for the project is presented in Appendix D. Laboratory maximum

dry density and optimum moisture content relationships should be evaluated based on ASTM Test

Designation D1557 (latest edition).


Subgrade soils, fill, and backfill, should be compacted to a minimum of 90 percent compaction at near

optimum moisture content. In paved areas, the upper 12 inches of the subgrade, and the aggregate base

above it, should be compacted to a minimum of 95 percent compaction at near optimum moisture

content. Where clayey soils are present, the soils should be moisture conditioned to at least 2 percent

above the optimum moisture content and the subgrade for pavements may be compacted to a minimum

of 93 percent compaction.

Most of the planned underground utility lines will be constructed using cut and cover excavation. These

temporary excavations are expected to be up to 30+ feet deep BGS. It will be critical to properly compact

the backfill for these excavations to reduce the potential for significant settlements to occur within their

limits. Because any settlement in these excavations will be differential relative to areas of the site not to

be excavated, consideration should be given to compacting all backfill below a depth of 7 feet below

finished grade to a minimum of 95 percent compaction where new or existing surface improvements are

located within a 1H:1V projection line extending up from the bottom of trench excavations.

Where access for compaction testing in deep excavations is limited due to trench stability, safety, and

other access concerns, sand-cement slurry or controlled density fill (CDF) may be considered as an

alternative to soil backfill if permitted by the City of Manteca. If this type of backfill material is used, the

utility lines should be anchored to prevent the pipe from floating. The slurry or CDF should be properly

vibrated to allow backfilling under the spring line of the pipes affected. If these types of backfill are

needed, consideration should be given to using the on-site sand material as part of the slurry or CDF.

Sand-cement slurry backfill typically consists of a 1- or 2-sack mix. CDF typically consists of a mixture of

cement, fly ash, coarse and fine aggregate, an air entrainment admixture and water. It should have a 28-

day compressive strength in the range of 50 pounds per square inch (psi), density in the range of 115 to

145 pounds per cubic foot (pcf), and a set time on the order of 4 to 6 hours. Such materials are locally

produced, and have been used successfully in several local jurisdictions where fast-setting, low-strength

backfill is needed. The proposed materials and method of construction should be reviewed by the City

and BSK prior to their approval and use.

All site preparation and fill placement should be observed by a BSK representative. During the stripping

process, it is important that our representative be present to observe whether any undesirable material

is encountered in the construction area and whether exposed soils are similar to those encountered

during our subsurface investigation.

5.4.3 Re-Use of On-site Soil and Imported Fill Material

From a geotechnical standpoint only, excavated on-site soils should considered suitable for re-use as

general engineering fill and backfill, provided organic materials are removed. Particles larger than 3 inches

within the on-site soils to be used as engineer fill should either be removed and disposed offsite or broken

down to 3 inches or less. Nesting (i.e., concentration) of larger particles should be avoided to reduce the

potential that this could create voids and allow future settlement in the overlaying fill/backfill.


Maximum particle size for fill material should be limited to 3 inches, with at least 90 percent by weight

passing the 1-inch sieve. Proper granular bedding and shading should be used beneath and around new

utilities except for segments to be installed using trenchless methods. In addition, imported fill should

adhere to the above gradation recommendations and conform to the following minimum criteria:

IMPORT FILL CRITERIA

Plasticity Index 15 or less

Liquid Limit Less than 30%

% Passing #200 Sieve 8 % – 40%

Corrosivity Refer to the “Corrosion” section of this report

Imported fill material should not be any more corrosive than the on-site soils and should not be classified

as being more corrosive than "moderately corrosive." If the imported fill is used to build the roadways off

of Swanson Road, it should have a minimum R-Value of 40.

Prior to transporting proposed import materials to the site, the contractor should make representative

samples of the material available to the geotechnical engineer at least 5 working days in advance to allow

the engineer enough time to confirm the material meets the above requirements. If prior corrosion testing

results are not available for the proposed import fill materials, then the samples should be made available

to the geotechnical engineer at least 10 working days in advance so that corrosion testing may be

conducted if this testing is deemed necessary. All on-site or import fill material should be compacted to

the recommendations provided for engineered fill in Appendix D.

5.4.4 Weather/Moisture Considerations

If earthwork operations and construction for this project are scheduled to be performed during the rainy

season (usually November to May) or in areas containing saturated soils, provisions may be required for

drying and/or stabilizing the soil through the use of scarification and air drying, geotextile fabric and dryer

soils, and/or via admixtures, such as lime- or cement-treatment of the soil prior to compaction.

Conversely, additional moisture may be required during dry months. Water trucks should be made

available in sufficient numbers to provided adequate water during earthwork operations.

5.4.5 Excavation, Shoring, and Backfill

We anticipate that excavations for new utility lines, manholes, entry and exit shafts, and the pavement

subgrade for the roadways off of Swanson Road can be made with standard earthwork equipment, such

as excavators, dozers, backhoes, and trenchers. Because the site is underlain primarily by silty to poorly

graded sand, shoring or sloping of cut faces and trench walls will be necessary to protect personnel and

to provide temporary stability.

All excavations made at the site should be evaluated to monitor stability prior to personnel entering them.

All trenches and excavations should conform to the current OSHA requirements for work safety. Based on


our findings, we anticipate that a maximum slope inclination of 1½H:1V for excavations up to 20 feet in

depth could be used at this site. However, it is the contractor’s responsibility to follow OSHA temporary

excavation guidelines and grade the slopes with adequate layback or provide adequate shoring and

underpinning of existing structures and improvements, as needed. Slope layback and/or shoring measures

should be adjusted as necessary in the field to suit the actual conditions encountered in order to protect

personnel and equipment within excavations.

Where the stability of adjoining embankments or structures could be endangered by excavation

operations, support systems such as shoring, bracing, or underpinning may be required to provide

structural stability and to protect personnel working within the excavation. The design and installation of

shoring, bracing, or underpinning required for the project should be the responsibility of the contractor

and should be designed by a professional engineer registered in the State of California. We recommend

that the proposed shoring, bracing, and underpinning system design be submitted (along with the

appropriate design calculations) in advance for review. The purpose of the review would be to evaluate

whether proper soil parameters have been used and to confirm whether the anticipated deflections are

within the tolerance established by the owner or its designer.

Due to the presence of predominantly fine grained silty sand and poorly graded sand layers underlying

the site, shored excavations will likely require use of continuous or solid-type shoring during excavation,

such as sheet piles. If soldier piles are to be used, continuous lagging will be necessary to prevent caving

of the excavation walls. Discontinuous, conventional shoring, such as trench boxes and hydraulic shores

with plywood/steel plates ("speed shores"), may not adequately support excavation walls because the

sand may not stand vertically long enough to move shoring into place following excavation. Discontinuous

shoring systems are not recommended for use in entry and exit shafts for trenchless excavation methods.

Shoring should be removed as the excavations are backfilled. Shoring should be designed to resist earth

pressures exerted by the retained soil plus any applicable surcharge loading, such as construction

equipment and stockpiles.

Excavations should be properly dewatered as discussed in the “Temporary Dewatering” section below.

Construction equipment and soil stockpiles should be set back a minimum horizontal distance of H away

from the edge of excavations, where H is equal to the depth of the excavation. This setback distance also

applies to shored excavations unless the shoring design takes into account any surcharge loads associated

with the construction equipment and stockpiles.

Care should be taken during construction to reduce the impact of trenching on adjacent structures and

pavements. Excavations should be located so that no structures, foundations, and slabs, existing or new,

are located above an imaginary plane projected 1H:1V upward from any point in an excavation unless the

excavation is properly shored and excavated in stages. If structures are located within this 1H:1V project

line, the shoring should be designed to handle the surcharge loading from the adjacent structure and

allow no horizontal movement of the excavation. Prior to the installation of the shoring and excavation,

monitoring points should be established immediately behind the shoring, at midway points between the

adjacent structure and the shoring, and at the edge of the adjacent structure. These points should be


surveyed daily during installation of the shoring and staged excavation. If any lateral movement is

detected, the excavation operation should be stopped immediately and measures should be taken to halt

further movement, such as placing a fill buttress in front of the shoring. The shoring design should then

be reevaluated and revised as needed. The design and installation of shoring, bracing, or underpinning

required for the project should be the responsibility of the contractor and should be designed by a

professional engineer registered in the State of California.

During wet weather, appropriate provisions, such as the use of earthen berms, should be made to prevent

water runoff from ponding adjacent to the top of excavations and/or flowing over the sides of the

excavations, otherwise the excavations side walls and/or slopes could be compromised. All runoff should

be collected and disposed of outside the construction limits. Backfill for excavations should be compacted

as noted in Appendix D. Special care should be taken in the control of excavation backfilling under

structures and pavements. Poor compaction may cause excessive settlements resulting in damage to

overlying structures and the pavement structural section.

5.4.6 Temporary Dewatering

Cut and cover excavation methods are planned for most of the new utility lines. These excavations will

extend to depths of 30+ feet BGS. We expect that excavations deeper than about 10 feet BGS (this is

equivalent to groundwater elevations of about 14 feet near boring B-3 (2016) and 12 feet near boring B-

8 (2016) will need to be continuously dewatered during construction depending on the time of the year.

However, based on monitoring well data and previous borings near the site vicinity, it is possible that

groundwater could be shallower than 10 feet BGS at the site during construction of the project,

especially during the raining season (typically November through May). The soils encountered within

the maximum depth of our exploration (about 40 feet BGS) consisted primarily of silty to poorly graded

sand layers, but lesser amounts of clay and silt layers were also present. Depending on their fines content

(i.e., amount of material passing the No. 200 sieve), sand layers typically have much higher transmissivity

rates than clay and silt layers. Groundwater should be lowered and maintained at least 2 feet below the

bottom of the planned excavations in order to maintain the undisturbed state of the supporting soils and

to allow proper compaction of backfill after below-grade structures and utility lines are installed. After

completion of all below-grade structures and utility lines, the dewatering operations may be terminated

to allow the groundwater table to return to its natural level.

During Phase 1 of construction (2016-2017) for the Family Entertainment Zone (FEZ) Infrastructure project

located approximately one mile south of the North Manteca Trunk Sewer project, dewatering was

employed to construct a 48-inch trunk sewer with open trench construction method. The FEZ trunk sewer

depth varied between approximately 20 and 25 feet BGS. We understand that with all the dewatering

pumps operating over the entire approximately 4,400-foot alignment, an average dewatering volume of

3 to 3½ million gallons per day was observed.

We anticipate that dewatering in the project area will be performed in stages and can be performed using

deep wells, well points, sumps, drains, and open pumping. However, because the subsurface conditions


consist of loose to medium-dense sand, slope stability and boiling at the bottom of the excavations could

pose a problem. The contractor should be fully responsible for developing and implementing a

dewatering program, including doing their due diligence to estimate the water quality and volume to

dewater this project. This should include making any necessary adjustments to the dewatering program

during construction based on actual field conditions encountered.

The successful implementation of the dewatering program for this project will be substantially

determined by the experience and performance of the contractor retained to perform the dewatering.

Therefore, we recommend that the general contractor for the project be required to retain the services

of a specialty dewatering subcontractor to review the anticipated subsurface conditions, and develop

and implement a proper dewatering program for the project. We recommend the use of a specialty

dewatering subcontractor with a minimum of 5 to 10 years of continuous construction experience in

similar subsurface conditions on projects of similar scope (i.e., depth of excavations, proximity to and type

of existing structures and utility lines, etc.). The dewatering subcontractor selected should provide

examples of dewatering for projects they have successfully completed in the past 5 years under similar

subsurface conditions and similar scope to this project. The example projects should note instances when

things went wrong during particular projects and how they were successfully remediated during

construction.

Temporary dewatering may cause ground subsidence that could result in adverse settlement of structures

near the areas being dewatered. Therefore, the dewatering subcontractor should evaluate the need to

install observation wells between existing structures and the dewatering activities to monitor changes in

groundwater levels. If dewatering-induced settlements are anticipated by the dewatering subcontractor,

it should consider implementing modifications to its dewatering program and possibly underpinning

existing structures (if allowed by the owner and/or its consultants). If underpinning is anticipated by the

dewatering subcontractor, prior to implementation of the underpinning, the project owner and its

consultants should review the underpinning plans to evaluate the assumptions made in the underpinning

design. This review should not be considered as relieving the dewatering subcontractor from full

responsibility for the underpinning plans and its satisfactory implementation.

In addition, consideration should be given by the dewatering subcontractor to installing ground surface

settlement monuments adjacent to structures located near areas of the site to be dewatered and

monitoring these monuments on a regular basis during dewatering activities. Monitoring records should

be made available to the owner and its consultants on a regular basis during construction. If significant

movement of the ground surface is noticed during or after the dewatering operation is completed,

measures should be immediately taken by the dewatering subcontractor to arrest the settlement. The

dewatering subcontractor should then develop and implement a plan for successfully mitigating the

settlement.

Consideration should also be given to performing video documentation and an existing conditions survey

of the nearby residences prior to and immediately after construction of the new underground utility lines

to be dewatered. The intent would be to capture existing conditions and monitor distress prior to and


during construction. This survey could be helpful if there are claims of damage by the nearby residents as

a result of the construction operations.

5.5 Reconstruction of Swanson Road

5.5.1 Pavement Section

We performed a Resistance (R)-Value test on a bulk sample collected at the ground surface of boring B-

11, which resulted in an R-Value of 59. Previous geotechnical investigations near the site have obtained

R-Value test results ranging from 50 to 75. Due to the potential variability of the silt content contained in

the surficial soils at the site, we recommend using an R-Value of 40 for design of the new pavement section

for Swanson Road.

Based on our discussions with NV5, we understand that Traffic Index (TI) values of 5.0 to 6.0 will be used

to design the pavement section for new residential driveways, while a TI value of 11 will be used to design

the pavement section for Swanson Road. The recommended pavement section is presented in the table

below and includes a factor of safety of 0.2 feet as per the Caltrans Design Manual.

ASPHALT CONCRETE PAVEMENT DESIGN FOR NEW RESIDENTIAL DRIVEWAYS

AND THE RECONSTRUCTION OF SWANSON ROAD

(R-VALUE = 40)

Traffic Index AC AB

5.0 2.5 5.0

5.5 3.0 5.0

6.0 3.0 6.0

11.0 7.0 12.5

Notes: Thicknesses shown are in inches. AC = Type A Asphalt Concrete AB = Class 2 Aggregate Base (Minimum R-Value = 78)

5.5.2 Construction Considerations

We recommend that the subgrade soil over which the future roadways are to be constructed be moisture

conditioned and compacted according to the recommendations in Appendix D. Subgrade preparation

should extend a minimum of 2 feet laterally beyond the road embankment limits.

On-site surficial sandy soils are considered suitable for use as engineered fill for the roadways. However,

care should be exercised during construction to avoid using soils resulting from deep excavations at the

site because these excavations will extend into layers that are sometimes composed primarily of silt and

clay, which typically have a much lower R-Value than the predominantly sand soils present at the ground

surface.


The pavement should be sloped and drainage gradients maintained to carry all surface water to

appropriate collection points. Surface water ponding should not be allowed anywhere on the site during

or after construction.

In addition, we recommend that all pavements conform to the following criteria:

• All excavation backfills should be properly placed and adequately compacted to provide a

stable subgrade, in accordance with the compaction recommendations in Appendix D;

• An adequate drainage system should be provided to prevent surface water or subsurface

seepage from saturating the subgrade soil;

• The asphalt concrete and aggregate base materials should conform to Caltrans Specifications,

latest edition; and

• Placement and compaction of pavements should be performed and tested in accordance to

appropriate Caltrans test procedures.

5.5.3 Reuse of On-site Asphalt Concrete

Existing asphalt concrete may be pulverized and mixed with the underlying gravel layer (i.e., aggregate

base) for use as general engineered fill if it meets the gradation requirements discussed in the “Re-Use of

On-site Soils and Imported Fill Material” section of this report.

Consideration should also be given to processing the existing asphalt concrete and underlying base for re-

use as Caltrans Class 2 aggregate base for provided it meets the gradation, R-Value, durability index, and

sand equivalent requirements of Section 26 of the 2015 Caltrans Standard Specifications, unless otherwise

indicated by the Geotechnical Engineer-of-Record during construction.

5.6 Corrosion

Samples of the subsurface soils at depths of approximately 13½ and 23½ feet below the existing ground

surface at borings B-12 and B-10, respectively, were submitted for corrosion testing. The samples were

tested by CERCO Analytical, a State-certified laboratory in Concord, California, for redox potential, pH,

resistivity, chloride content, and sulfate content in accordance with ASTM test methods. The test results

are presented at the end of Appendix B. Also included is the evaluation by CERCO Analytical of the

corrosion test results. Because we are not corrosion specialists, we recommend that a corrosion specialist

be consulted for advice on proper corrosion protection for underground piping which will be in contact

with the soils and other design details. Note that Appendix C also includes previous corrosivity test results.

Based upon the resistivity measurements, the samples tested are classified as "moderately corrosive to

corrosive" by CERCO Analytical. They recommend that all buried iron, steel, cast iron, ductile iron,

galvanized steel, and dielectric coated steel or iron be properly protected against corrosion depending

upon the critical nature of the structure. They also recommend all buried metallic pressure piping, such

as ductile iron firewater pipelines, should be protected against corrosion.


The above are general discussions. A more detailed investigation may include more or fewer concerns,

and should be directed by a corrosion expert. BSK does not practice corrosion engineering. Consideration

should also be given to soils in contact with concrete that will be imported to the site during construction,

such as topsoil and landscaping materials. For instance, any imported soil materials should not be any

more corrosive than the on-site soils and should not be classified as being more corrosive than

"moderately corrosive." Also, on-site cutting and filling may result in soils contacting concrete that were

not anticipated at the time of this investigation.

5.7 Plan Review and Construction Observation

We recommend that BSK be retained by the Client to review the 100 percent complete construction plans

and specifications before they go out to bid. It has been our experience that this review provides an

opportunity to detect misinterpretation or misunderstandings of our recommendation prior to the start

of construction.

Variations in soil types and conditions are possible and may be encountered during construction. To

permit correlation between the soil data obtained during this investigation and the actual soil conditions

encountered during construction, we recommend that BSK be retained to provide observation and testing

services during site earthwork. This will allow us the opportunity to compare actual conditions exposed

during construction with those encountered in our investigation and to provide supplemental

recommendations if warranted by the exposed conditions. Earthwork should be performed in accordance

with the recommendations presented in this report, or as recommended by BSK during construction. BSK

should be notified at least two weeks prior to the start of construction and prior to when observation and

testing services are needed.


6. ADDITIONAL SERVICES AND LIMITATIONS

6.1 Additional Services

The review of plans and specifications, and field observation and testing during construction by BSK are

an integral part of the conclusions and recommendations made in this report. If BSK is not retained for

these services, the Client will be assuming BSK’s responsibility for any potential claims that may arise

during or after construction due to the misinterpretation of the recommendations presented herein. The

recommended tests, observations, and consultation by BSK during construction include, but are not

limited to:

• review of plans and specifications;

• observations of site grading, including stripping and engineered fill placement;

• observation of grading activities for reconstruction of Swanson Road;

• observation of grading activities for cut and cover utility construction;

• observation of trenchless utility crossing construction; and

• in-place density testing of fills, backfills, and finished subgrades.

6.2 Limitations

The recommendations contained in this report are based on our field observations and subsurface

explorations, limited laboratory tests, review of available geologic maps and publications, review of

previous investigations near the site, and our present knowledge of the proposed construction. It is

possible that soil conditions could vary between or beyond the points explored. If soil conditions are

encountered during construction that differ from those described herein, we should be notified

immediately in order that a review may be made and any supplemental recommendations provided. If

the scope of the proposed construction, including the proposed loads or structural locations, changes

from that described in this report, our recommendations should also be reviewed.

We prepared this report in substantial accordance with the generally accepted geotechnical engineering

practice as it exists in the site area at the time of our study. No warranty, either express or implied, is

made. The recommendations provided in this report are based on the assumption that an adequate

program of tests and observations will be conducted by BSK during the construction phase in order to

evaluate compliance with our recommendations. Other standards or documents referenced in any given

standard cited in this report, or otherwise relied upon by the author of this report, are only mentioned in

the given standard; they are not incorporated into it or "included by reference", as that latter term is used

relative to contracts or other matters of law.

This report may be used only by the Client and only for the purposes stated within a reasonable time from

its issuance, but in no event later than two (2) years from the date of the report, or if conditions at the

site have changed. If this report is used beyond this period, BSK should be contacted to evaluate whether

site conditions have changed since the report was issued.


Also, land or facility use, on and off-site conditions, regulations, or other factors may change over time,

and additional work may be required with the passage of time. Based on the intended use of the report,

BSK may recommend that additional work be performed and that an updated report be issued.

The scope of work for this subsurface investigation and geotechnical report did not include environmental

assessments or evaluations regarding the presence or absence of wetlands at this site.

BSK conducted subsurface exploration and provided recommendations for this project. We understand

that BSK will be given the opportunity to perform a formal geotechnical review of the final project plans

and specifications. In the event BSK is not retained to review the final project plans and specifications to

evaluate if our recommendations have been properly interpreted, we will assume no responsibility for

misinterpretation of our recommendations.

We recommend that all earthwork during construction be monitored by a representative from BSK,

including site preparation, placement of engineered fill, trench backfill, and monitoring of trenchless

utility crossings. The purpose of these services would be to provide BSK the opportunity to observe the

actual soil conditions encountered during construction, evaluate the applicability of the recommendations

presented in this report to the soil conditions encountered, and recommend appropriate changes in

design or construction procedures if conditions differ from those described herein.

Geotechnical Investigation Report BSK Project No. G18-131-11L New Alignment for the North Manteca Trunk Sewer November 19, 2018 Manteca, California

PLATES

SITE

References: 1. http://google.com/maps, 2018

The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. BSK makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

AS SOC I A T E S1D. Tower

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Approximate Scale

Not to Scale

VICINITY MAP

New Alignment for the North Manteca Trunk Sewer

Manteca, California

W. Yo s e m i t e A v e n u e

References: 1. http://earth.google.com, 2018

Legend

Approximate Location of Current Borings

Approximate Location of Previous Borings (Year Performed)

Approximate Location of New Proposed Alignment

B-1

B-9

B-10

B-11

B-12 B-13

B-3 (2016)

B-1

B-7 (2016)

B-8 (2016)

B-1 (2015)

B-3 (2015)

B-4 (2015)


AS SOC I A T E S

SITE PLAN

2New Alignment for the

North Manteca Trunk SewerManteca, California

D. Tower

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SitePlan.indd

Approximate Scale1 in. 400 ft.

0 400

6/26/18

G18-131-11L

Crossing #1

Crossing #2

Qm

QsQdp

LEGEND

Qdp- Holocene Dos Palos Alluvium Qs- Holocene Dune Sand Qm- Pleistocene Modesto Formation

Reference: Geologic Map of California, San Francisco-San Jose quadrangles, 1991


AS SOC I A T E S

GEOLOGIC MAP



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Approximate Scale

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AS SOC I A T E S

20

10

0

-10

Silty Sand (SM)

Poorly Graded Sand (SP)/ Poorly Graded Sand with Silt (SP-SM)

Poorly Graded Sand (SP)/ Poorly Graded Sand with Silt (SP-SM)

Sandy Lean Clay (CL)

B-10 B-9

?

Notes & References

? ?

?

? ??

?

? ?

?

Swanson Road

B-10B-9

We

st

Yo

se

mit

e A

ve

nu

e

Silty Sand (SM)Sandy Lean Clay (CL)

?

Poorly Graded Sand (SP)

SOIL PROFILE AT WEST YOSEMITE AVENUE



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?

????

?

????

P

(

S

d?

(

d

C

S

M

S

B-1

?

Legend

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1 -


APPENDIX A

BORING LOGS


A S S O C I A T E S

UNIFIED SOIL CLASSIFICATIONSYSTEM (ASTM D 2487/2488)

A-1D. Tower

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Date:

File Name:

Checked By:

Project Number:

>

_

GRAVELSWITH >12%

FINES

SANDS WITH5 to 12% FINES

WELL-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE OR NO FINES

INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS

INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINESAND OR SILT

POORLY-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE FINES

WELL-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE CLAY FINES

GP

GM

(Liquid limit greater than 50)

GW-GMGW-GC

GP-GM

CLEAN GRAVELS

(More than halfof material

is smaller than

(More than halfof material

is larger thanthe #200 sieve)

COARSEGRAINED

MAJOR DIVISIONSTYPICAL

DESCRIPTIONS

SILTS AND CLAYSINORGANIC CLAYS-SILTS OF LOW PLASTICITY, GRAVELLYCLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS

GC-GM

CL-ML

OL

SOILS

SANDS

GW

GC

< _<Cu 4 and1 Cc 3

>

<>

<

GP-GC

SW

>12% FINES

SP

ML

CL

SILTS AND CLAYS

coarse fraction is smaller thanthe #4 sieve)

WITH <5%FINES

GRAVELSWITH 5 to 12%

FINES

Cu 4 and1 Cc 3

__ _<

>

<> >

Cu 4 and/or1 Cc 3

<>

CLEAN SANDS

(More than half of

is larger thanthe #4 sieve)

<> >

ORGANIC CLAYS & ORGANIC SILTS OF MEDIUM-TO-HIGHPLASTICITY

POORLY-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE CLAY FINES

OH

CHthe #200 sieve)

GRAINEDSOILS

ORGANIC SILTS & ORGANIC SILTY CLAYS OF LOWPLASTICITY

WELL-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE FINES

MH

POORLY-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE OR NO FINES

SILTY SANDS, SAND-GRAVEL-SILT MIXTURES

CLAYEY SANDS, SAND-GRAVEL-CLAY MIXTURES

CLAYEY SANDS, SAND-SILT-CLAY MIXTURES

INORGANIC SILTS AND VERY FINE SANDS, SILTY ORCLAYEY FINE SANDS, SILTS WITH SLIGHT PLASTICITY,

GRAVELS

WITH <5%FINES

SANDS WITH

coarse fraction

(More than half of

FINE

Cu 6 and1 Cc 3

(Liquid limit less than 50)

POORLY-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE CLAY FINES

POORLY-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE FINES

WELL-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE CLAY FINES

Cu 6 and/or1 Cc 3

WELL-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE FINES

POORLY-GRADED GRAVELS, GRAVEL-SANDMIXTURES WITH LITTLE OR NO FINES

SILTY GRAVELS, GRAVEL-SILT-SAND MIXTURES

CLAYEY GRAVELS, GRAVEL-SAND-CLAY MIXTURES

Cu 6 and1 Cc 3

Cu 6 and/or1 Cc 3

<

SW-SM

SW-SC

SP-SMSP-SC

SMSC

SC-SM

GRAPHICLOG

<_

_ _

>Cu 4 and/or1 Cc 3

<

CLAYEY GRAVELS, GRAVEL-SAND-CLAY-SILTMIXTURES

WELL-GRADED SANDS, SAND-GRAVEL MIXTURES WITHLITTLE OR NO FINES

__

__

>

<>

INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY,GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEANCLAYS

UNIFIED SOIL CLASSIFICATION SYSTEM (ASTM D 2487/2488)

UNIFIED SOIL CLASSIFICATIONSYSTEM (ASTM D 2487/2488)

Entry By:

Exhibit

B-1AT&T DATA CENTERPLANNED BLOOM ENERGY FUELS CELLS

2525 N. WATNEY WAYFAIRFIELD, CALIFORNIA

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G13-161-10P


A S S O C I A T E SA-2

SOIL DESCRIPTION KEY

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Project Number:

Very HardThe thread cannot be rerolled after reaching

Thumb will indent soil about 1/4 in. (6 mm)

Cohesive soil that can be broken down into small angularlumps which resist further breakdown

#10 - #4 Rock salt-sized to pea-sized#40 - #10 0.017 - 0.079" Sugar-sized to rock salt-sized

Flour-sized to sugar-sized

Weak

CRITERIA

High (H)

SR

Boulders

of sand scattered through a mass of clay; note thickness

DESCRIPTION

Inclusion of small pockets of different soils, such as small lenses

It takes considerable time rolling and kneeding

Same color and appearance throughout

Thumb will penetrate soil more than 1 in. (25 mm)

Thumb will penetrate soil about 1 in. (25 mm)

Thumb wil not indent soil but readily indented with thumbnail

Thumbnail will not indent soil

DESCRIPTION

Stratified

Laminated

Fissured

Slickensided

plastic limit.

Blocky

Lensed

Homogeneous

Strong

SA

A

ABBR

(# blows/ft)

Pea-sized to thumb-sized

the plastic limit. The lump or thread crumbles

limit. The lump or thread can be formed without

medium

Gravel

Particles are similar to angular description but have

Sand

Fines

coarse

fine

Passing #200

Thumb-sized to fist-sized

DESCRIPTION

DESCRIPTION

fine #200 - #10

ABBR

Angular

3/4 -3"

HP

MP

LP

NP

>12"

3/4 -3"

FIELD TESTFIELD TEST

Alternating layers of varying material or color with layersat least 1/4 in. thick, note thickness

to reach the plastic limit. The thread can bererolled several times after reaching the plastic

crumbling when drier than the plastic limit

DESCRIPTIONNone

Larger than basketball-sizedFist-sized to basketball-sized

Flour-sized and smaller<0.0029

Crumbles or breaks with considerable

CALIFORNIA

CRITERIA

Medium (M)

Subangular

LooseVery Loose

DENSITY

Rounded

Alternating layers of varying material or color with the layer

Rounded

LVL

Crumbles or breaks with handling or slight

Fracture planes appear polished or glossy, sometimes striated

Breaks along definite planes of fracture with little resistanceto fracturing

SIZE>12"

3 - 12' 3 - 12"

#4 - 3/4"

DESCRIPTION

Low (L) SF

VH

H

FIELD TEST

FIELD TEST

is required to reach the plastic limit.

<55 - 1515 - 4040 - 70

>70 85 - 10065 - 85

ABBR

Very DenseDense

Medium Dense

0.19 - 0.75"

Cobbles

SIEVESIZE

GRAINSIZE

APPROXIMATE

Particles have nearly plane sides but havewell-rounded corners and edges

Angular

Subangular

Subrounded


Particles have sharp edges and relatively planesides with unpolished surfaces

0.0029 - 0.017"

rounded edges

Damp but no visible waterVisible free water, usually soil is below water table

finger pressure

finger pressure

Will not crumble or break with finger pressure

DESCRIPTION

APPARENT

35 - 6515 - 350 - 15(%)

RELATIVEDENSITYSAMPLER

CONSISTENCY

Very SoftSoftFirmHard

Subrounded

VDD

MD

SPT(# blows/ft)

<44 - 1010 - 3030 - 50

>50

Particles have smoothly curved sides and no edges

No visible reactionSome reaction, with bubbles forming slowlyViolent reaction, with bubbles forming immediately

ABBR FIELD TEST

DryMoistWet

DMW

Non-plastic

coarse 0.079 - 0.19"

R

A 1/8-in. (3 mm) thread cannot be rolled at

The thread is easy to roll and not much time

Absence of moisture, dusty, dry to the touch

or thread cannot be formed when drier than the

any water content.The thread can barely be rolled and the lump

Weakly

Moderately

Strongly

ABBR

VS

less than 1/4 in. thick, note thickness

when drier than the plastic limit

Penetrated only a few inches with 1/2-inch reinforcing rod driven with 5-lb. hammerDifficult to penetrate a foot with 1/2-inch reinforcing rod driven with 5-lb. hammer

Difficult to penetrate with 1/2-inch reinforcing rod pushed by handEasily penetrated a foot with 1/2-inch reinforcing rod driven with 5-lb. hammer

Easily penetrated with 1/2-inch reinforcing rod by hand


FIELD TEST

>6035 - 6012- 355 - 12

<4(# blows/ft)SAMPLER

MODIFIED CA

Entry By:

Exhibit

GRAIN SIZE REACTION WITH HCL

CONSISTENCY - FINE-GRAINED SOIL

STRUCTURE

ANGULARITY

APPARENT / RELATIVE DENSITY - COARSE-GRAINED SOIL

MOISTURE CONTENT

CEMENTATION

PLASTICITY



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A S S O C I A T E SA-3

LOG KEY

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Date:

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Project Number:LOG KEY

GENERAL NOTES

ROCK CORE

LOG SYMBOLS

SEEPAGE

PI

CONTINUOUS CORE

-4

MC MOISTURE CONTENT(ASTM Test Method D 2216)

BULK / BAG SAMPLE

LIQUID LIMIT(ASTM Test Method D 4318)LL

PERCENT FINERTHAN THE NO. 200 SIEVE(ASTM Test Method C 117)

-200

SHELBY TUBE

UNCONFINED COMPRESSION(ASTM Test Method D 2166)UC

EXPANSION INDEX(UBC STANDARD 18-2)

TXUUUNCONSOLIDATED UNDRAINEDTRIAXIAL COMPRESSION(EM 1110-1-1906)/ASTM TestMethod D 2850

GROUNDWATER LEVEL(encountered at time of drilling)

COLLAPSE POTENTIALCOL

Boring log data represents a data snapshot.

This data represents subsurface characteristics only to the extent encountered at the location of the boring.

The data inherently cannot accurately predict the entire subsurface conditions to be encountered at the project site relative toconstruction or other subsurface activities.

Lines between soil layers and/or rock units are approximate and may be gradual transitions.

The information provided should be used only for the purposes intended as described in the accompanying documents.

In general, Unified Soil Classification System designations presented on the logs were evaluated by visual methods.

Where laboratory tests were performed, the designations reflect the laboratory test results.

EI

PLASTICITY INDEX(ASTM Test Method D 4318)

PERCENT FINERTHAN THE NO. 4 SIEVE(ASTM Test Method C 136)

STANDARD PENETRATIONSPLIT SPOON SAMPLER(2 inch outside diameter)

SPLIT BARREL SAMPLER(3 inch outside diameter)

SPLIT BARREL SAMPLER(2-1/2 inch outside diameter)

GROUNDWATER LEVEL(measured after drilling)

Entry By:

Exhibit



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107

100

1A1B1C

2A2B2C

3

4

5A5B5C

43

4

19

Silty Sand (SM): olive brown, moist, dense, fine to mediumgrained sand, decreasing silt content with depth, iron oxidestaining

Poorly Graded Sand with Silt (SP-SM): olive brown, moist,medium dense, fine to medium grained sand

Silty Sand (SM): olive brown, moist, medium dense, fine tomedium grained sand

olive brown mottled with light brownish gray

yellowish brown, fine to coarse grained sand

light brownish gray mottled with olive brown, increased siltcontent, fine to medium grained sand

Poorly Graded Sand (SP): light brownish gray, wet,medium dense, fine to coarse grained sand

Direct Shear (see plate B-3)

62935

989

59

12

766

71213

Completion Depth:Date Started:Date Completed:California Sampler:SPT Sampler:

Exploration GeoServices B-53Hollow Stem Auger140 lbs8-inches30-inches

40.06/21/186/21/182.5-inch inner diameter1.4-inch inner diameter

LOG OF BORING NO. B-9

Drilling Equipment:Drilling Method:Drive Weight:Hole Diameter:Drop:Remarks:

25 feetSurface El.:

Location: Grassy field

Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

5

10

15

20

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

er, T

SF

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

ten

t(%

)

Liqu

id L

imit

Project Name:Project Number:Project Location:Logged by:Checked by:

New Alignment North Manteca Trunk SewerG18-131-11LManteca, CaliforniaD. TowerM. Romero

MATERIAL DESCRIPTION

Sam

ple

s

Pen

etra

tion

Blo

ws

/ 6 in

ches

BSK Associates399 Lindbergh AvenueLivermore, CA 94551Telephone: (925)-315-3151Fax: (925)-315-3152

GE

O_T

AR

GE

T N

EW

ALI

GN

ME

NT

BO

RIN

G L

OG

S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18

106

6

7A7B7C

8

9A9B9C

0.5

22

Poorly Graded Sand with Silt (SP-SM): olive brown, wet,medium dense, fine to medium grained sand

increased silt content

Poorly Graded Sand (SP): light brownish gray, wet, dense,fine to coarse grained sand, silt content decreasing withdepth

Sandy Lean Clay (CL): dark gray mottled with brown, wet,firm, medium plasticity, fine grained sand, silt present

Boring terminated at approximately 40 feet. Freegroundwater was obverved at approxmately 18 feet. Boringbackfilled with cement grout.

91213

91330

91321

467






25 feetSurface El.:


Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

25

30

35

40

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

er, T

SF

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

ten

t(%

)

Liqu

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imit




Sam

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tion

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GE

O_T

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GE

T N

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ALI

GN

ME

NT

BO

RIN

G L

OG

S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18

112

83

90

1A1B1C

2

3A3B3C

4

5A5B5C

1.5

29

3

6

22

33

ASPHALT: approximately 1.5 inches of asphaltAGGREGATE BASE: approximately 2 inches of gravel,possibly aggregate baserock (FILL)Silty Sand (SM): yellowish brown, moist, loose, fine tomedium grained sand, iron oxide staining

medium dense, clay seamDirect Shear (see Plate B-4)

Poorly Graded Sand (SP): brown, moist, medium dense,fine to coarse grained sand

Lean Clay with Sand (CL): olive brown, wet, firm, mediumplasticity, fine to medium grained sand, high silt content

seam of poorly graded sandTXUU (see plate B-1) c= 1,490 psf

443

213

688

589

101715






26 feetSurface El.:

Location: Northbound Lane, Southernsection of Swanson Road

Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

5

10

15

20

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

er, T

SF

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

ten

t(%

)

Liqu

id L

imit




Sam

ple

s

Pen

etra

tion

Blo

ws

/ 6 in

ches


GE

O_T

AR

GE

T N

EW

ALI

GN

ME

NT

BO

RIN

G L

OG

S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18

6

7A7B7C

8

9A9B9C

4.0

6

Poorly Graded Sand with Silt (SP-SM): dark gray mottledwith brown, wet, medium dense, fine to medium grainedsand

decreased silt content

Lean Clay with Sand (CL): gray, moist, firm, mediumplasticity, fine to medium grained sand

Poorly Graded Sand (SP): gray, wet, dense, fine to coarsegrained sand


81018

39

14

46

15

92130






26 feetSurface El.:

Location: Northbound Lane, Southernsection of Swanson Road

Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

25

30

35

40

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

er, T

SF

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

ten

t(%

)

Liqu

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imit




Sam

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s

Pen

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tion

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/ 6 in

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GE

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GE

T N

EW

ALI

GN

ME

NT

BO

RIN

G L

OG

S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18

105

101

1

2A2B2C

3

4A4B4C

5

13

2

8

14

ASPHALT: approximately 1 inch of asphaltAGGREAGTE BASE: approximately 3 inches of gravel,possibly aggregate base (FILL)Silty Sand (SM): dark reddish brown, moist, loose, fine tomedium grained sand

R-Value= 59 (see Plate B-11)

brown, fine to coarse grained sand

Poorly Graded Sand with Silt (SP-SM): brown, moist,medium dense, fine to medium grained sand, iron oxidestaining

Poorly Graded Sand (SP): light brownish gray, very moist,medium dense, fine to medium grained sand

Direct Shear (see plate B-5)

wet, dense, fine to coarse grained sand

454

567

567

789

61222






24 feetSurface El.:

Location: Northbound Lane, Northernsection of Swanson Road

Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

5

10

15

20

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

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SF

% P

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ieve

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Sam

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GE

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GE

T N

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NT

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RIN

G L

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S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18

976A6B

7

8A8B8C

9

25

Poorly Graded Sand (SP): light brownish gray, very moist,medium dense, fine to medium grained sand (continued)

very dense, trace silt

brown mottled with dark gray, dense, increased coarsegrained sand

dark gray, medium dense

Lean Clay with Sand (CL): dark brownish gray, moist, firm,medium plasticity, fine to coarse grained sand

Poorly Graded Sand (SP): dark brownish gray, wet,medium dense, fine to medium grained sand, trace silt


2250/6"

81924

679

68

15






24 feetSurface El.:

Location: Northbound Lane, Northernsection of Swanson Road

Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

25

30

35

40

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

er, T

SF

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

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ure

Con

ten

t(%

)

Liqu

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Sam

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Pen

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tion

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ches


GE

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AR

GE

T N

EW

ALI

GN

ME

NT

BO

RIN

G L

OG

S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18

109

112

1A1B1C

2

3A3B3C

4

5A5B5C

>4.5

3.0

2

7

19

Silty Sand (SM): dark reddish brown, moist, mediumdense, fine grained sand

dark brownish gray, very dense, increased silt content, ironoxide staining, fine to medium grained sand

Sandy Lean Clay (CL): light brownish gray, moist, hard,medium plasticity, fine grained sand, iron oxide staining,high silt content

Poorly Graded Sand (SP): yellow mottled with gray, moist,dense, fine to coarse grained sand, iron oxide staining

Silty Sand (SM): brown, very moist, fine to coarse grainedsand

Lean Clay with Sand (CL): light brownish gray mottled witholive yellow, firm to hard, medium plasticity, iron oxidestaining

Poorly Graded SAND with Silt (SP-SM): light brownishgray, wet, dense, fine to coarse grained sand

56

11

303850/5"

103631

359

121633






21 feetSurface El.:


Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

5

10

15

20

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

er, T

SF

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

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ure

Con

ten

t(%

)

Liqu

id L

imit




Sam

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s

Pen

etra

tion

Blo

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/ 6 in

ches


GE

O_T

AR

GE

T N

EW

ALI

GN

ME

NT

BO

RIN

G L

OG

S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18

6

7A7B7C

8 3.5

Poorly Graded Sand (SP): light brownish gray, wet, verydense, fine to coarse grained sand (continued)

very dense, increased silt content

medium dense

Sandy Lean Clay (CL): olive gray, moist, hard, lowplasticity, fine grained sand


162140

51220

61012






21 feetSurface El.:


Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

25

30

35

40

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

er, T

SF

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

ten

t(%

)

Liqu

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imit




Sam

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s

Pen

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tion

Blo

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/ 6 in

ches


GE

O_T

AR

GE

T N

EW

ALI

GN

ME

NT

BO

RIN

G L

OG

S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18

26 11

97

86

1

2A2B2C

3

4A4B4C

5

3.0

1.75

56

3

18

36

37

Sandy Silt (ML): dark reddish brown, moist, non-plastic,fine grained sand

Silty Sand (SM): dark reddish brown, moist, loose, finegrained sand

yellowish brown, fine to coarse grained sand

Poorly Graded Sand (SP): light brownish gray, moist,medium dense, fine to coarse grained sand, trace silt

Silt with Sand (ML): dark brownish gray, moist, firm tohard, low to medium plasticity, fine to medium grained sand,iron oxide staining

TXUU (see plate B-1) c= 1,900 psf

Poorly Graded Sand (SP): brown, wet, medium dense, fineto coarse grained sand

121412

557

458

81012

91012






21 feetSurface El.:


Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

5

10

15

20

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

er, T

SF

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

ten

t(%

)

Liqu

id L

imit




Sam

ple

s

Pen

etra

tion

Blo

ws

/ 6 in

ches


GE

O_T

AR

GE

T N

EW

ALI

GN

ME

NT

BO

RIN

G L

OG

S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18

6

7A7B7C

8

Poorly Graded Sand (SP): brown, wet, medium dense, fineto coarse grained sand (continued)

very dense

medium dense

Sandy Lean Clay (CL): dark brownish gray, wet, firm,medium plasticity, fine grained sand, silt present


163050/4"

89

15

68

10






21 feetSurface El.:


Pla

stic

Lim

it

Pla

stic

ity In

dex

In-S

itu D

ry W

eig

ht(p

cf)

Dep

th, f

eet

25

30

35

40

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

ene

tro-

met

er, T

SF

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

ten

t(%

)

Liqu

id L

imit




Sam

ple

s

Pen

etra

tion

Blo

ws

/ 6 in

ches


GE

O_T

AR

GE

T N

EW

ALI

GN

ME

NT

BO

RIN

G L

OG

S.G

PJ

GE

OT

EC

HN

ICA

L 08

.GD

T 7

/24/

18


APPENDIX B

LABORATORY TEST RESULTS

0

LIQUID LIMIT (LL)

50

30

Inorganic clayey silts to veryfine sands of slight plasticity

10 100

UNIFIED SOIL CLASSIFICATIONFINE GRAINED SOIL GROUPS

20

Inorganic clays ofhigh plasticity

Inorganic clays of lowto moderate plasticity

Inorganic silts andclayey silts

EXPL

AN

ATI

ON

20

20

Dark Brownish Gray Silt with Sand (ML)

PLASTICITY CHART

C-1

26B-13 11

60

PI

Organic clays of moderate to highplasticity, organic silts

40

or

0

PLA

STIC

ITY

IND

EX (P

I)

80

Organic silts and organic siltyclays of low plasticity

100

50

DEPTH (ft)

40

7060

30

80

30

DESCRIPTION

60 7050

GROUPSYMBOL

LL PLLEGEND:

or

10 10

A-LINEU-LINE

90

90

14.0 37

SOURCE

1 of 1

PlateDate: 07-16-13

Entry By: J. Sala

File Name: 134350 blogs

Checked By: B. Steen

Project Number: 134350

SOUTHLAND MALLHEALTH CLUB

HAYWARD, CALIFORNIA

KA_

ATT

ER

BER

G

KA

CO

RPO

RAT

E S

TD.G

DT

KA

CO

RPO

RAT

E S

TD -

0920

11.G

LB

1343

50 B

LOG

S.G

PJ

7/1

7/13

CL

MH OH

OL

OH

MH

ML-CL ML

CH

CH

OL

ML

CL


A S S O C I A T E S

ATTERBERG LIMITS

B-1New Alignment for the


D. Tower

C. Melo

SitePlan.indd

7/24/18

G18-131-11L

Cooper Testing Labs, Inc.937 Commercial Street

Palo Alto, CA 94303

1 2 3 4Moisture % 33.1 35.6Dry Den,pcf 89.8 86.0Void Ratio 0.911 0.996Saturation % 99.9 98.3Height in 5.01 5.00Diameter in 2.42 2.42Cell psi 10.4 10.3Strain % 15.00 15.00Deviator, ksf 2.973 3.794Rate %/min 0.99 1.00in/min 0.050 0.050Job No.:Client:Project:Boring: B-10 B-13Sample: 5C 4CDepth ft: 19.5 14.5

Sample #1234

Note: Strengths are picked at the peak deviator stress or 15% strain which ever occurs first per ASTM D2850.

Remarks:

Sample Data

Visual Soil Description

Lean Clay with Sand (CL)Silt with Sand (ML)

664-204BSK AssociatesG18-131-11L

0.0

2.0

4.0

0.0 2.0 4.0 6.0 8.0

Shea

r Str

ess,

ksf

Total Normal Stress, ksf

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

0.0 6.0 12.0 18.0 24.0

Dev

iato

r Str

ess,

ksf

Strain, %

Stress-Strain CurvesSample 1

Sample 2

Sample 3

Sample 4

Unconsolidated-Undrained Triaxial TestASTM D2850


A S S O C I A T E S

UNCONSOLIDATED UNDRAINED TRIAXIAL TEST



D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L

CTL Job #: Project #: By: MDClient: Date: Checked: PJ

Project Name: Remolding Info:

Phi (deg) 43.2 Ult. Phi (deg)1 2 3 4

Boring: B-9 B-9 B-9Sample: 5C 5C 5C

Depth (ft): 19.5 19.5 19.5

Normal Load (psf) 1000 3000 5000Dry Mass of Specimen (g) 121.1 120.2 123.0Initial Height (in) 1.00 1.00 1.01Initial Diameter (in) 2.42 2.42 2.42Initial Void Ratio 0.680 0.695 0.678Initial Moisture (%) 18.6 20.3 17.5Initial Wet Density (pcf) 119.0 119.7 118.0Initial Dry Density (pcf) 100.3 99.5 100.5Initial Saturation (%) 73.9 79.0 69.7ΔHeight Consol (in) 0.0178 0.0174 0.0260At Test Void Ratio 0.650 0.665 0.635At Test Moisture (%) 20.4 20.6 19.7At Test Wet Density (pcf) 123.0 122.0 123.4At Test Dry Density (pcf) 102.1 101.2 103.1At Test Saturation (%) 84.9 83.5 83.8Strain Rate (%/min) 1.0 1.2 1.1Strengths Picked at Peak Peak PeakShear Stress (psf) 1666 3178 5422ΔHeight (in) at PeakUltimate Stress (psf)

©

Consolidated Undrained Direct Shear(ASTM D3080M)

BSK AssociatesNew Alignment North Manteca Sewer Tank

664-204 G18-131-11L7/12/2018

*DS-CU* A fully undrained condition may not be attained in this test. ΔH is not measured during undrained direct shear tests.

Light Brownish Gray Poorly

Graded Sand

Visual Description:


Graded Sand


Graded Sand

Remarks:

604

Specimen Data

Cohesion (psf) Ult. Cohesion (psf)

0

1000

2000

3000

4000

5000

6000

0.0 5.0 10.0 15.0 20.0 25.0

Shea

r Str

ess

(psf

)

Deformation (%)

Shear Stress vs. DeformationSample 1

Sample 2

Sample 3

Sample 4

0

2000

4000

6000

8000

0 2000 4000 6000 8000

Shea

r Str

ess,

psf

Normal Load, psf

Shear Stress vs. Normal LoadPeakShear StressUlt. StressUltimate

0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.20000.0 5.0 10.0 15.0 20.0 25.0

Del

ta h

(in)

Deformation (%)

Change in Height

Sample 1

Sample 2

Sample 3

Sample 4


A S S O C I A T E S

CONSOLIDATED UNDRAINED DIRECT SHEAR



D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L





Depth (ft): 9.5 9.5 9.5


©

1003

Specimen Data



YellowishBrown Silty

SAND

Visual Description:


SAND


SAND

Remarks:


BSK AssociatesNew Alignment Manteca Sewer Tank

664-204 G18-131-11L7/13/2018

0

500

1000

1500

2000

2500

3000

3500

0.0 5.0 10.0 15.0 20.0 25.0

Shea

r Str

ess

(psf

)

Deformation (%)


Sample 2

Sample 3

Sample 4

0

2000

4000

6000

8000

0 2000 4000 6000 8000

Shea

r Str

ess,

psf

Normal Load, psf


0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.20000.0 5.0 10.0 15.0 20.0 25.0

Del

ta h

(in)

Deformation (%)

Change in Height

Sample 1

Sample 2

Sample 3

Sample 4


A S S O C I A T E S




D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L




Boring: B-11 B-11 B-11Sample: 4B 4B 4B

Depth (ft): 14.0 14.0 14.0


©


BSK AssociatesNew Alignment Northh Manteca Sewer Tank

664-204 G18-131-11L7/13/2018



Graded Sand

Visual Description:


Graded Sand


Graded Sand

Remarks:

1100

Specimen Data


0

1000

2000

3000

4000

5000

6000

0.0 5.0 10.0 15.0 20.0 25.0

Shea

r Str

ess

(psf

)

Deformation (%)


Sample 2

Sample 3

Sample 4

0

2000

4000

6000

8000

0 2000 4000 6000 8000

Shea

r Str

ess,

psf

Normal Load, psf


0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.20000.0 5.0 10.0 15.0 20.0 25.0

Del

ta h

(in)

Deformation (%)

Change in Height

Sample 1

Sample 2

Sample 3

Sample 4


A S S O C I A T E S




D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L

Client: Project No.:Project: Boring Number:

Tested By: Sample ID:Reviewed By: Sample Depth:

Date Tested:

Coarse Medium Fine

- 3 67 27

Description of Soil: Poorly Graded Sand (SP)

Silt (non-plastic) and Clay (plastic)

3

CG L18-482

399 Lindbergh AveLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152

GRAIN SIZE ANALYSIS OF SOILS(ASTM D 422)

NV5 G18-131-11LNew Alignment North Manteca B-10

RC

0

7/9/2018

PARTICLE SIZE DISTRIBUTION

Cobbles

Gravel Sand

13.5-15

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.001

0.01

0.1

110100

Perc

ent P

assi

ng, %

Particle Size, mm3

-in #4

#10

#40

#200

60-min

0.005

0.074

0.425

2.00

4.76

76.2

HYDROMETER ANALYSISSIEVE ANALYSISU.S. STANDARD SERIESCLEAR SQUARE OPENINGS TIME READINGS


A S S O C I A T E S

GRAIN SIZE ANALYSIS OF SOILSASTM D422



D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L



Date Tested:

Coarse Medium Fine

- 0 19 75

Description of Soil: Poorly Graded Sand with Silt (SP-SM)

RC

0

7/9/2018


Cobbles

Gravel Sand

23.5'-25'


6

CG SPT#6




0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.001

0.01

0.1

110100

Perc

ent P

assi

ng, %

Particle Size, mm3

-in #4

#10

#40

#200

60-min

0.005

0.074

0.425

2.00

4.76

76.2



A S S O C I A T E S




D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L



Date Tested:

Coarse Medium Fine

- 2 59 37



2

CG SPT#5




RC

0

7/9/2018


Cobbles

Gravel Sand

18.5-20

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.001

0.01

0.1

110100

Perc

ent P

assi

ng, %

Particle Size, mm3

-in #4

#10

#40

#200

60-min

0.005

0.074

0.425

2.00

4.76

76.2



A S S O C I A T E S




D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L



Date Tested:

Coarse Medium Fine

- 1 52 45



2

RC

0

7/9/2018


Cobbles

Gravel Sand

9.5'CG L18-482




0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.001

0.01

0.1

110100

Perc

ent P

assi

ng, %

Particle Size, mm3

-in #4

#10

#40

#200

60-min

0.005

0.074

0.425

2.00

4.76

76.2



A S S O C I A T E S




D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L



Date Tested:

Coarse Medium Fine

- 1 48 48



3

CG SPT#5




RC

0

7/6/2018


Cobbles

Gravel Sand

18.5'-20'

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.001

0.01

0.1

110100

Perc

ent P

assi

ng, %

Particle Size, mm3

-in #4

#10

#40

#200

60-min

0.005

0.074

0.425

2.00

4.76

76.2



A S S O C I A T E S




D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L



Date Tested:

Coarse Medium Fine

- 1 48 48



3

CG SPT#5




RC

0

7/6/2018


Cobbles

Gravel Sand

18.5'-20'

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.001

0.01

0.1

110100

Perc

ent P

assi

ng, %

Particle Size, mm

3-in #4

#10

#40

#200

60-min

0.005

0.074

0.425

2.00

4.76

76.2


399 Lindbergh AveLivermore, CA 94551

Ph: (925) 315-3151Fax: (925) 315-3152

Sample Date: 6/21/2018Sample By: DT

Test Date: 7/9/2018Report Date: 7/10/2018

Tested By: RC

SPECIMEN A B CEXUDATION PRESSURE, LOAD (lb) 6896 4432 2570EXUDATION PRESSURE, PSI 549 353 205EXPANSION, * 0.0001 IN 0 0.0002 0.0001EXPANSION PRESSURE, PSF 0 0 0

Enter value of "T" from the Chart above STABILOMETER PH AT 2000 LBS 28 40 48DISPLACEMENT 4.17 4.73 4.23

74 61 5874 61 578.4 8.8 9.7

DRY DENSITY AT TEST, PCF 129.8 128.1 127.6

"R" VALUE BY EXPANSION

Remark:

59

N/APRESSURE TI = 4.0, GF=1.50

RESISTANCE VALUE "R"

% MOISTURE AT TEST

"R" VALUE AT 300 PSI EXUDATION PRESSURE

"R" VALUE CORRECTED FOR HEIGHT

R-Value Test

Caltrans Test Method 301

Sample Description: Dark Reddish Brown Silty Sand (SM)

New AlignmentG18-131-11L

L18-482B-11@1-5

Project Name:Project Number:

Lab Tracking ID:Sample Location:

Sample Source:

COVER THICKNESS BY EXPANSION PRESSURE, INCHES

"R" V

ALU

E

CO

VE

R T

HIC

KN

ES

S B

Y S

TAB

ILO

ME

TER

, IN

CH

ES

EXUDATION PRESSURE, PSI

0 2 4 6 8 10 12 14 16 18 20 22 24 26

100

90

80

70

60

50

40

30

20

10

0

0

2

4

6

8

10

12

14

16

18

20

22

2410020300400500600700800 0

Reviewed By: ____JKA_______


A S S O C I A T E S

R- VALUE TEST



D. Tower

C. Melo

SitePlan.indd

7/19/18

G18-131-11L


APPENDIX C

SUBSURFACE DATA FROM PREVIOUS INVESTIGATIONS

• BSK (2018), Geotechnical Investigation Report, North Manteca Trunk Sewer and Milo Candini

Drive Extension, 1215 West Center Street, Suite 201, Manteca, California, dated June 29, 2018

(File No. G16-127-11L)

• BSK (2016), Geotechnical Investigation Report, Manteca Water Quality Control Facility

Improvements, 2450 West Yosemite Avenue, Manteca, California, dated May 6, 2016 (File No.

G15-133-10L)

111

83

91114

479

101213

101518

6813

1A1B1C

2

3A3B3C

4

5A5B5C

3-3.5

3-3.5

3

5

37

GRAVEL : fillPOORLY GRADED SAND WITH SILT (SP-SM) : olive brown, slightly moist, fine grained sand (FILL)

POORLY GRADED SAND WITH SILT (SP-SM):olive to olive brown, moist, medium dense, fine to mediumgrained sand

pocket of well graded sand, fine to medium grained sand

POORLY GRADED SAND (SP): olive brown, moist, medium dense, fine to medium grainedsand

SANDY SILT (ML): olive to olive yellow, moist, firm, slight plasticity

POORLY GRADED SAND (SP): gray, moist, dense, fine to medium grained sand

SANDY LEAN CLAY (CL): olive brown, moist, firm, low to medium plasticity


Exploration Geoservices Inc., Mobile B-534-inch tricone, rotary wash140 lb4-inches30 inSurface Conditions: Gravel

51.57/29/157/29/152.5 inch inner diameter1.4 inch inner diameter



23 feetSurface El.:

Location: B-1

Pla

stic

Lim

it

Pla

stic

ity I

ndex

In-S

itu D

ry W

eigh

t(p

cf)

Pen

etra

tion

Blo

ws

/ F

oot

Dep

th, f

eet

5

10

15

20

25

30

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

enet

ro-

met

er,

TS

F

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

tent

(%)

Liqu

id L

imit


Manteca Water Quality Control FacilityG15-133-10LManteca, CaliforniaK. JohnstonC. Melo

BSK Associates324 Earhart WayLivermore, CA 94551Telephone: 925-315-3151Fax: 925-315-3152


Sam

ples

GE

O_T

AR

GE

T G

15-1

33-1

0L M

AN

TE

CA

WW

TP

.GP

J G

EO

TE

CH

NIC

AL

08.G

DT

1/6

/16

105

4513

263638

151928

172019

6912

6

7A7B7C

8

9A9B9C

10

2.5-3

50

20

SANDY LEAN CLAY (CL): olive brown, moist, firm, low to medium plasticity (continued)

POORLY GRADED SAND (SP):olive brown, moist, very dense, fine to medium grainedsand, mica specs

olive brown to olive, dense

olive yellow, medium dense

LEAN CLAY (CL):olive brown, moist, firm, low to medium plasticity

medium plasticity

Boring terminated at approximately 51.5 feet.Groundwater depth masked by rotary wash drilling method.Boring backfilled with cement grout.


Exploration Geoservices Inc., Mobile B-534-inch tricone, rotary wash140 lb4-inches30 inSurface Conditions: Gravel




23 feetSurface El.:

Location: B-1

Pla

stic

Lim

it

Pla

stic

ity I

ndex

In-S

itu D

ry W

eigh

t(p

cf)

Pen

etra

tion

Blo

ws

/ F

oot

Dep

th, f

eet

35

40

45

50

55

60

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

enet

ro-

met

er,

TS

F

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

tent

(%)

Liqu

id L

imit





Sam

ples

GE

O_T

AR

GE

T G

15-1

33-1

0L M

AN

TE

CA

WW

TP

.GP

J G

EO

TE

CH

NIC

AL

08.G

DT

1/6

/16

106

104

91011

333

334

5610

112034

1A1B1C

2A2B2C

3A3B3C

4A4B4C

5A5B5C

4115

4

20

GRAVEL:fillSILTY SAND (SM):olive to olive brown, slightly moist, fine grained sand, micaspecs, (FILL)SILTY SAND (SM):olive to olive brown, slightly moist, medium dense, finegrained sand, mica specs

loose

12:47 am

12:12 am

POORLY GRADED SAND (SP):gray to olive gray, wet, medium dense, fine to mediumgrained sand, some coarse grained sand

dense

Boring terminated at approximately 21.5 feet.Boring backfilled with cement grout.


Exploration Geoservices Inc., Mobile B-538.25-inch metal carbine combo, hollow stem auger140 lb8-inches30 inSurface Conditions: Gravel access road




25 feetSurface El.:

Location: B-3

Pla

stic

Lim

it

Pla

stic

ity I

ndex

In-S

itu D

ry W

eigh

t(p

cf)

Pen

etra

tion

Blo

ws

/ F

oot

Dep

th, f

eet

5

10

15

20

25

30

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

enet

ro-

met

er,

TS

F

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

tent

(%)

Liqu

id L

imit





Sam

ples

GE

O_T

AR

GE

T G

15-1

33-1

0L M

AN

TE

CA

WW

TP

.GP

J G

EO

TE

CH

NIC

AL

08.G

DT

1/6

/16

104

103

1088

446

467

4910

71717

1A1B1C

2A2B2C

3A3B3C

4A4B4C

5A5B5C 2.0-3.0

8

9

18

GRAVEL: fillPOORLY GRADED SAND WITH SILT (SP-SM)):olive to olive brown, slightly moist, fine grained sand, micaspecs (FILL)POORLY GRADED SAND WITH SILT (SP-SM):olive to olive brown, slightly moist, medium dense, finegrained sand, mica specs

loose

POORLY GRADED SAND (SP):gray to olive gray, moist, loose, fine to medium grained sand

11:49 am

11:34 am

wet, medium dense

LEAN CLAY (CL):light brownish gray, moist, firm, low to medium plasticity,mica specsBoring terminated at approximately 21.5 feet.Boring backfilled with cement grout.

Exploration Geoservices Inc., Mobile B-538.25-inch metal carbine combo, hollow stem auger140 lb8-inches30 inSurface Conditions: Gravel access road




25 feetSurface El.:

Location: B-4

Pla

stic

Lim

it

Pla

stic

ity I

ndex

In-S

itu D

ry W

eigh

t(p

cf)

Pen

etra

tion

Blo

ws

/ F

oot

Dep

th, f

eet

5

10

15

20

25

30

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

enet

ro-

met

er,

TS

F

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

tent

(%)

Liqu

id L

imit





Sam

ples


GE

O_T

AR

GE

T G

15-1

33-1

0L M

AN

TE

CA

WW

TP

.GP

J G

EO

TE

CH

NIC

AL

08.G

DT

5/1

1/16

700 22nd St

Bakersfield, CA

Ph: (661) 327-0671

Fax: (661) 324-4218

Project Name: Sample Date: 7/29/2015

Project Number: G15-133-10L Test Date: 8/10/2015

Sample Location: Lab Tracking ID: Report Date: 8/14/2015

Sample Description:

B15-269

V. Simental

K J Manteca WWTP Improvements

SP: Fine Sand; grey; moist

B-1 @ 36 bgs

Direct Shear TestASTM D-3080

Sampled By:

Tested By:

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4 5 6 7 8 9 10 11

SH

EA

R S

TR

ES

S (

KS

F)

NORMAL STRESS (KSF)

SHEAR STRENGTH DIAGRAM

DRY DENSITY: 105 pcf

MOISTURE CONTENT: 20%

INTERNAL FRICTION ANGLE, f = 40º

COHESION, c = 0.0 KSF

40 o

700 22nd St

Bakersfield, CA

Ph: (661) 327-0671

Fax: (661) 324-4218




Sample Description:

B15-269

J. Laybourn


B-4 @ 6 bgs

SP-SM: Poolry Graded Sand with Silt; brown; fine to medium; moist


Sampled By:

Tested By:

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4 5 6 7 8 9 10 11

SH

EA

R S

TR

ES

S (

KS

F)

NORMAL STRESS (KSF)



MOISTURE CONTENT: 9 %



30 o

700 22nd St

Bakersfield, CA

Ph: (661) 327-0671

Fax: (661) 324-4218




Sample Description:

B15-269

J. Laybourn


B-4 @ 16 bgs

SP: Fine Sand; grey; wet


Sampled By:

Tested By:

0

1

2

3

4

5

6

7

8

9

10

0 1 2 3 4 5 6 7 8 9 10 11

SH

EA

R S

TR

ES

S (

KS

F)

NORMAL STRESS (KSF)



MOISTURE CONTENT: 18 %



37 o

Client: Project No.:

Project: Boring Number:

Tested By: Sample ID:

Reviewed By: Sample Depth:

Date Tested:

Clay (Plastic)

Coarse Medium Fine

-

4 66 27 #N/A

Specific Gravity, Gs - 2.65


G. Minerales

#N/A

8/10/2015


Cobble

s

Gravel Sand Silt (non-plastic)

2

J. Auser 10'

324 Earhart Way

Livermore, CA 94551

Phone: (925) 315-3151

Fax: (925) 315-3152

GRAIN SIZE ANALYSIS OF SOILS

(ASTM D 422)

HERWIT Eng. G15-133-10L

Manteca WWTP B-1

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0

01

0.0

1

0.1

110

100

Perc

en

t P

assin

g,

%

Particle Size, mm

3 - in

#4

#1

0

#4

0

#2

00

60

-min

0

.00

5

0.0

74

0.4

25

2.0

0

4.7

6

76

.2

HYDROMETER ANALYSIS SIEVE ANALYSIS

U.S. STANDARD SERIES CLEAR SQUARE OPENINGS TIME READINGS

Client: Project No.:

Project: Boring Number:

Tested By: Sample ID:

Reviewed By: Sample Depth:

Date Tested:

Clay (Plastic)

Coarse Medium Fine

-

#N/A 13 45 6


Description of Soil: Silty Sand (SM)

10.5'

324 Earhart Way

Livermore, CA 94551

Phone: (925) 315-3151

Fax: (925) 315-3152

GRAIN SIZE ANALYSIS OF SOILS

(ASTM D 422)

G15 - 133 - 10L

B - 3

G. Minerales

J. Auser

HERWIT Eng.

Manteca WWTP

3B

#N/A 35

8/31/2015


Cobble

s


0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0

01

0.0

1

0.1

110

100

Perc

en

t P

assin

g,

%

Particle Size, mm

3 - in

#4

#1

0

#4

0

#2

00

60

-min

0

.00

5

0.0

74

0.4

25

2.0

0

4.7

6

76

.2

HYDROMETER ANALYSIS SIEVE ANALYSIS

U.S. STANDARD SERIES CLEAR SQUARE OPENINGS TIME READINGS

Job No.: Boring: Run By: MD

Client: Sample: Reduced: PJ

Project: Depth, ft.: Checked: PJ/DC

Soil Type: Date: 8/21/2015

Assumed Gs 2.75 Initial Final

36.8 27.6

82.7 97.6

1.075 0.760

94.2 100.0% Saturation:

Dry Density, pcf:

Moisture %:

B-1

26Maneca WWTP - G15-133-10L

BSK Associates

664-048

Grayish Brown SILT w/ Sand (slightly plastic)

Void Ratio:

0.0

5.0

10.0

15.0

20.0

25.0

10 100 1000 10000 100000

Str

ain

, %

Effective Stress, psf

Strain-Log-P Curve

Consolidation Test ASTM D2435

Remarks:

Job No.: Date: 08/13/15 3.9%

Client: Tested MD

Project: Reduced RU

Sample Checked DC

Soil Type:

A B C D

800 263 151

1200 1200 1200

61 81 91

3086 3146 3099

2092 2099 2114

2.41 2.52 2.43

9.2 10.9 11.8

114.4 113.4 109.8

0.0 0.0 0.0

26 28 33

4.26 4.46 4.5

74 73 67

Turns Displacement

Dark Brown Silty SAND

Weight of Mold, grams

Exudation Pressure, psi

Initial Moisture, 664-048

BSK Associates

Manteca WWTP - G15-133-10L

Moisture Content, %

Specimen Number

Prepared Weight, grams

Final Water Added, grams/cc

Weight of Soil & Mold, grams

Height After Compaction, in.

psfExpansion

Pressure

R-value by

Stabilometer73

0

Remarks:

B-2/B-4 @ 0-2'

Dry Density, pcf

R-value

Stabilometer @ 2000

Expansion Pressure, psf

Stabilometer @ 1000

0

100

200

300

400

500

600

700

800

900

1000

0

10

20

30

40

50

60

70

80

90

100

0 100 200 300 400 500 600 700 800

Ex

pa

ns

ion

Pre

ss

ure

, p

sf

R-v

alu

e

Exudation Pressure, psi

R-value

Expansion Pressure,psf

R-value Test Report (Caltrans 301)

113

98

1A1B1C

2A2B2C

3

4A4B4C

5

9

4

5

24

ASPHALT: approximately 3 to 4 inches of asphaltPOORLY GRADED GRAVEL WITH SAND (GP):approximately 12 inches thick, possibly aggregate base

POORLY GRADED SAND WITH SILT (SP-SM): yellowishbrown, moist, dense, fine to medium grained sand

decreased silt content with depth

dark brown mottled with yellowish brown, loose

POORLY GRADED SAND (SP): brown, moist to wet,dense, fine to medium grained sand

12:52 pm, 10/3/16

SILTY SAND (SM): brown, very moist, dense, fine grainedsandDirect Shear: Ø=34º, C=800 psf, (See site plate B-1)

POORLY GRADED SAND (SP): brown, moist, very dense,fine to medium grained sand, rock fragments

1:45 pm, 10/3/16

142526

141925

336

101430

163850/3.5"


Exploration GeoServices Mobile B-53Hollow Stem140 lbs8-in30-in




24 ft.Surface El.:

Location:

Pla

stic

Lim

it

Pla

stic

ity I

ndex

In-S

itu D

ry W

eigh

t(p

cf)

Dep

th, f

eet

5

10

15

20

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

enet

ro-

met

er,

TS

F

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

tent

(%)

Liqu

id L

imit


North Manteca Trunk SewerG16-127-11LManteca, CAD. TowerM. McNally


Sam

ples

Pen

etra

tion

Blo

ws

/ 6

inch

es

BSK Associates324 Earhart WayLivermore, CA 94551Telephone: (925)-315-3151Fax: (925)-315-3152

GE

O_T

AR

GE

T B

OR

ING

LO

GS

.GP

J G

EO

TE

CH

NIC

AL

08.G

DT

11/

9/1

6

6

7

8A8B8C

9

POORLY GRADED SAND WITH SILT (SP-SM): brown,wet, medium dense, fine to coarse grained sand

SANDY LEAN CLAY (CL): light brownish gray, wet, firm,fine grained sandPOORLY GRADED SAND WITH SILT (SP-SM): brown,wet, medium dense, fine to coarse grained sand

SANDY FAT CLAY (CH): dark brownish gray, moist to wet,firm, medium to high plasticity, fine to coarse grained sand

CLAYEY SAND (SC): light brownish gray, wet, loose tomedium dense, fine to medium grained sand, iron oxidestaining

POORLY GRADED SAND (SP): multicolored, wet,medium dense, fine to coarse grained sand

Boring terminated at approximately 40 feet. Freegroundwater first observed at approximately 12.5 feet andthen remeasured at approximately 21.5 feet. Boring wasbackfilled with cement grout and patched with approximately6 inches of Quickrete.

10911

101522

3510

4919






24 ft.Surface El.:

Location:

Pla

stic

Lim

it

Pla

stic

ity I

ndex

In-S

itu D

ry W

eigh

t(p

cf)

Dep

th, f

eet

25

30

35

40

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

enet

ro-

met

er,

TS

F

% P

assi

ngN

o. 2

00 S

ieve

In-S

ituM

oist

ure

Con

tent

(%)

Liqu

id L

imit




Sam

ples

Pen

etra

tion

Blo

ws

/ 6

inch

es


GE

O_T

AR

GE

T B

OR

ING

LO

GS

.GP

J G

EO

TE

CH

NIC

AL

08.G

DT

11/

9/1

6

104

1A1B1C

2A2B2C

3

4A4B4C

5

1.0-4.0

9

17

SILTY SAND (SM): brown, moist, non-plastic, fine tomedium grained sand

porous, medium dense

increased silt content with depth

POORLY GRADED SAND WITH SILT (SP-SM): brown,moist, loose, fine to medium grained sand, slightly porous

SILTY LEAN CLAY (CL): light brownish gray, moist, low tomedium plasticity, firm to hard, iron oxide staining, increasedsand content with depth

SILTY SAND (SM): light brownish gray, moist, dense, finegrained sand, iron oxide staining

SILTY SAND WITH CLAY (SM): light brownish gray,moist, medium dense, medium plasticity

approximately 2- to 3-inch of well graded sand seam, moistto wet

81012

456

346

142036

5510






23 ft.Surface El.:

Location:

Pla

stic

Lim

it

Pla

stic

ity I

ndex

In-S

itu D

ry W

eigh

t(p

cf)

Dep

th, f

eet

5

10

15

20

Gra

phic

Log

Sam

ple

Num

ber

Poc

ket P

enet

ro-

met

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TS

F

% P

assi

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Con

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(%)

Liqu

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Sam

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Pen

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GE

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08.G

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11/

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108

6A6B6C

7

8A8B8C

9

17

POORLY GRADED SAND (SP): gray, moist to wet, verydense, fine to medium grained sand

Direct Shear: Ø =40°, C=0 psf, (See plate B-4)

dense, fine to coarse grained sand

9:30 am, 10/3/16

SANDY LEAN CLAY (CL): gray, moist, firm to hard,medium to high plasticity

POORLY GRADED SAND (SP): gray, wet, dense, fine tocoarsed grained sand

brown, increased clay content with depth

Boring terminated at approximately 40 feet. Freegroundwater observed at approximately 30 feet. Boringbackfilled with cement grout.

182050

71630

244450/4"

141828






23 ft.Surface El.:

Location:

Pla

stic

Lim

it

Pla

stic

ity I

ndex

In-S

itu D

ry W

eigh

t(p

cf)

Dep

th, f

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30

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(%)

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11/

9/1

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108

93

1A1B1C

2A2B2C

3

4A4B4C

5 9

14

3

SILTY SAND (SM): brown, moist, medium dense, finegrained sand, porous

decreased silt content with depth, fine to medium grainedsandDirect Shear: Ø =39º, C=500 psf, (see plate B-5)

POORLY GRADED SAND WITH SILT (SP-SM): lightbrownish gray to multicolored, moist, loose, fine to mediumgrained sand

POORLY GRADED SAND (SP): light brownish graymottled with yellow to multicolored, moist, medium dense,fine to coarse grained sand

POORLY GRADED SAND WITH SILT (SP-SM): brown,moist, medium dense, fine to medium grained sand,increased silt content with depth

779

7914

455

111618

121220






22 ft.Surface El.:

Location:

Pla

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Lim

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Pla

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ity I

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In-S

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t(p

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Dep

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7

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POORLY GRADED SAND (SP): light brownish graymottled with yellow to multicolored, moist, very dense, fineto coarse grained sand11:10 am, 10/3/16

wet, fine to coarse grained sand

medium dense, fine to medium grained sand

Boring terminated at approximately 40 feet. Freegroundwater observed at approximately 23 feet. Boringbackfilled with cement grout.

124050/2"

182838

50/4"

7914






22 ft.Surface El.:

Location:

Pla

stic

Lim

it

Pla

stic

ity I

ndex

In-S

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t(p

cf)

Dep

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Depth (ft): 14.5 14.5 14.5

Normal Load (psf) 1000 3000 5000Dry Mass of Specimen (g) 119.3 120.1 121.3Initial Height (in) 1.00 1.04 1.03Initial Diameter (in) 2.40 2.41 2.42Initial Void Ratio 0.683 0.737 0.721Initial Moisture (%) 24.4 24.0 24.9Initial Wet Density (pcf) 124.6 120.4 122.3Initial Dry Density (pcf) 100.1 97.1 97.9Initial Saturation (%) 96.3 88.1 93.2ΔHeight Consol (in) 0.0085 0.0186 0.0254At Test Void Ratio 0.669 0.706 0.679At Test Moisture (%) 24.0 24.5 24.9At Test Wet Density (pcf) 125.4 123.2 125.5At Test Dry Density (pcf) 101.1 98.9 100.5At Test Saturation (%) 97.0 93.9 98.9Strain Rate (%/min) 1.0 1.1 0.9Strengths Picked at 5% 5% 5%Shear Stress (psf) 1385 3139 4112ΔHeight (in) at 5%Ultimate Stress (psf)

©

800

Specimen Data



Brown SiltySAND

Visual Description:

Brown SiltySAND

Brown SiltySAND

Remarks:


BSK AssociatesN.Manteca Sewer Trunk

664-092 G16-127-11L10/27/2016

0

500

1000

1500

2000

2500

3000

3500

4000

4500

0.0 5.0 10.0 15.0 20.0 25.0Sh

ear S

tres

s (p

sf)

Deformation (%)

Shear Stress vs. Deformation

Sample 1

Sample 2

Sample 3

0

2000

4000

6000

8000

0 2000 4000 6000 8000

Shea

r Str

ess,

psf

Normal Load, psf


0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.20000.0 5.0 10.0 15.0 20.0 25.0

Del

ta h

(in)

Deformation (%)

Change in Height

Sample 1

Sample 2

Sample 3


A S S O C I A T E S

DIRECT SHEAR RESULTS

B-1North Manteca Trunk Sewer

Manteca, California

D. Tower

10/31/16

G16-127-11L

C. Melo

SitePlan.indd


A S S O C I A T E S



Phi (deg) Ult. Phi (deg)1 2 3 4


Depth (ft): 24.5 24.5 24.5


©


BSK AssociatesN. Manteca Sewer Trunk

664-092 G16-127-11L11/1/2016


Gray Poorly Graded Sand

Visual Description:



Remarks:

Specimen Data


0

1000

2000

3000

4000

5000

6000

7000

8000

0.0 5.0 10.0 15.0 20.0 25.0

Shea

r Str

ess

(psf

)

Deformation (%)


Sample 1

Sample 2

Sample 3

0

2000

4000

6000

8000

0 2000 4000 6000 8000

Shea

r Str

ess,

psf

Normal Load, psf


0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.20000.0 5.0 10.0 15.0 20.0 25.0

Del

ta h

(in)

Deformation (%)

Change in Height

Sample 1

Sample 2

Sample 3



Manteca, California

D. Tower

11/1/16

G16-127-11L

C. Melo

SitePlan.indd

Ø>40º, Assume Ø=40º, C=0 psf

See NoteSee Note


A S S O C I A T E S





Depth (ft): 6.0 6.0 6.0


©


BSK AssociatesN. Manteca Sewer Trunk

664-092 G16-127-11L11/1/2016


Brown Silty Sand

Visual Description:

Brown Silty Sand

Brown Silty Sand

Remarks:

500

Specimen Data


0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0.0 5.0 10.0 15.0 20.0 25.0

Shea

r Str

ess

(psf

)

Deformation (%)


Sample 1

Sample 2

Sample 3

0

2000

4000

6000

8000

0 2000 4000 6000 8000

Shea

r Str

ess,

psf

Normal Load, psf


0.0000

0.2000

0.4000

0.6000

0.8000

1.0000

1.20000.0 5.0 10.0 15.0 20.0 25.0

Del

ta h

(in)

Deformation (%)

Change in Height

Sample 1

Sample 2

Sample 3



Manteca, California

D. Tower

11/1/16

G16-127-11L

C. Melo

SitePlan.indd



Date Tested:

Clay (Plastic)

Coarse Medium Fine

- 3 51 42 #N/A



GAM / RAK SPT #05

324 Earhart WayLivermore, CA 94551Phone: (925) 315-3151Fax: (925) 315-3152


G16 - 127 - 11LNorth Manteca Trunk Sewer B - 3

#N/A

11/4/2016

PARTICLE SIZE DISTRIBUTIONC

obbles


18.5' - 20.0'

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.001

0.01

0.1

110100

Perc

ent P

assi

ng, %

Particle Size, mm

3 -in #4

#10

#40

#200

60-min

0.005

0.074

0.425

2.00

4.76

76.2



A S S O C I A T E S

SIEVE ANALYSIS


Manteca, California

D. Tower

10/31/16

G16-127-11L

C. Melo

SitePlan.indd



Date Tested:

Clay (Plastic)

Coarse Medium Fine

- 0 39 52 #N/A



#N/A

11/4/2016


obbles


8.5' - 10.0'GAM / RAK SPT #03



NV5 G16 - 127 - 11LNorth Manteca Trunk Sewer B - 7

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.001

0.01

0.1

110100

Perc

ent P

assi

ng, %

Particle Size, mm3 -in #4

#10

#40

#200

60-min

0.005

0.074

0.425

2.00

4.76

76.2



A S S O C I A T E S

SIEVE ANALYSIS


Manteca, California

D. Tower

10/31/16

G16-127-11L

C. Melo

SitePlan.indd



Date Tested:

Clay (Plastic)

Coarse Medium Fine

- 2 23 67 #N/A



GAM / RAK SPT #05



NV5 G16 - 127 - 11LNorth Manteca Trunk Sewer B - 8

#N/A

11/4/2016


obbles


18.5' - 20.0'

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.001

0.01

0.1

110100

Perc

ent P

assi

ng, %

Particle Size, mm3 -in #4

#10

#40

#200

60-min

0.005

0.074

0.425

2.00

4.76

76.2



A S S O C I A T E S

SIEVE ANALYSIS


Manteca, California

D. Tower

10/31/16

G16-127-11L

C. Melo

SitePlan.indd


APPENDIX D

SUMMARY OF COMPACTION RECOMMENDATIONS

Area Compaction Recommendations (See Notes 1, 2, 3, 4)

Subgrade Preparation and Placement of General Engineered Fill, Including Imported Fill

Compact upper 12 inches of subgrade and entire depth of fill to a minimum of 90 percent compaction at near optimum moisture content for granular soils and to a minimum of 90 percent compaction at a minimum of 2 percent over optimum moisture content for clayey soils.

Trenches and Excavations5, 6 Compact trench backfill to a minimum of 90 percent compaction at near optimum moisture content for granular soils and to a minimum of 90 percent compaction at a minimum of 2 percent over optimum moisture content for clayey soils. Proper granular bedding and shading should be used beneath and around new utilities. Where trenches will be under pavements, the upper 12 inches should be compacted as recommended below.

Pavements Compact upper 12 inches of subgrade to at least 95 percent

compaction at near optimum moisture content for granular soils and to at least 93 percent compaction at least 2 percent over optimum moisture content for clayey soils. Compact aggregate base to at least 95 percent compaction at near optimum moisture content.

Notes:

(1) Depths are below finished subgrade elevation. (2) All compaction requirements refer to relative compaction as a percentage of the laboratory standard

described by ASTM D 1557.

(3) Fill material should be compacted in lifts not exceeding 8 inches in loose thickness.

(4) All subgrades should be firm and stable.

(5) In landscaping areas only, the percent compaction in excavations may be reduced to 85 percent.

(6) Where backfills are greater than 7 feet in depth below finish grade, the portion below a depth of 7 feet should be compacted to a minimum of 95 percent compaction where new or existing surface improvements are located within a 1H:1V projection line extending up from the bottom of trench excavations.

Documents

GEOTECHNICAL INVESTIGATION REPORT NEW ALIGNMENT FOR … · Senior Staff Engineer Senior Geotechnical Engineer Cristiano Melo, PE, GE #2756 ... 2018 draft report for this project