rfb_13242_info_only_geotechnical_investigation.pdf

GEOTECHNICAL INVESTIGATION

JAMACHA FORCE MAIN AND GRAVITY MAIN IMPROVEMENTS

(LA PRESA PHASE I)

Spring Valley, California

PREPARED FOR:

Ms. Rika Evans, PE Black & Veatch 300 Rancheros Drive, Suite 250 San Marcos, CA 92069

PREPARED BY:

Atlas Technical Consultants LLC 6280 Riverdale Street San Diego, CA 92120 February 4, 2021

6280 Riverdale Street San Diego, CA 92120

(877) 215-4321 | oneatlas.com

February 4, 2021

Atlas No. 200193P5 Report No. 1R

MS. RIKA EVANS, PE

BLACK & VEATCH

300 RANCHEROS DRIVE, SUITE 250

SAN MARCOS, CALIFORNIA 92069

Subject: Geotechnical Investigation Jamacha Force Main and Gravity Main Improvements Jamacha Boulevard, Spring Valley, California

Dear Ms. Evans:

Atlas Technical Consultants LLC (formerly SCST) is pleased to present this report describing the geotechnical investigation performed for the subject project. We conducted the investigation in general conformance with the scope of work presented in our proposal dated May 15, 2020.

Based on the results of our investigation, we consider the planned development feasible from a geotechnical standpoint, provided the recommendations of this report are followed.

If you have any questions, please call us at (619) 280-4321.

Respectfully submitted, Gillian L. Carzzarella, PE C87787 Andrew K. Neuhaus, CEG 2591 Project Engineer Chief Geologist

GLC:AKN:ds

Distribution: Ms. Rika Evans at EvansR@bv.com

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CONTENTS

1. INTRODUCTION

2. SCOPE OF WORK

2.1 Geotechnical Field Investigation

2.2 Laboratory Testing

2.3 Analysis and Report Preparation

3. SITE AND PROJECT DESCRIPTION

4. GEOLOGY AND SUBSURFACE CONDITIONS

5. GEOLOGIC HAZARDS

5.1 Faulting-Rupture Hazard

5.2 Liquefaction and Dynamic Settlement

5.3 Tsunamis, Seiches, and Flooding

5.4 Landslides and Slope Stability

5.5 Subsidence

5.6 Hydro-Consolidation

6. CONCLUSIONS

7. RECOMMENDATIONS

7.1 Earthwork

7.1.1 Site Preparation

7.1.2 Excavation Characteristics

7.1.3 Temporary Excavations

7.1.4 Temporary Shoring

7.1.5 Groundwater Seepage

7.1.6 Imported Soil

7.1.7 Oversized Material

7.2 Pipelines

7.2.1 Modulus of Soil Reaction

7.2.2 Pipe Bedding

7.2.3 Trench Backfill

7.2.4 Pipeline Settlement

7.2.5 Trench Resurfacing

7.2.6 Thrust Blocks

7.3 Soil Corrosivity

8. GEOTECHNICAL ENGINEERING DURING CONSTRUCTION

9. CLOSURE

10. REFERENCES

FIGURES

Figure 1 – Site Vicinity Map Figures 2A through 2D – Subsurface Exploration Maps Figure 3 – Regional Geology Map

APPENDICES

Field Investigation Laboratory Testing

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1. INTRODUCTION

This report presents the results of the geotechnical investigation Atlas performed for the subject project. The purpose of our work is to provide preliminary conclusions and recommendations regarding the geotechnical aspects of the project. Figure 1 presents a site vicinity map.

2. SCOPE OF WORK

We conducted this investigation in general conformance with the scope of work presented in our Proposal No. 20-0128R dated May 15, 2020. Our scope of work consisted of the following.

2.1 Geotechnical Field Investigation

Atlas performed a geologic reconnaissance to address potential geologic hazards and geotechnical conditions that could impact the proposed construction. We reviewed pertinent documents including published maps, project plans, and available geotechnical reports by others.

Prior to drilling, an Atlas representative visited the site to observe existing conditions and mark the proposed boring locations for underground utility clearance. Atlas notified Underground Service Alert (USA), as required by law, prior to the commencement of field activities. Additionally, our in-house private utility locator was used to mark utilities and clear the proposed boring locations.

Our field investigation was performed on October 21, 2020 and October 22, 2020 and consisted of advancing a total of six borings to depths between about 3 and 20 feet below the existing ground surface using a truck-mounted drill rig equipped with a hollow stem auger and hand tools.

The boring locations were selected by Black & Veatch. Figure 2 shows the approximate locations and depths of the borings. Two Atlas geologists logged the borings and collected samples of the materials encountered for geotechnical laboratory testing. Logs of the borings are presented in Appendix I. Soils were classified according to the Unified Soil Classification System (USCS).

2.2 Laboratory Testing

We tested selected samples to evaluate soil classification and engineering properties and develop geotechnical conclusions and recommendations. The laboratory tests consisted of in situ moisture and density, particle-size distribution, Atterberg limits, and corrosivity. The results of the laboratory tests and brief explanations of the test procedures are presented in Appendix II.

2.3 Analysis and Report Preparation

The results of the field and laboratory tests were evaluated to develop conclusions and recommendations regarding:

Subsurface conditions along the project alignment

Potential geologic hazards

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Site preparation

Excavation characteristics of the subsurface materials encountered

Support for the pipelines

Appropriate types of bedding and backfill materials as well as placement and compaction procedures

Suitability of excavated materials for use as bedding and backfill

Soil modulus E’ for pipeline design

Corrosivity

3. SITE AND PROJECT DESCRIPTION

The project is located within a suburban, developed area in the Spring Valley area in San Diego County, California. Based on our review of the provided project plans (Black & Veatch, 2020), we understand the subject project includes the installation of approximately 4900 linear feet (LF) of new sewer mains located along Jamacha Boulevard. The proposed sewer mains consist of approximately 400 LF of an 18-inch, PVC gravity main between Sacramento Avenue and Grand Avenue and approximately 4500 LF of 16-inch, PVC dual force mains between Grand Avenue and the existing Jamacha Pump Station. The existing 12-inch force main will be abandoned as part of this project. Additional improvements include the construction of new manholes, street resurfacing, and replacement of traffic loop detectors.

4. GEOLOGY AND SUBSURFACE CONDITIONS

Based on published geologic maps (Todd, 2004), and depending on location, the alignment is underlain by fill, quaternary young alluvium, very old paralic deposits (formerly known as Lindavista Formation), Mission Valley Formation, and Santiago Peak Volcanics. Materials encountered in our borings were consistent with the mapped geologic units. Descriptions of the materials encountered in the field investigation are presented below. Figure 3 presents a regional geology map.

Fill (Qf): Fill was encountered beneath the pavement sections in borings B-1 through B-4 and boring B-6 to a depth up to about 6½ feet below the existing ground surface. The fill consisted of medium dense to very dense clayey sand, clayey sand with gravel, silty gravel with sand, and soft to stiff sandy fat clay and sandy lean clay.

Quaternary Young Alluvium (Qya): Quaternary young alluvium was encountered beneath the fill in boring B-6 and extended to a depth of about 12½ feet below existing ground surface. The alluvium consisted of stiff sandy silt and lean clay and loose poorly graded sand. Interbedded layers of clayey sand and sandy lean clay were also encountered.

Very Old Paralic Deposits (Qvop): Very old paralic deposits were encountered beneath the pavement section in boring B-5 and beneath the alluvium in boring B-6; and extended

Page | 3 to the total depths explored of about 20 feet. As encountered, the very old paralic deposits consisted of moderately to strongly cemented sandy siltstone, silty sandstone, and cobble conglomerate with a clayey sand matrix; and well indurated sandy claystone with varying amounts of gravel.

Mission Valley Formation (Tmv): Mission Valley Formation was encountered beneath the fill in borings B-2 and B-3 and extended up to the total depths explored of about 16½ feet below existing ground surface. As encountered, the Mission Valley Formation consisted of moderately to strongly cemented silty and clayey sandstone and well indurated claystone.

Santiago Peak Volcanics (Ksp): Santiago Peak Volcanics were encountered below the Mission Valley Formation in boring B-2 and extended to the total depth explored of about 15½ feet below existing ground surface. The Santiago Peak Volcanics, as encountered, were weathered and broke down to very dense silty sand.

Groundwater: Groundwater was not encountered in the borings. Three wells located on Jamacha Boulevard near the intersection of Grand Avenue measured groundwater to be as shallow as 16½ feet in November 2013 (Geotracker, 2020). Accordingly, the groundwater table is expected to be below a depth that will influence the planned construction. However, groundwater levels may fluctuate due to rainfall, irrigation, broken pipes, or changes in site drainage. Because groundwater rise or seepage is difficult to predict, such conditions are typically mitigated if and when they occur.

5. GEOLOGIC HAZARDS

The site is not located within an area previously known for significant geologic hazards. Evidence of active faulting, liquefiable soils, or collapsible soils was also not observed during our investigation. A discussion of existing and potential geologic hazards follows.

5.1 Faulting-Rupture Hazard

The closest known active fault is the La Nacion fault zone located about 3½ miles west of the site (California Department of Conservation, 2020). The site is not located in an Alquist-Priolo Earthquake Fault Zone. No active faults are known to underlie or project toward the site.

Therefore, the probability of fault rupture at the site is low.

5.2 Liquefaction and Dynamic Settlement

Liquefaction occurs when loose, saturated sands and silts are subjected to strong ground shaking.

The soils lose shear strength and become liquid, resulting in large total and differential ground surface settlements, and possible lateral spreading during an earthquake. Given the dense nature of the materials beneath the site, we consider the potential for liquefaction and dynamic settlement to occur to be low.

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5.3 Tsunamis, Seiches, and Flooding

The site is not located within an area affected by tsunami inundation (Cal EMA, 2009), therefore, damage due to tsunamis is considered negligible. Seiches are periodic oscillations in large bodies of water such as lakes, harbors, bays, or reservoirs. The eastern portion of the project alignment is located about ¼ mile north of the Sweetwater Reservoir, however, the elevation at this portion of the alignment is about 40 feet higher than Sweetwater Reservoir. Therefore, the potential for a seiche to affect the site is considered low. According to the Flood Insurance Rate Map (FIRM), the site is located within an area designated as Zone X (FEMA, 2012). Zone X is an area outside the 0.2% annual chance flood.

5.4 Landslides and Slope Stability

Evidence of landslides or slope instabilities was not observed during our investigation. The potential for landslides or slope instabilities to occur at the site is considered low.

5.5 Subsidence

The site is not located in an area of known subsidence associated with fluid withdrawal (groundwater or petroleum); therefore, the potential for subsidence due to the extraction of fluids is considered low.

5.6 Hydro-Consolidation

Hydro-consolidation can occur in recently deposited sediments (less than 10,000 years old) that were deposited in a semi-arid environment. Examples of such sediments are aeolian sands, alluvial fan deposits, and mudflow sediments deposited during flash floods. The pore spaces between the particle grains can re-adjust when inundated by groundwater causing the material to consolidate. The relatively dense formational materials underlying the site are not considered susceptible to hydro-consolidation. Due to the absence of groundwater, the alluvium is considered susceptible to hydro-consolidation; however, the risk to the pipeline should be negligible.

6. CONCLUSIONS

Based on our investigation, we consider cut and cover pipeline construction to be feasible from a geotechnical standpoint, provided the recommendations of this report are followed. There are no geologic hazards of sufficient magnitude that preclude the intended improvements. The main geotechnical consideration affecting the project is potentially difficult excavations in well indurated and strongly cemented very old paralic deposits, Mission Valley Formation, and Santiago Peak Volcanics. The materials anticipated below the pipeline depths are expected to generally provide good pipeline support. The recommendations presented herein may need to be updated once final plans are developed.

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7. RECOMMENDATIONS

The remainder of this report presents recommendations regarding earthwork construction as well as geotechnical recommendations for the design of the proposed structure and improvements.

These recommendations are based on empirical and analytical methods typical of the standard of practice in southern California. If these recommendations appear not to address a specific feature of the project, please contact our office for additions or revisions to the recommendations.

7.1 Earthwork

Earthwork is anticipated to include site preparation, excavations for underground utilities, and placement and compaction of backfill. Grading and earthwork should be conducted in accordance with the CBC and with the recommendations of this report. The following recommendations are provided regarding specific aspects of the proposed earthwork construction. These recommendations should be considered subject to revision based on field conditions observed by the geotechnical consultant during grading.

7.1.1 Site Preparation

Site preparation should begin with the removal of existing improvements, vegetation, and debris.

Subsurface improvements that are abandoned should be removed, and the resulting excavations should be backfilled and compacted in accordance with the recommendations of this report.

Pipeline abandonment can consist of capping or rerouting at the project perimeter and removal within the project perimeter. If appropriate, abandoned pipelines can be filled with grout or slurry as recommended by and observed by the geotechnical consultant.

7.1.2 Excavation Characteristics

It is anticipated that excavations can be achieved with conventional earthwork equipment in good working order. Difficult excavation should be anticipated in cemented/indurated zones within the very old paralic deposits, Mission Valley Formation, and Santiago Peak Volcanics. Gravel and cobbles should also be anticipated within fill, alluvium, very old paralic deposits, and Mission Valley Formation. The contractor should mobilize equipment capable of excavating well indurated and strongly cemented materials with gravel and cobbles.

7.1.3 Temporary Excavations

Temporary excavations 3 feet deep or less can be made vertically. Deeper temporary excavations in fill and alluvium should be laid back no steeper than 1½:1 (horizontal:vertical) per Cal/OSHA Type C soil classification; and in the very old paralic deposits, Mission Valley Formation, and Santiago Peak Volcanics, should not be steeper than 1:1 (horizontal:vertical) per Cal/OSHA Type B soil classification. The faces of temporary slopes should be inspected daily by the contractor’s Competent Person before personnel are allowed to enter the excavation. Zones of potential instability, sloughing, or raveling should be brought to the attention of the engineer and corrective action implemented before personnel begin working in the trench.

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Slopes steeper than those described above will require shoring. Soldier piles and lagging, corrugated metal pipe, internally braced shoring, or trench boxes could be used. If trench boxes or corrugated metal pipe are used, the soil immediately adjacent to the shoring is not directly supported. Ground surface deformations immediately adjacent to the pit or trench could be greater where trench boxes are used compared to other methods of shoring.

Excavated soils should not be stockpiled behind temporary excavations within a distance equal to the depth of the excavation. Atlas should be notified if other surcharge loads are anticipated so that lateral load criteria can be developed for the specific situation. If temporary slopes are to be maintained during the rainy season, berms are recommended along the tops of slopes to prevent runoff water from entering the excavation and eroding the slope faces.

7.1.4 Temporary Shoring

For design of cantilevered shoring, an active soil pressure equal to a fluid weighing 40 pounds per cubic feet (pcf) can be used for level retained ground or 60 pcf for 2:1 (horizontal:vertical) sloping ground. The surcharge loads on shoring from traffic and construction equipment adjacent to the excavation can be modeled by assuming an additional 2 feet of soil behind the shoring. For design of soldier piles, an allowable passive pressure of 300 pounds per square foot (psf) per foot of embedment over twice the pile diameter up to a maximum of 3,500 psf can be used. Soldier piles should be spaced at least three pile diameters, center to center. Continuous lagging will be required throughout. The soldier piles should be designed for the full anticipated lateral pressure;

however, the pressure on the lagging will be less due to arching in the soils. For design of lagging, the earth pressure can be limited to a maximum value of 400 psf.

Piles should be filled with concrete immediately after drilling. The concrete should be pumped to the bottom of the drilled holes using the tremie method. If casing is used, the casing should be removed as the concrete is placed, keeping the level of the concrete at least 5 feet above the bottom of the casing at all times.

7.1.5 Groundwater Seepage

Groundwater seepage may occur locally and should be anticipated in excavations. An experienced and qualified specialty or dewatering contractor should design the dewatering system. Atlas should review the design.

7.1.6 Imported Soil

Imported soil should consist of predominately granular soil free of organic matter and rocks greater than 6 inches. Imported soil should be observed and, if appropriate, tested by Atlas prior to transport to the site to assess suitability for the intended use.

7.1.7 Oversized Material

Excavations may generate oversized material. Oversized material is defined as rocks or cemented clasts greater than 6 inches in largest dimension. Oversized material should be broken

Page | 7 down to no greater than 6 inches in largest dimension for use in fill, used as landscape material, or disposed of off site.

7.2 Pipelines

7.2.1 Modulus of Soil Reaction

The modulus of soil reaction (E’) is used to characterize the stiffness of soil backfill placed along the side of buried flexible pipelines for evaluating deflection due to the load of associated with trench backfill over the pipe. A value of 1,400 psi is recommended for the modulus of soil reaction assuming that granular bedding material is placed adjacent to the pipe and is compacted to a minimum of 90% relative compaction.

7.2.2 Pipe Bedding

Pipe bedding as specified in the “Greenbook” Standard Specifications for Public Works Construction can be used. Bedding material should consist of clean sand having a sand equivalent not less than 20 and should extend to at least 12 inches above the top of pipe.

Alternative materials meeting the intent of the bedding specifications are also acceptable.

Samples of materials proposed for use as bedding should be provided to the engineer for inspection and testing before the material is imported for use on the project. The on-site materials are not expected to meet “Greenbook” bedding specifications (i.e. clean sand) and cannot be processed to meet the requirements as the material types cannot be changed. The pipe bedding material should be placed over the full width of the trench. After placement of the pipe, the bedding should be brought up uniformly on both sides of the pipe to reduce the potential for unbalanced loads. No voids or uncompacted areas should be left beneath the pipe haunches. Ponding or jetting the pipe bedding should not be allowed.

Where pipeline inclinations exceed 15 percent, cutoff walls are recommended in trench excavations. Additionally, we do not recommend that open graded rock be used for pipe bedding or backfill because of the potential for piping erosion. The recommended bedding is clean sand having a sand equivalent not less than 20 or 2-sack sand/cement slurry. If sand/cement slurry is used for pipe bedding to at least 1 foot over the top of the pipe, cutoff walls are not considered necessary. The need for cutoff walls should be further evaluated by the project civil engineer designing the pipeline.

7.2.3 Trench Backfill

Utility trench sections should conform to the minimum requirements of the County of San Diego.

In our opinion, the excavated on-site material, except for soil containing roots, debris, and rock greater than 6 inches, can be used as trench backfill provided it meets the recommendations for fill material. However, in our opinion, the on-site material will not meet the most recent edition of the Greenbook (2018), which states that trench backfill material should have a sand equivalent (SE) greater than 20.

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Backfill should be placed in 6-inch to 8-inch thick loose lifts, moisture conditioned to near optimum moisture content, and compacted to at least 90% relative compaction of the material’s maximum dry density. Where fill is to be placed on surfaces inclined steeper than 5:1 (horizontal: vertical), benches should be excavated to provide a relatively level surface for fill placement. Benches should extend through any loose soils to expose competent material.

The top 12 inches of trench backfill beneath paved areas should be moisture conditioned to near optimum moisture content and compacted to at least 95% relative compaction of the material’s maximum dry density. Aggregate base material should be compacted to at least 95% relative compaction. Materials and methods of construction should conform to good engineering practices and the County of San Diego Design Standards.

The maximum dry density and optimum moisture content for the evaluation of relative compaction should be determined in accordance with ASTM D1557. It should be noted that maximum dry density and optimum moisture content is dependent on the properties of the selected material.

7.2.4 Pipeline Settlement

Based on the results of our field investigation and review of the project plans, the majority of the proposed pipelines will be located in formational materials, either in cut portions of the alignment or buried below shallow fills and/or alluvium. Settlements in these areas are anticipated to be negligible. The eastern portion of the proposed alignment, specifically, east of boring B-5 and near the existing Jamacha Pump Station, may be underlain by fill and/or alluvium of varying thickness. Some settlement in these areas should be anticipated. The amount of settlement will generally depend on the thickness of the fill and/or alluvium beneath the pipeline. Based on our experience, an assumed vertical strain of 0.3 percent may be used for estimating fill and alluvium settlements beneath the pipe. For example, a pipeline underlain by about 15 feet of fill and/or alluvium can be expected to experience about ½ inch of total settlement. A pipeline underlain by about 5 feet of fill and/or alluvium can be expected to experience less than ¼ inch of total settlement. It should be noted that areas of deeper fills and/or alluvium may exist along the proposed pipeline alignment which were not encountered in our borings.

7.2.5 Trench Resurfacing

Trench resurfacing (pavement replacement) should conform to the minimum requirements of the County of San Diego. We recommend resurfacing in accordance with San Diego Regional Standard Drawings Nos. G-24A and G-24B (2018). Resurfacing efforts should satisfy the minimum requirements of the County of San Diego project inspector, which may be more stringent.

7.2.6 Thrust Blocks

For level ground conditions, a passive earth pressure of 300 psf per foot of depth below the lowest adjacent final grade can be used to compute allowable thrust block resistance. A value of 120 psf per foot should be used below groundwater level, if encountered.

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7.3 Soil Corrosivity

A representative sample of the on-site soils from the project alignment was tested to evaluate corrosion potential. The test results are presented in Appendix II. The project design engineer can use the sulfate results in conjunction with ACI 318 to specify the water/cement ratio, compressive strength, and cementitious material types for concrete exposed to soil. A corrosion engineer should be contacted to provide specific corrosion control recommendations.

8. GEOTECHNICAL ENGINEERING DURING CONSTRUCTION

The geotechnical engineer should review project plans and specifications prior to bidding and construction to check that the intent of the recommendations in this report has been incorporated.

Observations and tests should be performed during construction. If the conditions encountered during construction differ from those anticipated based on the subsurface exploration program, the presence of the geotechnical engineer during construction will enable an evaluation of the exposed conditions and modifications of the recommendations in this report or development of additional recommendations in a timely manner.

9. CLOSURE

Atlas should be advised of changes in the project scope so that the recommendations contained in this report can be evaluated with respect to the revised plans. Changes in recommendations will be verified in writing. The findings in this report are valid as of the date of this report. Changes in the condition of the site can, however, occur with the passage of time, whether they are due to natural processes or work on this or adjacent areas. In addition, changes in the standards of practice and government regulations can occur. Thus, the findings in this report may be invalidated wholly or in part by changes beyond our control. This report should not be relied upon after a period of two years without a review by us verifying the suitability of the conclusions and recommendations to site conditions at that time.

In the performance of our professional services, we comply with that level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions and in the same locality. The client recognizes that subsurface conditions may vary from those encountered at the exploration locations and that our data, interpretations, and recommendations are based solely on the information obtained by us. We will be responsible for those data, interpretations, and recommendations, but shall not be responsible for interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection with the work performed or to be performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings.

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10. REFERENCES

American Concrete Institute (ACI) (2014), Building Code Requirements for Structural Concrete (ACI 318-14) and Commentary, dated September.

Black & Veatch (2020), 30% Design Submittal, Plans for Construction of Jamacha Sewer Force Main and Gravity Main Improvements, In the Vicinity of Spring Valley, County of San Diego Department of Public Works, dated September.

California Emergency Management Agency, California Geological Survey, University of Southern California (Cal EMA) (2009), Tsunami Inundation Map for Emergency Planning, June 1.

California Department of Conservation (2020), Fault Activity Map of California (2015), maps.conservation.ca.gov/cgs/fam, accessed November.

Federal Emergency Management Agency (FEMA) (2012), FIRM Flood Insurance Rate Map, San Diego County, Firm Panel 06073C1930G, https://msc.fema.gov/portal/search, dated May 16.

“G” Force (2010), Geotechnical Evaluation for the Proposed Jamacha Pump Station Replacement, 9903 Jamacha Boulevard, Spring Valley, CA, 91977, dated March 29.

GeoTracker (2020), State Water Resources Control Board, GeoTracker, https://geotracker.waterboards.ca.gov/, accessed November.

International Code Council (2018), 2019 California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, Based on the 2018 International Building Code, Effective January 1, 2020.

Public Works Standards, Inc. (2018), “Greenbook” Standard Specifications for Public Works Construction, 2018 Edition.

San Diego Regional Standard Drawings (2018), Standard Drawings for Agencies in the San Diego Region, Recommended by the Regional Standards Committee, Maintained and Published by the County of San Diego Department of Public Works, www.regional-stds.com, dated October.

Todd, V.R. (2004), Preliminary Geologic Map of the El Cajon 30’ x 60’ Quadrangle, Southern California, California Geological Survey, Scale 1:100,000.

©2020 OpenStreet Map

SITE VICINITY MAP

Jamacha Sewer Force Main Spring Valley, California

Date:

Job No.:

By:

February, 2021

ACF

200193P5-1R

Figure:

SCALE (feet) N

1,000 2,0000

PROJECT ALIGNMENT

FIGURE 2A FIGURE 2B

FIGURE 2C

FI

GURE 2D

Date: February, 2021

ACF

200193P5-1R

REGIONAL GEOLOGY MAP Figure:

Jamacha Sewer Force Main

Spring Valley, California Job No.:

By:

EXPLANATION:

Qya

N Reference:

Todd, V.R. (2004), Preliminary Geologic Map of the El Cajon 30' x 60' Quadrangle, Southerm California, California Geological Survey, Scale 1:100,000SCALE (feet)

3,000 6,0000

Ql

Tmv

Lindavista Formation (Pleistocene or Pliocene) - Very Old Paralic Deposits, undivided (Qvop)

Mission Valley Formation (Eocene)

Young Alluvium

Qt Terrace Deposits (Pleistocene)

PROJECT ALIGNMENT

NOTE: All locations are approximate.

Ksp Santiago Peak Volcanics (Early Cretaceous)

Kc Cuyamaca Gabbro (Early Cretaceous)

To Otay Formation (Oligocene)

To To

Kgr

Kc

Kgr Granitoid Rocks (Early Cretaceous)

Date: February, 2021

FIELD INVESTIGATION

Our field investigation was performed on October 21, 2020 and October 22, 2020 and consisted of advancing a total of six borings to depths between about 3 and 20 feet below the existing ground surface using a truck-mounted drill rig equipped with a hollow stem auger and hand tools.

The boring locations were selected by Black & Veatch. Figure 2 shows the approximate locations and depths of the borings. Two Atlas geologists logged the borings and collected samples of the materials encountered.

Relatively undisturbed samples were obtained using a modified California (CAL) sampler, which is a ring-lined split tube sampler with a 3-inch outer diameter and 2½-inch inner diameter.

Standard Penetration Tests (SPT) were performed using a 2-inch outer diameter and 1⅜-inch inner diameter split tube sampler. The CAL and SPT samplers were driven with a 140-pound weight dropping 30 inches. The number of blows needed to drive the samplers the final 12 inches of an 18-inch drive is noted on the boring logs as “Driving Resistance (blows/ft of drive).”

SPT and CAL sampler refusal was encountered when 50 blows were applied during any one of the three 6-inch intervals, a total of 100 blows was applied, or there was no discernible sampler advancement during the application of 10 successive blows. The SPT penetration resistance was normalized to a safety hammer (cathead and rope) with a 60% energy transfer ratio in accordance with ASTM D6066. The normalized SPT penetration resistance is noted on the boring logs as “N60.” Disturbed bulk samples were obtained from the SPT sampler and the drill cuttings.

The soils are classified in accordance with the Unified Soil Classification System. Logs of the borings are presented in the following Figures I-1 through I-6.

VERY LOOSE

LOOSE

MEDIUM DENSE

DENSE

VERY DENSE

0 - 4

4 - 10

10 - 30

30 - 50

OVER 50

C O

A R

S E

-G R

A

IN

E D

S O

IL

S

M O

R E

T H

A N

H A

LF

IS

C O

A R

S E

R T

H A

N N

O . 2

S

IE

V

E F

IN

E

-G R

A

IN

E D

S O

IL

S

M O

R E

T H

A N

H A

LF

IS

F

IN

E R

T H

A N

N O

. 2

S

IE

V E

SANDS WITH 15%

OR MORE FINES

MAJOR DIVISIONS

0 - 2

2 - 4

4 - 8

8 - 15

15 - 30

OVER 30

RELATIVE DENSITY OF COHESIONLESS SOILS

GROUNDWATER SYMBOLS

AL

CON

COR

DS

EI

MAX

RV

PD

UC

WA

SILTY SANDS WITH OR WITHOUT GRAVEL

CLAYEY SANDS WITH OR WITHOUT GRAVEL

INORGANIC SILTS OF LOW TO MEDIUM

PLASTICITY WITH OR WITHOUT SAND OR

GRAVEL

INORGANIC CLAYS OF LOW TO MEDIUM

PLASTICITY WITH OR WITHOUT SAND OR

GRAVEL

ORGANIC SILTS OR CLAYS OF LOW TO

MEDIUM PLASTICITY WITH OR WITHOUT SAND

OR GRAVEL

INORGANIC SILTS OF HIGH PLASTICITY WITH

OR WITHOUT SAND OR GRAVEL

WELL-GRADED GRAVELS WITH OR WITHOUT

SAND

CLAYEY GRAVELS WITH OR WITHOUT SAND

SILTS AND CLAYS

LIQUID LIMIT 50% OR LESS

SILTS AND CLAYS

LIQUID LIMIT GREATER THAN 50%

SILTY GRAVELS WITH OR WITHOUT SAND

SANDS

MORE THAN HALF

COARSE FRACTION

IS FINER THAN NO.

4 SIEVE SIZE

CLEAN GRAVELS

WITH LESS THAN

15% FINES

GRAVELS WITH

15% OR MORE

FINES

CLEAN SANDS

WITH LESS THAN

15% FINES

WELL-GRADED SANDS WITH OR WITHOUT

GRAVEL

TYPICAL NAMES

RELATIVE DENSITY

INORGANIC CLAYS OF HIGH PLASTICITY WITH

OR WITHOUT SAND OR GRAVEL

ORGANIC SILTS OR CLAYS OF HIGH

PLASTICITY WITH OR WITHOUT SAND OR

GRAVEL

PEAT AND OTHER HIGHLY ORGANIC SOILS

GRAVELS

MORE THAN HALF

COARSE FRACTION

IS LARGER THAN

NO. 4 SIEVE

GW

GP

GM

GC

SW

SP

SM

SC

ML

CL

OL

MH

CH

OH

PT

POORLY GRADED SANDS WITH OR WITHOUT

GRAVEL

SAMPLE SYMBOLS

SUBSURFACE EXPLORATION LEGEND

HIGHLY ORGANIC SOILS

LABORATORY SYMBOLS

0 - 0.25

0.25 - 0.50

0.50 - 1.0

1.0 - 2.0

2.0 - 4.0

OVER 4.0

VERY SOFT

SOFT

MEDIUM STIFF

STIFF

VERY STIFF

HARD

CONSISTENCY OF COHESIVE SOILS

SPT N60

BLOWS/FOOT

SAMPLE TYPES

CONSISTENCY SPT N60

BLOWS/FOOT

NUMBER OF BLOWS OF 140 LB HAMMER FALLING 30 INCHES TO DRIVE A 2 INCH O.D.

(1-3/8 INCH I.D.) SPLIT-BARREL SAMPLER THE LAST 12 INCHES OF AN 18-INCH DRIVE

(ASTM-1586 STANDARD PENETRATION TEST).

IF THE SEATING INTERVAL (1st 6 INCH INTERVAL) IS NOT ACHEIVED, N IS REPORTED AS

REF.

POCKET PENETROMETER

MEASUREMENT (TSF)

Modified California Sampler

Bulk Sample

WATER LEVEL AT TIME OF EXCAVATION

OR AS INDICATED

ATTERBERG LIMITS

CONSOLIDATION

CORROSIVITY TESTING

DIRECT SHEAR

EXPANSION INDEX

MAXIMUM DENSITY

R-VALUE

PARTICLE-SIZE DISTRIBUTION

UNCONFINED COMPRESSIVE STRENGTH

No. 200 WASH (% PASSING No. 200 SIEVE)

Bulk Sample

CAL

SPT Standard Penetration Test

POORLY GRADED GRAVELS WITH OR

WITHOUT SAND

C O

P Y

L E

G E

N D

N E

W

1/

/2

7:

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IA

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A C

R

IM

E N

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IN

G \2

7F

N A

V F

A C

S W

, C O

A S

T A

L C

A M

P U

S K

T

R A

IN

IN

G F

A C

IL

IT

Y P

G I -

P A

C R

IM

\R

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O R

T S

\A P

P I

B

O R

IN

G

L O

G S

\2

7F

B O

R

IN

G L

O G

S .G

P J

Atlas Technical Consultants 6280 Riverdale Street San Diego, California 92120 Telephone: (707)-775-7959

PD, AL

9 inches of Asphalt Concrete over 12 inches of Aggregate Base.

FILL (Qf): CLAYEY SAND (SC), medium dense, brown, moist, fine to coarse grained.

Inv. El. ±338

BORING TERMINATED AT 3 FEET DUE TO RISK OF UTILITY CONFLICT

BORING DIA. (in.)

START

DEPTH/ELEV. GROUND WATER (ft)

SITE

10/22/20

END

REVIEWED BY

Manual

SAMPLING METHOD

SHEET NO.

Spring Valley, California

DRILL METHOD

AKN

NOTES

D E

P T

H (f t)

E

LE

V A

T

IO

N (f t)

AT TIME OF DRILLING ---

AT END OF DRILLING ---

AFTER DRILLING ---

LOGGED BY

Jamacha Force Main and Gravity Main Improvements

ATLAS PROJECT NAME

200193P5-1R

Manual

10/22/20

Hand Auger

DRILLING COMPANY

TOTAL DEPTH (ft) GROUND ELEV. (ft)

ATLAS PROJECT NUMBER

3 ± 349

LOG OF TEST BORING

DJM

DRILLING EQUIPMENT

B-1

Figure

THIS SUMMARY APPLIES ONLY AT THE LOCATION

OF THIS BORING AND AT THE TIME OF DRILLING.

SUBSURFACE CONDITIONS MAY DIFFER AT OTHER

LOCATIONS AND MAY CHANGE AT THIS LOCATION

WITH THE PASSAGE OF TIME. THE DATA

PRESENTED IS A SIMPLIFICATION OF THE ACTUAL

CONDITIONS ENCOUNTERED.

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Atlas Technical Consultants LLC 6280 Riverdale Street San Diego, California 92120 Telephone: 619.280.4321

A T

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LAB

TESTS

G R

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DESCRIPTION AND CLASSIFICATION

SPT

SPT

SPT

PD, AL

PD, AL

74/11"

50/6"

87/11"

9 inches of Asphalt Concrete over 12 inches of Aggregate Base.

FILL (Qf): SANDY fat CLAY (CH), stiff, brown, moist, fine to coarse grained.

MISSION VALLEY FORMATION (Tmv): CLAYEY SANDSTONE, strongly cemented, weathered, mottled light and yellowish brown, moist, breaks down to dense CLAYEY SAND (SC), strongly cemented, fine to coarse grained.

Inv. El. 344½

Breaks down to CLAYEY SAND with GRAVEL (SC).

SILTY SANDSTONE, weathered, dark gray, moist, breaks down to very dense SILTY SAND with GRAVEL (SM), strongly cemented, fine to coarse grained.

SANTIAGO PEAK VOLCANICS (Ksp): Dark gray, dry, weathered, breaks down to very dense SILTY SAND (SM).

BORING REFUSAL AT 15½ FEET ON SANTIAGO PEAK VOLCANICS

Hammer Efficiency = 70.6% N60~1.18NSPT

BORING DIA. (in.)

START

DEPTH/ELEV. GROUND WATER (ft)

SITE

10/22/20

END

REVIEWED BY

Manual

SAMPLING METHOD

SHEET NO.

Baja Exploration

Spring Valley, California

DRILL METHOD

AKN

NOTES

D E

P T

H (f t)

E

LE

V A

T

IO

N (f t)

AT TIME OF DRILLING ---

AT END OF DRILLING ---

AFTER DRILLING ---

LOGGED BY

Jamacha Force Main and Gravity Main Improvements

ATLAS PROJECT NAME

200193P5-1R

Manual

10/22/20

CME-95

DRILLING COMPANY

TOTAL DEPTH (ft) GROUND ELEV. (ft)

ATLAS PROJECT NUMBER

15.5 ± 352

LOG OF TEST BORING

DJM

DRILLING EQUIPMENT

B-2

Figure

THIS SUMMARY APPLIES ONLY AT THE LOCATION

OF THIS BORING AND AT THE TIME OF DRILLING.

SUBSURFACE CONDITIONS MAY DIFFER AT OTHER

LOCATIONS AND MAY CHANGE AT THIS LOCATION

WITH THE PASSAGE OF TIME. THE DATA

PRESENTED IS A SIMPLIFICATION OF THE ACTUAL

CONDITIONS ENCOUNTERED.

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Atlas Technical Consultants LLC 6280 Riverdale Street San Diego, California 92120 Telephone: 619.280.4321

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LAB

TESTS

B

LO

W S

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N

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IC

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SPT

SPT

PD, AL

10 inches of Asphalt Concrete.

FILL (Qf): SILTY GRAVEL with SAND (GM), very dense, yellowish brown, moist, fine to coarse grained.

MISSION VALLEY FORMATION (Tmv): CLAYEY SANDSTONE, light brown, moist, slightly weathered, breaks down to very dense CLAYEY SAND (SC), moderately cemented, fine grained, manganese oxide staining.

SILTY SANDSTONE, reddish brown, moist, breaks down to very dense SILTY SAND (SM), moderately cemented, fine to medium grained.

Inv. El. 318½

SANDSTONE, decreased fines content, light brown, weakly cemented, breaks down to dense POORLY-GRADED SAND (SP).

Increased fines content, breaks down to dense well-graded SAND with SILT (SW-SM).

CLAYSTONE, brown, moist, slightly weathered, breaks down to hard LEAN CLAY (CL), well indurated, fine grained.

BORING TERMINATED AT 16½ FEET

Hammer Efficiency = 70.6% N60~1.18NSPT

BORING DIA. (in.)

START

DEPTH/ELEV. GROUND WATER (ft)

SITE

10/22/20

END

REVIEWED BY

Manual

SAMPLING METHOD

SHEET NO.

Baja Exploration

Spring Valley, California

DRILL METHOD

AKN

NOTES

D E

P T

H (f t)

E

LE

V A

T

IO

N (f t)

AT TIME OF DRILLING ---

AT END OF DRILLING ---

AFTER DRILLING ---

LOGGED BY

Jamacha Force Main and Gravity Main Improvements

ATLAS PROJECT NAME

200193P5-1R

Manual

10/22/20

CME-95

DRILLING COMPANY

TOTAL DEPTH (ft) GROUND ELEV. (ft)

ATLAS PROJECT NUMBER

16.5 ± 324

LOG OF TEST BORING

DJM

DRILLING EQUIPMENT

B-3

Figure

THIS SUMMARY APPLIES ONLY AT THE LOCATION

OF THIS BORING AND AT THE TIME OF DRILLING.

SUBSURFACE CONDITIONS MAY DIFFER AT OTHER

LOCATIONS AND MAY CHANGE AT THIS LOCATION

WITH THE PASSAGE OF TIME. THE DATA

PRESENTED IS A SIMPLIFICATION OF THE ACTUAL

CONDITIONS ENCOUNTERED.

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LAB

TESTS

B

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N

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PD, AL

50/1"

6 inches of Asphalt Concrete over 3½ inches of Aggregate Base.

FILL (Qf): CLAYEY SAND with GRAVEL (SC), medium dense, brown, moist, fine to coarse grained.

Inv. El. 284 Concrete.

BORING REFUSAL AT 6½ FEET ON CONCRETE, POSSIBLE UTILITY

ENCASEMENT

Hammer Efficiency = 70.6% N60~1.18NSPT

BORING DIA. (in.)

START

DEPTH/ELEV. GROUND WATER (ft)

SITE

10/22/20

END

REVIEWED BY

Manual

SAMPLING METHOD

SHEET NO.

Baja Exploration

Spring Valley, California

DRILL METHOD

AKN

NOTES

D E

P T

H (f t)

E

LE

V A

T

IO

N (f t)

AT TIME OF DRILLING ---

AT END OF DRILLING ---

AFTER DRILLING ---

LOGGED BY

Jamacha Force Main and Gravity Main Improvements

ATLAS PROJECT NAME

200193P5-1R

Manual

10/22/20

CME-95

DRILLING COMPANY

TOTAL DEPTH (ft) GROUND ELEV. (ft)

ATLAS PROJECT NUMBER

6.5 ± 289

LOG OF TEST BORING

DJM

DRILLING EQUIPMENT

B-4

Figure

THIS SUMMARY APPLIES ONLY AT THE LOCATION

OF THIS BORING AND AT THE TIME OF DRILLING.

SUBSURFACE CONDITIONS MAY DIFFER AT OTHER

LOCATIONS AND MAY CHANGE AT THIS LOCATION

WITH THE PASSAGE OF TIME. THE DATA

PRESENTED IS A SIMPLIFICATION OF THE ACTUAL

CONDITIONS ENCOUNTERED.

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Atlas Technical Consultants LLC 6280 Riverdale Street San Diego, California 92120 Telephone: 619.280.4321

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\A

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I\ A

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B O

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G L

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S .G

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LAB

TESTS

B

LO

W S

P E

R F

O O

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N

G R

A P

H

IC

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SPT

SPT

PD, SA

10 inches of Asphalt Concrete over 6 inches of Fill.

VERY OLD PARALIC DEPOSITS (Qvop): COBBLE CONGLOMERATE with CLAYEY SAND matrix, reddish brown to brown, damp to moist, breaks down to medium dense CLAYEY GRAVEL with SAND (GC), moderately cemented, fine to coarse grained.

Inv. El. 263

Strongly cemented.

SANDY SILTSTONE, reddish brown to brown, moist, weathered, breaks down to hard SANDY SILT (ML), strongly cemented, fine to medium grained, manganese oxide staining.

SILTY SANDSTONE, reddish brown to brown, moist, weathered, breaks down to medium dense SILTY SAND (SM), moderately cemented, fine to medium grained, manganese oxide staining.

Less fines.

BORING TERMINATED AT 20 FEET

Hammer Efficiency = 70.6% N60~1.18NSPT

BORING DIA. (in.)

START

DEPTH/ELEV. GROUND WATER (ft)

SITE

10/21/20

END

REVIEWED BY

Manual

SAMPLING METHOD

SHEET NO.

Baja Exploration

Spring Valley, California

DRILL METHOD

AKN

NOTES

D E

P T

H (f t)

E

LE

V A

T

IO

N (f t)

AT TIME OF DRILLING ---

AT END OF DRILLING ---

AFTER DRILLING ---

LOGGED BY

Jamacha Force Main and Gravity Main Improvements

ATLAS PROJECT NAME

200193P5-1R

Manual

10/21/20

CME-95

DRILLING COMPANY

TOTAL DEPTH (ft) GROUND ELEV. (ft)

ATLAS PROJECT NUMBER

20 ± 268

LOG OF TEST BORING

DJM

DRILLING EQUIPMENT

B-5

Figure

THIS SUMMARY APPLIES ONLY AT THE LOCATION

OF THIS BORING AND AT THE TIME OF DRILLING.

SUBSURFACE CONDITIONS MAY DIFFER AT OTHER

LOCATIONS AND MAY CHANGE AT THIS LOCATION

WITH THE PASSAGE OF TIME. THE DATA

PRESENTED IS A SIMPLIFICATION OF THE ACTUAL

CONDITIONS ENCOUNTERED.

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Atlas Technical Consultants LLC 6280 Riverdale Street San Diego, California 92120 Telephone: 619.280.4321

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LAB

TESTS

B

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W S

P E

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N

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H

IC

LO

CAL

CAL

SPT

SPT

PD, AL

24.1

18.4

99.1

111.9

6 inches of Asphalt Concrete over 15 inches of Aggregate Base.

FILL (Qf): SANDY lean CLAY (CL), soft to medium stiff, brown, moist, fine to coarse grained.

QUATERNARY YOUNG ALLUVIUM (Qya): SANDY SILT (ML), stiff, mottled reddish brown and brown, moist, fine grained, weathered, manganese oxide staining, micaceous.

Lean CLAY (CL), stiff, reddish brown and brown, moist, fine grained, weathered, oxidation staining, manganese oxide staining, micaceous.

Interbedding of CLAYEY SAND (SC) and SANDY LEAN CLAY (CL).

Poorly graded SAND (SP), very loose, brown to gray, moist, fine to coarse grained.

VERY OLD PARALIC DEPOSITS (Qvop): SANDY CLAYSTONE, reddish brown, moist, weathered, well indurated, fine to coarse grained, white percipitate, breaks down to very stiff to hard SANDY CLAY (CL).

Trace gravel, iron oxide staining.

BORING TERMINATED AT 20 FEET

Hammer Efficiency = 70.6% N60~1.18NSPT

BORING DIA. (in.)

START

DEPTH/ELEV. GROUND WATER (ft)

SITE

10/21/20

END

REVIEWED BY

Manual

SAMPLING METHOD

SHEET NO.

Baja Exploration

Spring Valley, California

DRILL METHOD

AKN

NOTES

D E

P T

H (f t)

E

LE

V A

T

IO

N (f t)

AT TIME OF DRILLING ---

AT END OF DRILLING ---

AFTER DRILLING ---

LOGGED BY

Jamacha Force Main and Gravity Main Improvements

ATLAS PROJECT NAME

200193P5-1R

Manual

10/21/20

CME-95

DRILLING COMPANY

TOTAL DEPTH (ft) GROUND ELEV. (ft)

ATLAS PROJECT NUMBER

20 ± 255

LOG OF TEST BORING

DJM

DRILLING EQUIPMENT

B-6

Figure

THIS SUMMARY APPLIES ONLY AT THE LOCATION

OF THIS BORING AND AT THE TIME OF DRILLING.

SUBSURFACE CONDITIONS MAY DIFFER AT OTHER

LOCATIONS AND MAY CHANGE AT THIS LOCATION

WITH THE PASSAGE OF TIME. THE DATA

PRESENTED IS A SIMPLIFICATION OF THE ACTUAL

CONDITIONS ENCOUNTERED.

I-6

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Atlas Technical Consultants LLC 6280 Riverdale Street San Diego, California 92120 Telephone: 619.280.4321

A T

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2/ 7/

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W E

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I - B

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G L

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LAB

TESTS

B

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W S

P E

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O O

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N

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U R

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D R

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S

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G R

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LABORATORY TESTING

Laboratory tests were performed to provide geotechnical parameters for engineering analyses.

The following tests were performed:

CLASSIFICATION: Field classifications were verified in the laboratory by visual examination. The final soil classifications are in accordance with the Unified Soil Classification System.

IN SITU MOISTURE AND DENSITY: The in situ moisture content and dry unit weight were determined on samples collected from the borings. The test results are presented on the boring logs in Appendix I.

PARTICLE-SIZE DISTRIBUTION: Particle-size distribution testing was performed on selected soil samples in accordance with ASTM D6913.

ATTERBERG LIMITS: Atterberg limits testing was performed on selected soil samples in accordance with ASTM D4318.

CORROSIVITY: Corrosivity testing was performed on a selected soil sample. The pH and minimum resistivity testing were performed in accordance with California Test 643 and ASTM G51. The soluble chloride content testing was performed in accordance with California Test 422. The soluble sulfate content testing was performed in accordance with California Test 417.

Soil samples not tested are stored in our laboratory for future reference and analysis, if needed.

Unless notified to the contrary, samples will be disposed of 30 days from the date of this report.

Date:

Job Number: Figure:200193P5-1R II-1

SAMPLE NUMBER PLASTIC LIMIT

59415 PLASTICITY INDEX

Jamacha Force Main and Gravity Main Improvements

Spring Valley, California

By:

LIQUID LIMIT

GLC February, 2021

SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: SC ATTERBERG LIMITS

B-1 at 1½ to 3 Feet DESCRIPTION CLAYEY SAND

0.010.11101001000 Grain Size in Millimeters

U.S. Standard Sieve Sizes

Pe rc en t F in er b y

W ei gh t

Cobbles Gravel

Coarse Fine

Sand

Coarse Medium Fine

Silt or Clay

6" 3" 3/4" 1-½" 3/8" #4 #10 #8 #30 #16 #50 #40 #100 #200

Date:

Job Number: Figure:200193P5-1R II-2

SAMPLE NUMBER PLASTIC LIMIT

59416 PLASTICITY INDEX

Jamacha Force Main and Gravity Main Improvements

Spring Valley, California

By:

LIQUID LIMIT

GLC February, 2021

SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: CH ATTERBERG LIMITS

B-2 at 1½ to 5 Feet DESCRIPTION SANDY fat CLAY

0.010.11101001000 Grain Size in Millimeters

U.S. Standard Sieve Sizes

Pe rc en t F in er b y

W ei gh t

Cobbles Gravel

Coarse Fine

Sand

Coarse Medium Fine

6" 3" 3/4" 1-½" 3/8" #4 #10 #8 #30 #16 #50 #40 #100 #200

Date:

Job Number: Figure:200193P5-1R II-3

SAMPLE NUMBER PLASTIC LIMIT

59417 PLASTICITY INDEX

Jamacha Force Main and Gravity Main Improvements

Spring Valley, California

By:

LIQUID LIMIT

GLC February, 2021

SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: SC ATTERBERG LIMITS

B-2 at 10½ to 11½ Feet CLAYEY SAND with GRAVEL

DESCRIPTION

0.010.11101001000 Grain Size in Millimeters

U.S. Standard Sieve Sizes

Pe rc en t F in er b y

W ei gh t

Cobbles Gravel

Coarse Fine

Sand

Coarse Medium Fine

6" 3" 3/4" 1-½" 3/8" #4 #10 #8 #30 #16 #50 #40 #100 #200

NP

NP

NP

Date:

Job Number: Figure:

SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: SW-SM ATTERBERG LIMITS

200193P5-1R II-4

SAMPLE NUMBER PLASTIC LIMIT

59418 PLASTICITY INDEX

Jamacha Force Main and Gravity Main Improvements

Spring Valley, California

By:

Well-graded SAND with SILT

DESCRIPTION LIQUID LIMIT

GLC February, 2021

B-3 at 10½ to 11½ Feet

0.010.11101001000 Grain Size in Millimeters

U.S. Standard Sieve Sizes

Pe rc en t F in er b y

W ei gh t

Cobbles Gravel

Coarse Fine

Sand

Coarse Medium Fine

6" 3" 3/4" 1-½" 3/8" #4 #10 #8 #30 #16 #50 #40 #100 #200

Date:

Job Number: Figure:

SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: SC ATTERBERG LIMITS

200193P5-1R II-5

SAMPLE NUMBER PLASTIC LIMIT

59419 PLASTICITY INDEX

Jamacha Force Main and Gravity Main Improvements

Spring Valley, California

By:

CLAYEY SAND

with GRAVEL

DESCRIPTION LIQUID LIMIT

GLC February, 2021

B-4 at 1 to 5 Feet

0.010.11101001000 Grain Size in Millimeters

U.S. Standard Sieve Sizes

Pe rc en t F in er b y

W ei gh t

Cobbles Gravel

Coarse Fine

Sand

Coarse Medium Fine

6" 3" 3/4" 1-½" 3/8" #4 #10 #8 #30 #16 #50 #40 #100 #200

Date:

Job Number: Figure:200193P5-1R II-6

SAMPLE NUMBER PLASTIC LIMIT

58724 PLASTICITY INDEX

Jamacha Force Main and Gravity Main Improvements

Spring Valley, California

By:

LIQUID LIMIT

GLC February, 2021

SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: GC ATTERBERG LIMITS

B-5 at 1½ to 5 Feet CLAYEY GRAVEL with SAND

DESCRIPTION

0.010.11101001000 Grain Size in Millimeters

U.S. Standard Sieve Sizes

Pe rc en t F in er b y

W ei gh t

Cobbles Gravel

Coarse Fine

Sand

Coarse Medium Fine

6" 3" 3/4" 1-½" 3/8" #4 #10 #8 #30 #16 #50 #40 #100 #200

Date:

Job Number: Figure:200193P5-1R II-7

SAMPLE NUMBER PLASTIC LIMIT

58725 PLASTICITY INDEX

Jamacha Force Main and Gravity Main Improvements

Spring Valley, California

By:

LIQUID LIMIT

GLC February, 2021

SAMPLE LOCATION UNIFIED SOIL CLASSIFICATION: CL ATTERBERG LIMITS

B-6 at 2 to 4 Feet DESCRIPTION SANDY lean CLAY

0.010.11101001000 Grain Size in Millimeters

U.S. Standard Sieve Sizes

Pe rc en t F in er b y

W ei gh t

Cobbles Gravel

Coarse Fine

Sand

Coarse Medium Fine

6" 3" 3/4" 1-½" 3/8" #4 #10 #8 #30 #16 #50 #40 #100…