W912PL21B0003_River Road Dike_Geotechnical Baseline and Data Report_20210729.pdf

Los Angeles District®

Geotechnical Branch

GEOTECHNICAL BASELINE AND DATA REPORT

(INCLUDING HTRW)

River Road Dike Construction Contract Prado Dam Flood Control Basin Eastvale, Riverside County, California

JULY 2021

THIS PAGE LEFT INTENTIONALLY BLANK

Geotechnical Baseline and Data Report July 2021 River Road Dike Construction i

Report Prepared By:

U.S. Army Corps of Engineers Engineering Division, Geotechnical Branch 915 Wilshire Blvd, Suite 930 Los Angeles, CA 90017

Julia Yang, P.E., Project Geotechnical Engineer

Arturo Orozco, P.G., C.E.G.

Engineering Geologist

With the Assistance of:

Mark L. Russell, P.E., G.E.

Senior Geotechnical Engineer

Jung Lee, P.E.

Civil Engineer

Michael Lau, P.E.

Materials Engineer

Ryan Folk, E.I.T.

Civil Engineer

Report Reviewed by:

Douglas Dahncke, P.E., G.E., Chief, Soils Design and Materials Section B

Mark McLarty, P.G., C.E.G., Chief, Geology and Investigations Section

Jim Farley, P.E.

Chief, Geotechnical Branch

Report Edited by:

Christine Stossel Technical Writer/Editor ii

THIS PAGE LEFT INTENTIONALLY BLANK

iii

TABLE OF CONTENTS

INTRODUCTION

Purpose and Organization of Geotechnical Baseline and Data Report

Limitations of Geotechnical Baseline and Data Report

PROJECT HISTORY AND DESCRIPTION

Location and Site Description

Project Description

LABORATORY INVESTIGATIONS

Subsurface Investigations

3.1.1 Previous Subsurface Investigations on Adjacent and Nearby Parcels

3.1.2 CPT Soundings

3.1.3 Deep Exploratory Borings

3.1.4 Groundwater Monitoring Wells

3.1.5 Shallow Test Pits and Test Trenches

3.1.6 Shallow Exploratory Borings

3.1.7 Borrow Area Explorations

In-Situ Geotechnical Testing

3.2.1 Shear Wave Velocity Testing

3.2.2 Aquifer Properties Testing

Geotechnical Laboratory Testing

3.3.1 Corrosivity Tests on Foundation Soils

3.3.2 Blended Borrow Material Characteristics

TOPOGRAPHIC AND REGIONAL GEOLOGIC CONDITIONS

Topography and Drainage

Local Site Geology

4.2.1 Quaternary Very Old Alluvium (Qvoa)

4.2.2 Quaternary Young Alluvium (Qya)

4.2.3 Artificial Fill (af and Caf)

Groundwater

FINDINGS

Foundation Conditions iv

5.1.1 Topsoil and Artificial Fill

5.1.2 Alluvium

5.1.3 Foundation Consolidation and Compressibility

5.1.4 Foundation Permeability

5.1.5 Groundwater

5.1.6 Foundation Shear Strengths

Borrow Materials

Embankment Materials

GEOTECHNICAL CONSIDERATIONS AND CONSTRAINTS

Underground Utilities

Secant Pile Wall for Utility Excavation Retainment

Buried Debris and Obstructions

Borrow Materials

Abutments

REFERENCES

LIST OF FIGURES

Figure 2-1: Typical Cross Section for River Road Dike Figure 3-1: In-Situ Unit Weight and Moisture Results – Foundation Soil Samples Figure 3-2: Results of Index Tests on Borrow Samples for Embankment Materials Figure 4-1: MW17-01 Groundwater Table Elevations December 2017 – May 2021 Figure 4-2: MW17-02 Groundwater Table Elevations December 2017 – May 2021 Figure 4-3: MW18-01 Groundwater Table Elevations August 2018 – May 2021

LIST OF TABLES

Table 3-1: Reviewed Existing Subsurface Investigations in Site Vicinity Table 3-2: Summary of CPT Soundings in Current Project Area Table 3-3: Summary of Seismic CPT Test Results Table 3-4: Summary of Deep Borings Table 3-5: Summary of Monitoring Well Construction Table 3-6: Summary of Shallow Borings Table 3-7: Summary of Borrow Area Explorations Table 3-8: Summary of Moisture Content and Unit Weight for Alluvial Soils Table 3-9: Summary of Index Laboratory Testing of Borrow Materials Table 5-1: Location and Characterization of Topsoil and Artificial Fill v

Table 5-2: Summary of Consolidation Indices for Fine Grained Foundation Soils at River Road Dike Current Project Area Table 5-3: Summary of Swell/Collapse Test Results for Foundation Soils at River Road Dike . 30 Table 5-4: Summary of Foundation Laboratory Permeability Tests Table 5-5: Summary of In-Situ Permeability Tests Table 5-6: Summary of Foundation Strength Test Results

LIST OF PLATES

Plate B-1: Regional Topographic Map Plate B-2: Vicinity Map Plate B-3: Regional Geologic Map Plate B-4: Vicinity Exploration Map Plate B-5: Site Geologic Map Plate B-6: Geologic Profile of Dike Alignment Plate B-7: Geologic Cross Sections A, B, and G Plate B-8: Cross Section G continued Plate B-9: Cross Section I Plate B-10: Cross Section J

LIST OF APPENDICES

Appendix A – Subsurface Investigation Logs for Project Site

Appendix B – Groundwater Data and Pumping Test Results

Appendix C – Geotechnical Laboratory Test Results for Foundation Soils

Appendix D – Geotechnical Laboratory Test Results for Borrow Materials

INTRODUCTION

Purpose and Organization of Geotechnical Baseline and Data Report

The purpose of the Geotechnical Baseline and Data Report (GBDR) is to provide subsurface data in the project vicinity and facilitate the bidding process by providing a single contractual interpretation of the geotechnical conditions at the project site.

This report includes:

• Geologic and seismic description of the site.

• Geologic mapping, geologic and geotechnical profiles and cross sections.

• Results of geotechnical subsurface investigations at the project site and borrow area including logs of exploratory borings, CPT soundings, test pits, test trenches, and in-situ testing for shear wave velocity and permeability.

• Results of geotechnical laboratory testing of foundation soils including gradation, plasticity, permeability, consolidation, undrained shear strength, and drained shear strength.

• Results of geotechnical laboratory testing of composite soil samples from the borrow area including soil shear strength, gradation, plasticity, permeability, consolidation, and soil water characteristic curve.

• Evaluation and description of subsurface conditions including soil types and groundwater levels.

• Conclusions.

Limitations of Geotechnical Baseline and Data Report

This report presents the geotechnical engineer’s best judgement and interpretation of the subsurface conditions anticipated to be encountered during construction. The actual subsurface conditions encountered during construction are expected to be more complex and vary from assumed foundation conditions for the design. The assumed design foundation conditions were based on engineering judgement to produce conservative geotechnical parameters that can adequately represent actual foundation conditions. In addition, the actual ground condition will be influenced by construction activity and level of workmanship. It is the contractor’s responsibility to assess expected ground behavior based on data presented in the GBDR. The contract documents require bidders to consult with their geotechnical engineer, who must be familiar with all topics covered in this GBDR. The contractor’s Construction Quality Control (CQC) geotechnical engineer should have similar experience and knowledge to interpret the presented data in this GBDR to apprehend complexity of the actual subsurface conditions.

The project Contract Documents include a Differing Site Conditions clause. Deviation from anticipated subsurface conditions from contract information may be coordinated with the Contracting Officer during construction. This GBDR is intended for the Contractor in evaluating the merits of differing site condition claims, if necessary.

PROJECT HISTORY AND DESCRIPTION

Location and Site Description

The River Road Dike project is a portion of the Prado Dam project that falls within the City of Eastvale, Riverside County, California. The dike will be situated along the northeasterly boundary of the Prado Dam Reservoir Basin, approximately four miles northeast of Prado Dam.

Plate B-1 is a regional topographic map of the Prado Dam area with Prado Basin and the River Road Dike project location shown. Plate B-2 is a vicinity map with aerial photography of the project area.

Site topography slopes generally to the south-southwest. River Road is located less than a mile southeast of the proposed dike (hence the name “River Road Dike,” stemming from an earlier project plan that had the dike further to the south and contiguous with River Road). The upper end of Mill Creek is an ephemeral stream that runs through the south part of the project site. The south end of the Cucamonga Creek flood control channel crosses Hellman Avenue approx-imately 1/4 mile north of the project site, with Cucamonga Creek joining Mill Creek at a point approximately 1.5 miles southwest of the project. The California Institute for Women (CIW prison), with its two dikes, is located approximately 1.5 miles west of the River Road Dike project site.

The River Road Dike site is in the northerly part of the Prado Basin in an area formerly occupied by agricultural land (primarily dairy farms) and is now occupied by partly vacant land, with adjacent tracts of single-family residences. Numerous concrete slabs, foundations, and other debris remaining from the former dairies are visible at the ground surface. A draft Phase I Environmental Site Assessment with updated executive summary (Phase I ESA, Appendix E) conducted for this project (USACE, December 2017, updated April 2021) indicated underground fuel storage tanks and septic systems previously used at the dairies, some of which may remain at the site beneath the surface.

Project Description

The overall River Road Dike project consists primarily of a compacted earth fill embankment, approximately 1,750 feet in length to protect the nearby community that could be subject to flooding once the Prado Dam spillway is raised. At the south end (station 1+00), the dike will abut the existing raised ground of the residential tract (Tract No. 31961) in a nearly east-west direction. The dike will then turn north across Mill Creek and former dairy land and then turn west at approximately station 13+00 and parallel the south edge of residential tracts (Tract No.

30905 and Tract No. 29997), and the alignment turns 90 degrees perpendicular to the masonry wall of the housing track. The dike terminates at station 18+59 at the corner of property boundary Tract No. 30905 and Tract No. 29997.

The south abutment (south tie-in) consists of an earthen dike that ties into a secant pile wall along the private property line of the existing residential tract. The secant pile wall will consist of overlapping 48-inch diameter drilled concrete shafts with steel I-beams as reinforcing within every other pile. The secant pile wall will be approximately 240 feet long and the individual piles range from approximately 40 feet to 60 feet in depth, measured relative to the top of pile.

The north abutment (north tie-in) will involve the embankment terminating into an abutment created by the existing residential tract fill. The alignment of the dike will bend to an east-west portion prior to transitioning into the north abutment at an appropriate high ground elevation along the residential tract fill.

The dike will have a crest elevation of 567 feet. The maximum height of the dike will be approximately 15.5 feet, at station 4+30 where the outlet conduits will be situated. The crest of the dike will be 21 feet wide including a 15-foot wide access road, shoulders, and thickness of riprap on the reservoir side of the dike. Side slopes will be 2.25 horizontal to 1 vertical (2.25H:1V). The revetment on both slopes will consist of an 18-inch thick riprap layer (with 12-inch maximum stone size) over a minimum 12-inch thick layer of bedding material. The dike will be homogeneous (no internal zones). A typical dike cross section is shown on Figure 2-1.

The outlet conduits will be situated at the approximate location of the existing natural drainage (approximate station 4+60), which is the lowest current ground elevation along the dike alignment. The outlet conduits will be two 48-inch diameter side-by-side pressure pipes with reinforced concrete headwalls and flap gates at the outlet ends.

8"

T

H K

R

I P

R A

P

O

V E

R

2"

K

B

E D

D I N

G

T O

P

O

F

D

I K

E S

R E

S E

R V

O I

S

D

L A

N D

W A

X

I S

T I N

G

G

R A

D E

E X

P L O

R A

T I O

N

T

R E

N C

H

E X

C A

V A

T I O

N

8"

K

R

I P

R A

P

O

V

T

H K

B

E D

D I N

G

3'

3"

A

C

P

A V

E M

E N

T

O

V

6"

A

B C

C O

N T

R O

L

L I N

E

E N

G I N

E E

R E

D

F

I L L

SANTA ANA RIVER MAINSTEM, CALIFORNIA

PHASE II, PRADO DAM

RIVER ROAD DIKE

EASTVALE/CHINO, CALIFORNIA

TYPICAL CROSS SECTION

US Army Corps of Engineers

Los Angeles District

P l o t

D a t e

P

M

P l o t t e d b y l e d j b d

F i l

N a m e

R

I V

E R

R D

B

F

I G

U R

E

T

Y P

C

T I O

N D

W G

F i g u r e

T y p

S e c t i o n

A

FIGURE

SOURCE: U.S.A.C.E.

1-1

2-1

THIS PAGE INTENTIONALLY LEFT BLANK

LABORATORY INVESTIGATIONS

Subsurface Investigations

Subsurface investigations of the project foundation conditions were conducted in several phases:

• Previously completed subsurface investigations of parcels in the site vicinity were reviewed.

• An initial subsurface investigation of the general project area was conducted in 2017 using cone penetrometer tests (CPT).

• Three deep borings were drilled, sampled, and converted to groundwater monitoring wells, two in 2017 and another in 2018.

• Nineteen shallow test pits and test trenches were excavated at selected locations near the project area in 2017 and 2018. Four (4) of nineteen shallow test pits were within the current dike alignment.

• Six shallow exploratory borings were drilled at selected locations near the project area in 2018.

• Four shallow exploratory borings were drilled near the vicinity of the south tie-in and two north of Tract No. 29997, outside the proposed dike alignment.

• Seven test pits were excavated within the vicinities of the north and south tie-ins in 2019.

• Six additional test pits were excavated within the currently proposed borrow area in 2020.

• Following each phase of subsurface investigation, the location and elevation of each CPT sounding, test pit, and test hole/boring were surveyed by the Los Angeles District Survey and Mapping Section using the NGVD29 vertical datum and NAD 1927 horizontal datum.

The locations of the exploratory borings, CPT soundings, and test pits from all field investigations are presented on Plate B-4 Vicinity Exploration Map and Plate B-5 Site Geologic Map. Logs of the current USACE explorations are included in Appendix A.

3.1.1 Previous Subsurface Investigations on Adjacent and Nearby Parcels

The subsurface explorations shown in Table 3-1 were not on the subject site, but were reviewed and included as indicative of foundation conditions in the general site vicinity.

Table 3-1: Reviewed Existing Subsurface Investigations in Site Vicinity Source/Reference Location Test Hole/Boring/Well

USACE, 1973 Cucamonga Creek Channel TH71-8, TH71-9, TT70-34 CHJ, Inc., 2005 Lennar Tract B-1 through B-7

Kleinfelder, 2002 Tract 30576 Borings 1 – 12 Pacific Soils, 2004 Tract 29677 HS-1 through HS-5 Petra Geotechnical

(included in PS, 2004) Tract 29677 B-1 through B-8

GeoSoils, 2007 Tract 31543, Reagan School B-1 through B-10 Gaston, 2016 14325 Chandler Street MW-1 through MW-7

3.1.2 CPT Soundings

The cone penetrometer test soundings (CPT17-01 through CPT17-08) were advanced to depths of 35 to 79 feet below existing grade on 23-24 October 2017 by Gregg Drilling and Testing, subcontracted to AECOM, under contract with USACE. The CPT soundings were conducted using an integrated electronic cone system with pressure transducers to measure tip resistance (qc), sleeve friction resistance (fs), and penetration pore water pressure (u2) in accordance with ASTM D5778. Measurements were taken at 10-centimeter (cm) depth intervals. Pore pressure dissipation tests (PPDT’s) were conducted at selected depths as a means of estimating the static groundwater head. Table 3-2 summarizes the pertinent CPT soundings near the currently proposed project alignment.

Table 3-2: Summary of CPT Soundings in Current Project Area

CPT

Sounding Approx.

Station

Approx. Ground Elevation (feet NGVD 29)

Total Depth of Sounding (feet)

Depths of PPDT (feet)

CPT17-02 9+00 561.08 75 38.0, 73.1

CPT17-03 4+50 558.27 70 40.3, 69.7

CPT17-08 18+00 558.81 47 —

Seismic cone penetration tests were conducted at CPT17-05 and CPT17-08 to measure shear wave velocity (Vs) (see Table 3-3).

Table 3-3: Summary of Seismic CPT Test Results

CPT17-05 CPT17-08

Test Depth (feet)

Shear Wave Velocity (feet per second) Test Depth

(feet) Shear Wave Velocity

(feet per second)

15.09 649.8 15.42 1119.2

20.18 796.9 20.34 859.3

25.26 1045.5 25.59 951.7

30.35 735.6 30.68 1720.6

35.27 819.1 35.27 1019.3

40.19 768.2 40.19 1092.5

45.28 696.1 45.28 1069.7

50.03 576.3 — —

54.46 1321.4 — —

3.1.3 Deep Exploratory Borings

Two deep borings (TH17-01 and TH17-02) were advanced to depths of 100 feet below existing grade on 6-10 November 2017. The borings were drilled using a 5.5-inch diameter tri-cone bit and rotary wash techniques to reduce potential for borehole caving below groundwater. A third deep boring (TH18-01) was advanced to a depth of 53 feet below existing grade on 25 July 2018.

That boring was drilled using an 8-inch diameter hollow stem auger. Soil samples were collected at 5-foot intervals typically alternating between the Standard Penetration Test (SPT) ASTM D1586 and California Modified samples ASTM D3550M. Higher quality undisturbed samples were collected using Shelby tube samplers.

The logs of borings TH17-01, TH17-02, and TH18-01 are included in Appendix A. Table 3-4 summarizes depth of the deep borings.

Table 3-4: Summary of Deep Borings Boring Number

Approx.

Station

Ground Elevation (feet

NGVD29)

Total Depth of Boring (feet) Well Number

TH17-01 5+00 537.6 100 MW17-01

TH17-02 n/a 559.0 100 MW17-02 TH18-01 n/a 561.6 53 MW18-01

3.1.4 Groundwater Monitoring Wells

Groundwater monitoring (observation) wells (MW17-01 and MW17-02) were installed in both of the 100-foot deep exploratory borings. The upper 70 feet of both of the 5.5-inch borings were reamed to 8-inch diameter prior to installing the wells. The bottom 30 feet of those two borings were backfilled with soil cuttings. A groundwater monitoring well was also installed in boring TH18-01 to a depth of 50 feet. Well depths and elevations are summarized on Table 3-5.

Table 3-5: Summary of Monitoring Well Construction

Well Number

Top of Casing Elevation

(feet NGVD29)

Total Depth of Well (feet)

Depth to Water at Installation (feet)/ Elevation (feet)

Screened Interval

Elevation (feet)

MW17-01 556.83 70.0 14.8/539.8 484.6–544.6

MW17-02 560.79 70.0 19.8/539.2 489.0–549.0

MW18-01 563.81 50.0 25.6/535.9 511.5–526.5

Groundwater conditions are discussed within Section 3.5 and data is included in Appendix B.

Well-completion diagrams for the monitoring wells are shown on the boring logs in Appendix A.

3.1.5 Shallow Test Pits and Test Trenches

Nine shallow exploratory test pits (TP17-01 through TP17-09) were excavated by backhoe to depths of 4 to 14 feet below existing grade on 1 to 2 December 2017. A test trench (TT17-01), approximately 42 feet long and approximately 6 feet deep, was excavated on 1 December 2017 to investigate fill and topsoil contacts in more detail. Another nine test pits (TP18-01 through TP18-09) were excavated on 2 to 3 February 2018.

In February and October 2019, seven additional shallow exploratory test pits (TP19-01 through TP19-07) were excavated to the maximum depths of approximately 7 feet below existing grade in the vicinities of the north and south tie-ins to evaluate the existing fill and natural materials.

The current borrow area was reduced in size from its original configuration; therefore 4 previously excavated test pits cover this area. In March 2020, six additional exploratory test pits (TP20-01 through TP20-06) were excavated within the proposed borrow area to further characterize the soils.

Some test pits were along the dike alignment to provide information about the dike foundation.

Some test pits are along the alignment and near the adjacent borrow area to provide both foundation and borrow area information. The remaining test pits were within the borrow area and were strictly for the purpose of borrow area investigation.

Test pits and the test trench along the current dike alignment included: TP17-02, TP17-04, TP17- 06, TP17-07, TP17-08, TT17-01, TP19-01, TP19-02, TP19-03, TP19-04, TP19-05, TP19-06 and TP19-07. Some of these are close to the borrow area and detention pond areas and so they represent both foundation conditions and excavation/borrow materials.

The following test pits were within the currently designated borrow area southwest of the dike alignment and strictly represent areas of excavation where embankment fill materials may be obtained: TP17-09,TP18-05, TP18-06, TP18-07, TP20-01, TP20-02, TP20-03, TP20-04, TP20- 05, and TP20-06.

Soils exposed in the test pits were logged and sampled by a USACE geologist. Disturbed (bulk bag) samples were collected for classification purposes and soils observed in the test pits and test trench were classified using the Unified Soils Classification System visual-manual procedure (ASTM D2488). Relatively undisturbed samples were collected at selected depths and locations from the test pits using a California modified sampler with a hand-operated slide hammer or pushed in with the backhoe bucket. In a few selected locations where soils were somewhat softer, Shelby tube samplers were pushed in with the backhoe bucket to retrieve relatively undisturbed samples. Relatively undisturbed samples along the dike alignment were used for laboratory testing of engineering properties. Relatively undisturbed samples within the borrow area were used to obtain unit weights for calculation of shrinkage and bulking. At selected locations and depths, a nuclear density gauge (ASTM D6938) was used to determine in-place soil moisture and density. The logs of the test pits and test trenches are included in Appendix A.

3.1.6 Shallow Exploratory Borings

Shallower borings were advanced to depths of 25 feet below existing grade on 23 to 24 July 2018; reference Table 3-6. Similar sampling method used for the deep boring was used for the shallow exploratory borings. Seven additional shallow exploratory test pits were drilled in the vicinities of the north and south tie-ins to maximum depths of 16 to 25 feet below existing grade in February and October 2019; reference Table 3-6. The logs of pertinent shallow exploratory borings are included in Appendix A.

Table 3-6: Summary of Shallow Borings

Number

Approx.

Station/ Location

Approx. Ground Elevation

(feet NGVD29)

Total Depth of Boring (feet)

Area of Investigation

TH18-05 14+50 563.4 25 Foundation TH18-06 10+00 561.9 25 Foundation TH18-07 Borrow area 556.1 25 Borrow TH19-01 1+00 565.4 25 Foundation TH19-02 1+00 564.8 25 Foundation TH19-03 1+00 560.7 25 Foundation TH19-04 1+00 561 16 Foundation

3.1.7 Borrow Area Explorations

Of the subsurface exploration points discussed above, the test pits and boring that represent the soils to be excavated (within or adjacent to designated borrow area or detention pond excavation areas) are summarized on Table 3-7.

Table 3-7: Summary of Borrow Area Explorations

Exploration Point

Total Depth (feet)

Approximate Design Borrow Excavation

Depth (feet)

Bulk Samples within Borrow Excavation

Depth

Soil Types in Borrow

Excavation Depth

TP17-03 5 2 (5.0) CL, SC

TP17-09 11 9 (1.0–2.0)(5.0–6.0)(7.0–

-7.5)

CL, ML, SM, SP-

SM

TT17-01 12 2 (0-1.0) SM

TP18-01 4 4 (1.0–3.0)(1.0–4.0) SC, CL

TP18-02 10 4 (0–2.0)(3.0–4.0) SP, SC

TP18-03 13 10 (2.0–2.5)(3.5–4.0)(5.0–

6.0)(8.5–9.0) ML, CL, MH, ML

TP18-04 12.5 5 (3.0–3.5)(3.5–4.0) CL, SP-SC

TP18-05 15 10 (3.0–3.5)(5.0–5.5)(6.0–

6.5)(8.0–9.0) MH, SM, CL

TP18-06 11 1 (1.0–2.0) CL

TP 18-07 25 — — SC, SP-SM, SP

TP20-01 11.5 11.5 lowest adjacent grade (2.0–7.0)(7.0–11) SM, SP

TP20-02 22 10, from lowest adjacent grade

(4.0–12.0)(12.0–

21.0)(21.0–22.0) SM, SM, SP

TP20-03 20 10, from lowest adjacent grade

(2.0–7.0)(18.0–

19.0)(19.0–20.0) SM, ML, SP

TP20-04 14 14 (1.5–3.0)(3.0–5.5)(5.5–

11.0)(11.0–14.0)

CL, ML, ML, SP-

SM

TP20-05 11 10 (2.0–6.5)(6.5–7.5)(7.5–

11.0) ML, SP, SP

TP20-06 14.5 10 (0.5–4.5)(8.0–14.5) SW-SM, ML

In-Situ Geotechnical Testing

3.2.1 Shear Wave Velocity Testing

In-situ geophysical testing for shear wave velocity of the foundation soils was conducted in association with the CPT soundings. Seismic cone penetration tests were conducted at CPT17-05 and CPT17-08 to measure shear wave velocity (Vs) as a method to estimate stiffness of the soil profile (reference Table 3-3). The weighted averages are 749 feet per second (fps) for CPT17-05 and 1085 fps for CPT17-08.

3.2.2 Aquifer Properties Testing

Groundwater pumping tests were conducted by AECOM in groundwater observation wells with 4-inch ID PVC casing (MW17-01 and MW17-02) on 6 December 2017. The stepped rate pumping tests were conducted in accordance with ASTM D4050 to evaluate the permeability (hydraulic conductivity) of the upper foundation soils. Slug tests (ASTM D4044) were initially conducted but found not to give useful results, so the pumping tests were conducted. The pumping tests involved continuously recording water levels in the wells through two 30-minute pumping periods and a full recovery period. Flow rates varied from 10 to 18 gallons per minute (gpm) and recovery times varies from 15 to 20 minutes. Pumping test results are discussed in Section 5.1.4.2. The pumping test procedures and computations for transmissivity and hydraulic conductivity are presented in Appendix B.

Geotechnical Laboratory Testing

Geotechnical laboratory testing was performed on disturbed and undisturbed samples collected during the subsurface investigations. Index tests and engineering property tests were performed in the laboratory testing. Refer to Appendix C for the laboratory test results of tests on exploration samples within the dike foundation areas. Refer to Appendix D for the laboratory test results of remolded samples of anticipated embankment fill materials.

Based on the laboratory test results on soil samples obtained in the project area, the moisture and dry unit weight values are summarized in the Table 3-8. Dry unit weight compared with moisture content data for various soil types is presented in Figure 3-1.

Table 3-8: Summary of Moisture Content and Unit Weight for Alluvial Soils Moisture Content

Dry Unit Weight (pcf)

Upper 10 feet Material

(51 samples)

Range 5.52–26.5 88.8–121.6 Average 14.1 106.9

Std Deviation 4.4 6.7

SANTA ANA RIVER MAINSTEM, CALIFORNIA

PHASE II, PRADO DAM

RIVER ROAD DIKE

EASTVALE/CHINO, CALIFORNIA

IN-SITU UNIT WEIGHT AND MOISTURE RESULTS

US Army Corps of Engineers Los Angeles District

Pl ot

D at e:

/2 0/

:5

9:

A M

, P lo tte d by : l

1e d9 jb d, F ile

N am e:

R

IV

ER

R D

_B

_F

IG

U R

E 3-

1_ W

T- M

O

IS

TU

R

E R

ES

U

LT

S.

D W

G

Fi gu re

-1 _W t-M oi st ur e R es ul ts (A

FIGURE

SOURCE: U.S.A.C.E.

3-1

3.3.1 Corrosivity Tests on Foundation Soils

Corrosion characteristic tests were performed on two samples of near-surface soils from the site, one near the south end (TH17-01) and one at the north end (TH17-02). The pH of the tested samples ranged from 6.9 to 7.1 and the electrical resistivity ranged from 8400 to 11600 ohm-centimeters for soil moisture as received from the field. The chloride content ranged from 3 to 48 parts per million (ppm, mg/kg) while the sulfate content ranged from 52 to 119 ppm, mg/kg.

3.3.2 Blended Borrow Material Characteristics

For analysis, composite soils were made up in the laboratory using the various individual bulk soil samples collected from test pits and borings in the borrow area. First the sandy soils deeper than 10 feet were composited and labeled as “coarse” material, and the shallower mixed sandy, silt and clay soils were composited as “fine” material. Then two composite blends were made up the two different proportions of the coarser and finer materials to represent the range of soil blending that may occur during construction.

Composite blend sample 1 was 80 percent shallower/finer soils and 20 percent deeper coarser soils. Composite blend sample 2 was 20 percent shallower/finer soils and 80 percent deeper coarser soils. The index properties of the two composite samples are summarized on Table 3-9 and shown graphically on Figure 3-2. The two composite samples are assumed to bracket the range of soils that can reasonably be expected in the dike embankment.

Table 3-9: Summary of Index Laboratory Testing of Borrow Materials Composite

Sample Number

Material

Soil Type

USCS

gravel fines LL PI ωopt γd, max

(pcf)

1 Upper, finer grained soil (80-20 blend) SC 4 41 41 19 12.0 117.0

Deeper, coarser grained soil (20-80 blend)

SC 4 14 36 16 9.3 122.2

RIVER ROAD DIKE

EASTVALE/CHINO, CALIFORNIA

RESULTS OF INDEX TESTS ON BORROW SAMPLES FOR

EMBANKMENT MATERIALS

US Army Corps of Engineers

Los Angeles District

P l o t

D a t

P

M

P l o t t e d b y l e d j b d

F i l

N m e

R

I V

E R

R D

B

F

I G

U R

E

B

O R

R O

W S

A M

P L E

S D

W

F i g u r e

B o r r o w m p l e s

A

FIGURE

4-33-2

TOPOGRAPHIC AND REGIONAL GEOLOGIC CONDITIONS

Geologic conditions within the vicinity of River Road Dike project were determined from review of published references, review of historic aerial photographs, site reconnaissance and site subsurface exploration. A listing of published references is provided at the end of this report.

The project site is located upstream from Prado Dam and the adjoining easterly end of Santa Ana Canyon, within the Prado Flood Control Basin. The Prado Flood Control Basin (Prado Basin) forms the westerly portion of the Upper Santa Ana River Valley, and the subject portion of the basin is bounded on the south and southeast by the Santa Ana River and La Sierra/Norco Hills, and on the west by the Puente Hills. A broad plain of coalescing alluvial fan deposits extend north from the area of the Prado Basin to the foothills of the San Gabriel Mountains, which are the primary source area for these deposits. The overall surface gradient of this alluvial plain is inclined gently to the south, but the gradient steepens to the north approaching the San Gabriel Mountains. Chino Creek, San Antonio Creek, and Cucamonga Creek are the principal modern drainages that control southward flow from the San Gabriel Mountains, but there are numerous intermediate drainage courses that also carry storm flow across this portion of Prado Basin including Temescal Wash and Mill Creek. All of these drainages are tributary to the Santa Ana River (refer to Plate B-2).

Topography and Drainage

The topography in the immediate vicinity of the project site can be generally characterized as a dissected and undular terrace surface between intervening drainage courses of the Cucamonga and Mill Creeks. In contrast to the primarily depositional environment of the broad alluvial plain to the north of the project. The River Road Dike will be situated on a remnant terrace surface in the dissected transition area between the broad alluvial plain to the north and the generally subdued and flat-lying relief of the Prado Flood Control Basin to the south. The natural topography in the vicinity of the project has been obscured by grading associated with previous dairy farm operations, tract development and previous land use. The remnant topography has an overall slope that is inclined gently to the southerly direction.

Surface drainage and fall across the site is northerly to southerly direction except areas that north of Chandler Avenue, the ground surface slopes northwest toward Cucamonga Creek. Cucamonga Creek is a concrete-lined trapezoidal flood control channel extending from the base of the Cucamonga Canyon Dam, near 23rd street in the City of Upland to Hellman Avenue just north of Chandler Street. Southwesterly of Hellman Avenue, Cucamonga Creek is unlined and extends into the wetlands of Prado Basin where it converges with Mill Creek that flows toward the southwest.

The primary source of the fill used to construct the dike will be from the required excavations and from the designated “Borrow Area” west of the Dike. The borrow area consists of gently sloping terrain east of Hellman Avenue that drains toward the southwest. The demolition and grading materials associated with the previous dairy farm obscure the ground surface along with concrete slabs, footings, asphalt and gravel roads that remain within the borrow area.

Local Site Geology

Mapped deposits beneath the River Road Dike project site are shown on the Geologic Map (Plate B-5) and consist of: Quaternary Very Old Alluvium (Qvoa) consisting of Middle to Early Pleistocene moderately- to well-consolidated highly dissected clay, silt, sand and gravel;

Quaternary Young Alluvium (Qya) consisting of Holocene to Late Pleistocene unconsolidated to slightly consolidated, undissected to slightly dissected clay silt sand and gravel; and Artificial Fill (af) (Bedrossian and Roffers, 2012). Quaternary Young Alluvial Fan Deposits (Qyf) consisting of Holocene to Late Pleistocene unconsolidated to slightly consolidated, undissected to slightly dissected boulder, cobble, gravel, sand and silt deposits; and Quaternary Very Old Fan Deposits (Qvof) consisting of moderately- to well-consolidated, highly-dissected clay, silt, sand and gravel occur northerly and westerly of the project site as shown on the Regional Geologic Map (Plate B-3).

The nearby portion of the alluvial plain is located about a mile north of the site and represents the extreme southerly edge of coalescing fan deposition associated with southward flow from the San Gabriel Mountains that has formed a wedge or veneer of young alluvium (Qya and Qyf) over the Very Old Alluvial Fan Deposits (Qvof). Aging and deep weathering of the Qvof has produced a significant residual clay content and associated low permeability conditions. In contrast, the overlying wedge of young alluvium contains relatively little clay and has commensurately higher permeability characteristics. These contrasting permeability character-istics created local artesian groundwater conditions along the westerly and southerly margin of the nearby alluvial plain where southerly subsurface flow in the young alluvium was forced to the surface by the underlying wedge of Qvof. During recent geologic time and persisting in some areas to the present day, surface seepage and marshes were present along the channels that were incised down through the Qvof and into the southerly margin of the young alluvial plain to the north. Areas of historical artesian groundwater conditions are reported in some geologic literature as well as bogs, swamps, and marshlands along the lower portions of the Cucamonga and Mill Creek drainages. As encountered during the course of grading construction of the California Institute For Women Dike (CIW, USACE Geotechnical report dated 2015), these unique local geologic conditions resulted in growth of apparently lush vegetation under generally arid climatic and artesian conditions, and development of a relatively thick sequence of near-surface organic soils along the channel that comprises much of the foundation area for the CIW North Dike. However, artesian groundwater conditions have not been encountered in any of the subsurface exploration or monitoring wells at the River Road Dike site.

4.2.1 Quaternary Very Old Alluvium (Qvoa)

Quaternary Very Old Alluvium (Qvoa) consists of Middle to Early Pleistocene moderately- to well-consolidated, highly-dissected clay, silt, sand and gravel valley deposits occurring within stream valleys. Occurrences of the various soil-type subunits are generally discontinuous throughout the deposit due to the variable geometry and temporal variability commonly associated with aggrading and degrading fluvial deposition and erosion. These deposits are generally uplifted and deformed and locally overlie Tertiary marine sedimentary rocks. Qvoa is mapped locally between the Santa Ana River and Cucamonga Creek, with an aerial extent of approximately 6 miles long by up to 1 mile wide. The unit is partially dissected at its southwesterly extent by Qya associated with Mill Creek and Cucamonga Creek, and at its southeasterly margin by modern channel deposits of the Santa Ana River. Young alluvial fan deposits cover the Qvoa to the north and northwest.

Qvoa is the oldest unit encountered within the subsurface explorations and generally exhibits a higher degree of consolidation and pedological development or “illuviation” than the overlying Qya. Such features observed within the subsurface explorations include secondary clay and carbonate mineralization, orange to yellowish-brown oxidation staining and blocky pedoligic structure.

4.2.2 Quaternary Young Alluvium (Qya)

Quaternary Young Alluvium (Qya) consists of Holocene to Late Pleistocene unconsolidated to slightly consolidated, undissected to slightly dissected clay silt sand and gravel and occurs locally within a zone of up to about 500 feet wide and extending in a northeast to southwest direction along Mill Creek, and overlying Qvoa. Occurrences of the various soil-type subunits are generally discontinuous throughout the deposit due to the variable geometry and temporal variability commonly associated with aggrading and degrading fluvial deposition and erosion.

Qya is also mapped north of the proposed dike alignment where it was deposited by Cucamonga Creek, as well as to the west where it is related to a smaller dendritic stream. Qya is generally less consolidated than Qvoa with generally weaker soil development. The deepest occurrence of Qya encountered in the site subsurface explorations is 18 feet at TH17-01 and is estimated to be perhaps slightly deeper toward the southwest along Mill Creek.

4.2.3 Artificial Fill (af and Caf)

Various undocumented fills (af) of limited thickness (less than 3–4 feet) are present along most of the alignment and throughout much of the site. These undocumented fills are interpreted to be related to the previous dairy farming activities. Debris observed in the subsurface explorations included boulders, asphalt, plastic, metal, lumber, concrete, and steel pipe. Compacted fill (Caf) is mapped at the site and includes artificial fill that was placed for development of the adjacent residential tracts to the north and east of the dike alignment.

Groundwater

Pore pressure dissipation tests in the CPT soundings gave initial indications of groundwater levels, ranging from 14 feet to 29 feet below existing grade, prior to drilling the borings. After drilling and installing groundwater monitoring wells at the site, detailed groundwater level monitoring was conducted using in-well pressure transducers.

Detailed groundwater level data obtained from the monitoring wells is included in Appendix B and presented in Figures 4-1, 4-2, and 4-3.

Based on these data, the groundwater flows to the southwest at a gradient of approximately

0.0013 feet/foot. For comparison, groundwater monitoring reports for a nearby site (14325 Chandler Street, approximately 0.6 miles northeast, up-gradient of the River Road Dike alignment) shows groundwater surface elevations ranging between 541.3 and 544.4 from 2010 to 2016 (Gaston 2016). Groundwater level monitoring in the first two wells began in December 2017 and for MW18-01, began in August 2018. Figures 4-1 through 4-3 present a graphic depiction of groundwater table elevations and precipitation from December 2017 to December 2020. The data show a slight seasonal variation in groundwater levels of generally less than two feet, with generally punctuated response to precipitation events.

RIVER ROAD DIKE

EASTVALE/CHINO, CALIFORNIA

MW17-01 GROUNDWATER TABLE ELEVATIONS

DECEMBER 2017 - MAY 2021

US Army Corps of Engineers Los Angeles District

Pl ot

D at e:

/2 7/

2:

:1

PM

, P lo tte d by : l

1e d9 jb d, F ile

N am e:

R

IV

ER

R D

_B

_F

IG

U R

E 3-

2_ M

W

-0 1_

G W

.D W

G

Fi gu re

-2 _M

W

-0

G W

(A

FIGURE

4 1

RIVER ROAD DIKE

EASTVALE/CHINO, CALIFORNIA

MW17-02 GROUNDWATER TABLE ELEVATIONS

DECEMBER 2017 - MAY 2021

US Army Corps of Engineers Los Angeles District

Pl ot

D at e:

/2 7/

2:

:2

PM

, P lo tte d by : l

1e d9 jb d, F ile

N am e:

R

IV

ER

R D

_B

_F

IG

U R

E 3-

3_ M

W

-0 2_

G W

.D W

G

Fi gu re

-3 _M

W

-0

G W

(A

FIGURE

4 2

RIVER ROAD DIKE

EASTVALE/CHINO, CALIFORNIA

MW18-01 GROUNDWATER TABLE ELEVATIONS

AUGUST 2018 - MAY 2021

US Army Corps of Engineers Los Angeles District

Pl ot

D at e:

/2 7/

2:

:4

PM

, P lo tte d by : l

1e d9 jb d, F ile

N am e:

R

IV

ER

R D

_B

_F

IG

U R

E 3-

4_ M

W

-0 1_

G W

.D W

G

Fi gu re

-4 _M

W

-0

G W

(A

FIGURE

4 3

THIS PAGE INTENTIONALLY LEFT BLANK

FINDINGS

Foundation Conditions

Foundation soils include both younger and older alluvial sediments (map symbols Qa and Qvoa).

These soils vary widely in texture, density, and stiffness along the project alignment, in part due to the variable geometry and temporal variability commonly associated with aggrading and degrading fluvial deposition and erosion. Soil types encountered in the foundation vary from highly plastic clays (CH soil type) through virtually the whole range of soil classifications to gravels (GP-GM soil type). Lenses and layers of the various soil types are inter-fingered and occur at various depths.

Subsurface profiles and cross sections were developed along the project alignment based on subsurface investigations and laboratory testing. Interpolation and extrapolation between test hole or test pit locations were made with engineering judgement and do not reflect actual foundation conditions. Presented geologic profiles and cross sections in the Plates B-6 through B-10 are to establish baseline conditions for quantifying satisfactory materials used in the construction of the project.

5.1.1 Topsoil and Artificial Fill

Topsoil and artificial fill are considered to be unsatisfactory for support the proposed embankment and the associated structures. Excavated artificial fill that is free of construction debris and meets the requirement of satisfactory material may be reused for General Fill or Embankment Fill. Topsoil was encountered mostly at the 1 feet to 3 feet below existing grade, generally consisted of sandy clay, silt, clayey sand to silty sand. Artificial fill from previous construction varied widely between upper 1 feet to 13 feet. Artificial fill primarily consisted of sandy clay, silty sand to sand. Compacted artificial fill for the residential tracts to the north and south tie-ins are considerably deeper at maximum of 13 feet in depth. The estimated thickness and characteristics of topsoil and artificial fill are summarized in Table 5-1.

Table 5-1: Location and Characterization of Topsoil and Artificial Fill

Boring Depth (feet) Characterization

TH17-01 0 to 1.5 Undocumented Artificial fill, clayey sand TH17-02 0 to 1.5 Artificial fill, silty sand TH18-04 0 to 5.5 Artificial fill, sandy lean clay TH18-05 0 to 2.5 Artificial fill, sandy lean clay to sand TH18-06 0 to 2.5 Artificial fill TH19-01 0 to 8.5 Compacted fill, silty sand to silty clay TH19-02 0 to 10.5 Compacted fill, clayey sand TH19-03 0 to 4.5 Compacted fill, clayey sand TP17-01 0 to 3 Artificial fill, topsoil, clayey sand to sandy clay TP17-02 0 to 3 Artificial fill, topsoil, silty sand to sandy clay TP17-03 0 to 1 Artificial fill, sandy clay with gravel

Boring Depth (feet) Characterization

TP17-04 0 to 3 Topsoil, silty sand TP17-05 0 to 3 Topsoil, sandy clay

TP17-06 0 to 2 Artificial fill, topsoil, clayey sand to clayey sand with gravel

TP17-07 0 to 3 Artificial fill, clayey sand to clayey sand TP17-08 0 to 1.5 Topsoil, sandy clay TP17-09 0 to 3.5 Topsoil, sandy clay TT17-01 0 to 2 Topsoil, artificial fill, silty sand TP18-01 0 to 3.5 Artificial fill, clayey sand TP18-02 0 to 2.5 Artificial fill, sand TP18-03 0 to 5 Artificial fill, topsoil, silt to sandy clay TP18-04 0 to 1.5 Artificial fill, clay TP18-05 0 to 2.5 Topsoil, silt TP18-06 0 to 1 Topsoil, sandy clay TP19-01 0 to 5.5 Artificial fill, clayey sand to sandy clay TP19-02 0 to 13 Artificial fill, clayey sand TP19-03 0 to 7 Compacted fill, clayey sand TP19-05 0 to 9 Compacted fill, sandy clay to sand TP19-06 0 to 4 Artificial fill, topsoil, sandy clay

5.1.2 Alluvium

Quaternary very old and young alluvium (geologic map symbols Qya and Qvoa) was predominantly encountered beneath surficial topsoil and/or artificial deposits. The alluvium deposits are generally comprised of sandy material with lenses of fine-grained soils. The excavated younger and older alluvium are suitable for use as Embankment Fill and General Fill.

5.1.3 Foundation Consolidation and Compressibility

One-dimensional consolidation tests were conducted primarily on samples of the fine-grained soils (silts and clays). Table 5-2 summarizes the consolidation test result data.

Table 5-2: Summary of Consolidation Indices for Fine Grained Foundation Soils at River

Road Dike Current Project Area

Approx.

Station

Ground Elev.

(feet)

Depth (feet)

USCS

Soil Type

Geologic Map Unit

OCR Cc Cr Cv at σ'o (ft2/day) Cα

TH17-01 5+00 554.6 13 CL Qya 3.0 0.08 0.02 3.5 0.0024 TH17-01 5+00 554.6 29 ML Qvoa 1.9 0.09 0.02 2.7 0.0027 TH17-01 5+00 554.6 58 CH Qvoa 2.6 0.23 0.02 3.4 0.0069

Average values: 2.5 0.133 0.02 3.2 0.004

Table 5-3 shows the results of one-dimensional swell/collapse tests conducted on selected shallow foundation soil samples. The clayey sand soil was found to have a slight collapse potential (0.7%) while the clay soils were found to be slightly expansive (0.1% to 0.3% swell).

Table 5-3: Summary of Swell/Collapse Test Results for Foundation Soils at River Road Dike

Approx.

Station

Ground Elev.

(feet)

Depth (feet)

USCS

Soil Type

Geologic Map Unit

Swell or Collapse upon saturation

TH18-04 22+50 559.7 5.0 CL af Swell 0.1%

5.1.4 Foundation Permeability

5.1.4.1 Laboratory Permeability Testing of Foundation Samples

Laboratory permeability tests were performed on clay and clayey sand samples collected within the upper 20 feet during the 2017 and 2018 field investigations (reference Table 5-4). The permeability of sandy foundation soils was considered better represented by the in-situ permeability tests (pumping tests) and correlations with grain size discussed in sections 5.1.4.1 and 5.1.4.2.

Table 5-4: Summary of Foundation Laboratory Permeability Tests Boring/ Test Pit

Approx.

Station

Ground Elev.

(feet)

Depth (feet)

USCS

Soil Type

Geologic Map Unit

Confining Pressure

(psi) k (cm/s) k (ft/day)

TH17-01 5+00 554.6 9.0 SC

8.5 2.3E-07 6.52E-04

Qya 17.3 2.2E-07 6.24E-04

24.4 1.8E-07 5.10E-04

TP17-06 5+50 555.1 5.0 SC 5.0 1.9E-04 5.39E-01

Qya 19.2 7.5E-05 2.13E-01

TP17-07 4+00 554.3 5.5 SC Qya 5.9 2.40E-06 6.80E-03 Maximum 1.9E-04 5.39E-01 Minimum 1.8E-07 5.10E-04

5.1.4.2 In-Situ Permeability/Aquifer Testing

Pumping tests on the two groundwater monitoring wells were conducted during the initial geotechnical investigation in 2017. Pumping test procedures and results are included in Appendix B. Hydraulic conductivity (permeability) values from the field pump testing ranged from 11 to 62 feet per day (fpd) representing roughly the upper 50 feet of foundation soils as shown in Table 5-5.

Table 5-5: Summary of In-Situ Permeability Tests

Well

Approx.

Station

Approx.

Ground Elev.

(feet)

Well Screen Depth (feet)

Computed Effective Aquifer

Thickness (feet)

Geologic Map Units

Hydraulic Conductivity (Permeability) k (gpd/ft2) k (cm/s) k (ft/day)

MW17-01 4+50 554.6 10-70 55.9 Qya/ Qvoa 464.8 2.2E-02 62.1

The in-situ pump test results are considered to be representative of the hydraulic conductivity of the foundation. The installed length of the well screens penetrated highly layered and varying foundation soil types, so the pump test results do not isolate specific soil types, rather they probably reflect the permeability of the most pervious foundation layers intersected by the wells.

For bidding purposes, assume the in-situ aquifer permeability ranges from 1 to 100 fpd. The aquifer is defined as the coarse-grained layer (i.e., sandy foundation soils) underlying the finer-grained foundation materials (i.e. clayey, clayey sand, etc.). The results of aquifer pumping tests are presented in Appendix B.

5.1.5 Groundwater

For bidding purposes, assume groundwater to be no higher than elevation 542 feet within the project vicinity.

5.1.6 Foundation Shear Strengths

The shear strength of foundation soils was estimated from laboratory strength tests. Triaxial unconsolidated-undrained (UU; also referred to as the Quick “Q” test), triaxial consolidated-undrained with pore pressure measurements (CU; also referred to as rapid “R” test), and direct shear (DS) tests were conducted on samples collected for the investigations. Foundation shear strength test results are summarized on Table 5-6.

Table 5-6: Summary of Foundation Strength Test Results Undrained Conditions Drained Conditions

Test Pit

Depth (feet)

Type

USCS

Map Unit

Test

Total Stress (Q)

Total Stress (R)

Effective Stress (R-bar)

Effective Stress, Ultimate (DS)

Unconsolidated Su (psf)

Cohesion, c (psf)

Friction Angle, φ

(deg)

Cohesion, c’ (psf)

Friction Angle, φ’

(deg)

Cohesion, c’ (psf)

Friction Angle, φ’

(deg) Coarse Grained Soils

TH17-

01 2.5 SM Qya C-U -- 50 35 175 35 -- --

TT17-

01 4.0 SM Qvoa DS -- -- -- -- -- 234 35

TP17-04 5.0 SM Qya DS -- -- -- -- -- 266 35

TH18-

05 15.3 SM Qvoa DS -- -- -- -- -- 109 40

Undrained Conditions Drained Conditions

Test Pit

Depth (feet)

USCS

Map Unit

Test

Total Stress (Q)

Total Stress (R)

Effective Stress (R-bar)

Effective Stress, Ultimate (DS)

Unconsolidated Su (psf)

Cohesion, c (psf)

Friction Angle, φ

(deg)

Cohesion, c’ (psf)

Friction Angle, φ’

(deg)

Cohesion, c’ (psf)

Friction Angle, φ’

(deg)

TH18-

06 15.0 SW-

SM Qvoa DS -- -- -- -- -- 97 41

Fine Grained Soils

TH17-

01 13.5 CL Qya DS -- -- -- -- 476 26

TH18-

04 16.5 CL Qvoa C-U -- 0 30 6 33 -- --

TH18-

04b 17.0 ML Qvoa C-U -- 1374 14 358 29 -- --

TH18-

06 25.5 CL Qvoa U-U 1037 -- -- -- -- -- --

Notes:

(1) U-U tests at field moisture content, less than saturated.

(2) Consolidated-undrained strength values based on maximum deviator stress results.

Borrow Materials

For bidding purposes, assume the upper 10 feet of borrow material will have the following in-situ properties:

1. Dry soil unit weight: 100 to 115 PCF;

2. Moisture content: 9 to 19 percent;

3. Bulking factor: 20 to 40 percent, and;

4. Shrinkage factor: 8 to 13 percent.

Embankment Materials

The proposed project borrow area is on the reservoir side of the dike; however, much of the embankment fill material will come from required excavations in the exploration trench and along the dike footprint. Based on the geotechnical explorations, these soils are similar to the soils found in the designated borrow area; therefore, the values presented herein, which are based on samples from the borrow area, should be reasonably representative of all soils that may be used to construct River Road Dike.

The vegetation, fill, organic material and debris will need to be cleared before the borrow site materials are processed and used in…