rfb_13199_for_info_only_12-geotechnical_data_report.pdf

GEOTECHNCIAL DATA REPORT

Cole Grade Road Improvements

Valley Center, California

County Contract No. 557947 Task Order No. 20

Oracle Project No. 1003046

Prepared for:

Mr. E. David Gasaway County of San Diego

Department of Public Works Materials Lab

5252 Kearny Villa Way San Diego, CA 92123

Prepared by:

WSP USA Environment & Infrastructure, Inc.

9177 Sky Park Court

San Diego, California 92123 (858)-278-3600

November 18, 2024

WSP Project No. 5015-18-0024.20 https://www.wsp.com/

GEOTECHNICAL DATA REPORT

Valley Center, California

November 18, 2024

WSP Project No. 5015-18-0024.20

This report was prepared by the staff of WSP USA Environment & Infrastructure, Inc., under the supervision of the engineer and geologist whose seals and signatures appear hereon.

The findings, recommendations, specifications, or professional opinions are presented within the limits described by the client, in accordance with generally accepted professional engineering and geologic practice. No warranty is expressed or implied.

Mike Farr, C.E.G. #1938 Principal Engineering Geologist

Hari Ponnaboyina, G.E. #3108 Associate Geotechnical Engineer

Wood Environment & Infrastructure Solutions, Inc.

Ashwood Street Corridor Improvements, Project No. 5015-15-0013.09

TABLE OF CONTENTS

Page

1.0 PROJECT DESCRIPTION AND SCOPE OF SERVICES

2.0 SITE DESCRIPTION

3.0 FIELD INVESTIGATION

3.1 PRE-DRILLING ACTIVITIES

3.2 EXPLORATORY BORINGS

4.0 LABORATORY TESTING

5.0 SUBSURFACE CONDITIONS

5.1 GENERAL

5.2 GRANITIC BEDROCK

5.3 SLOPEWASH/RESIDUAL SOIL

5.4 ARTIFICIAL FILL

5.5 GROUNDWATER

6.0 REFERENCES

PLATES

Plates 1-3 Boring Location Maps

APPENDICES

Appendix A Field Exploration/Boring Logs Appendix B Laboratory Testing

Cole Grade Road Improvements, Project No. 5015-18-0024.20 1

GEOTECHNICAL DATA REPORT

Valley Center, California

WSP USA Environment and Infrastructure, Inc. (WSP) is pleased to present our geotechnical data report for the subject project.

1.0 PROJECT DESCRIPTION AND SCOPE OF SERVICES

We understand the overall project will consist of the widening of Cole Grade Road, extending from Fruitvale Road on the south to Oak Glen Road on the north, in Valley Center, California. The main purpose of the widening will be to increase roadway safety by constructing a center left turn lane. Geotechnical evaluations for the project were previously completed by Ninyo and Moore

(2012, 2014). The County of San Diego Department of Public Works (County) requested WSP to obtain additional subsurface information from three specific locations within the overall project site, as described in Section 2.0 below.

To assist in the preparation of this report, we were provided with preliminary plans and profiles for the planned streeting widening, including suggested boring locations. Our scope of services was limited to the three specific locations listed in Section 2.0 and did not include acceptance of previous geotechnical work performed by others or becoming the geotechnical engineer of record for the overall project.

Our geotechnical study was performed in general accordance with our proposal dated March 7, 2024, as authorized by County Task Order No. 20. The purpose of the study was to obtain information about subsurface conditions underlying the three boring locations and to provide geotechnical data to the County for their use in pavement design. Our scope of services generally consisted of:

• Pre-drilling activities, including permitting, subsurface utility screening, and logistics.

• Field investigation program consisting of 3 hollow-stem auger borings.

• Laboratory testing.

• Preparation of this report presenting the geotechnical data obtained from our study.

Services related to environmental assessment, characterization, and/or remediation were not part of the requested scope of work, and investigations or analyses of potential environmental contaminants have not been conducted or presented as part of this study.

2.0 SITE DESCRIPTION

The overall project site consists of Cole Grade Road, extending from Fruitvale Road on the south to Oak Glen Road on the north, in Valley Center, California. Cole Grade Road is a two-lane, moderately traveled, paved roadway providing access between Valley Center and rural communities to the north. The roadway is divided by a double yellow line, without a left turn lane.

Paved and unpaved shoulders of variable widths extend from the edges of the travel lanes to the right-of-way boundaries on either side of the roadway. Improvements within the right-of-way include power lines and communications lines on both sides of the roadway.

Cole Grade Road Improvements, Project No. 5015-18-0024.20 2

This study is limited to three boring locations specified by the County:

• Boring BH1 is located in the unpaved northbound shoulder of Cole Grade Road, approximately 200 feet south of White Star Lane, at an approximate elevation of 1,533 feet above mean sea level (msl).

• Boring BH2 is located in the paved southbound shoulder of Cole Grade Road, approximately 500 feet south of Margarita Lane, at an approximate elevation of 1,490 feet msl.

• Boring BH3 is located in the unpaved southbound shoulder of Cole Grade Road, approximately 100 feet north of Via Valencia, at an approximate elevation of 1,492 feet msl.

3.0 FIELD INVESTIGATION

The field investigation included predrilling activities and three exploratory borings. A brief description of the field investigation is provided below, while boring logs and a more detailed description of the field investigation are presented in Appendix A.

3.1 Pre-Drilling Activities

Pre-drilling activities included review of relevant project documents, permitting, and subsurface utility screening.

3.2 Exploratory Borings

Three exploratory borings extending to depths ranging from 5.5 feet to 10 feet were drilled at the approximate locations indicated on Plates 1 through 3. The borings were drilled with a truck-mounted Marl M10 hollow-stem auger rig operated by Pacific Drilling of San Diego, California.

The borings were drilled to obtain samples for laboratory testing and subsurface information to aid in pavement design.

4.0 LABORATORY TESTING

All laboratory testing was performed in-house by WSP. Tests performed included sieve analysis, in-situ moisture content and dry density, R-value, and expansion index. Testing was performed in accordance with ASTM and/or California Department of Transportation (Caltrans) methods. Test results and a more detailed description of the laboratory testing program are presented in

Appendix B.

5.0 SUBSURFACE CONDITIONS

5.1 General

The three boring locations are underlain by granitic bedrock, undifferentiated slopewash/residual soils, and artificial fill. The approximate distribution of these geologic units at the three boring locations is depicted on Plates 1 through 3. Detailed descriptions of the soil and rock materials encountered in the exploratory borings are presented in the boring logs in Appendix A, while a brief summary is provided in Sections 5.2 through 5.5 below. A summary of the range of depth for each geologic unit at each boring location is provided in Table 1 below.

5.2 Granitic Bedrock

Granitic bedrock associated with the Southern California Batholith underlies all three boring locations. The granitic rock encountered in our borings is assigned to the Cretaceous-age Cole

Grade Tonalite. Tonalite is an intrusive igneous rock similar to granite but containing more

Cole Grade Road Improvements, Project No. 5015-18-0024.20 3 plagioclase feldspar and less potassium feldspar than granite. The primary mineral constituents of these rocks are plagioclase feldspar and quartz, with subordinate amounts of biotite and hornblende, and minor to trace amounts of other minerals. The tonalite encountered in the borings is generally massive (non-foliated), fine- to medium-grained, off-white to tan to reddish-brown, highly weathered, very weak to extremely weak, and friable.

5.3 Slopewash/Residual Soil

Undifferentiated slopewash/residual soil was encountered overlying the granitic rock in all three borings. These deposits varied somewhat in composition between the three borings. In Boring

BH1, these deposits consisted of light reddish-brown, dry, medium dense, fine-grained clayey sand. In Boring BH2, these deposits consisted of dark reddish-brown, moist, medium dense, fine-grained clayey sand/sandy clay. In Boring BH3, these deposits consisted of reddish-brown, damp, medium dense, fine- to medium-grained silty sand.

5.4 Artificial Fill

Artificial fill soils were encountered in Borings BH2 and BH3. In Boring BH2, located in the paved southbound shoulder of Cole Grade Road, the fill was overlain by 8 inches of asphaltic concrete over 6 inches of aggregate base, and extended to a depth of 3 feet. This fill consisted of dark reddish-brown, moist, loose to medium dense, fine- to medium-grained, clayey sand and silty sand. The 3-foot fill depth at this location was somewhat unexpected given that there are no obvious fill slopes or other topographic features near the location of Boring BH2 suggesting that fill is present. It appears likely that the fill at Boring BH2 is associated with the filling of a ravine or depression.

In Boring BH3, fill extended to a depth of 1 foot, and consisted of reddish-brown, damp, loose to medium dense, fine- to coarse-grained, silty sand. Based on the topographic expression of a fill slope to the west of Cole Grade Road, the fill appears to increase in depth to the north of Boring

BH2, extending to as estimated maximum depth of about 4 to 5 feet at approximately 400 feet north of Boring BH2.

Table 1 – Range of Depth of Geologic Units

Boring Depth Range Geologic Unit

BH1

0’-1.5’ Slopewash/Residual Soil

1.5’+ Highly Weathered Granitic Rock

BH2

0’-14” 8” AC over 6” Aggregate Base

14”-3.0’ Artificial Fill

3.0’-6.0’ Slopewash/Residual Soil

6.0’+ Highly Weathered Granitic Rock

BH3

0’-1.0’ Artificial Fill

1.0’-2.0’ Slopewash/Residual Soil

2.0’+ Highly Weathered Granitic Rock

5.5 Groundwater

Groundwater or water seepage was not encountered in our exploratory borings, and are not expected to be a factor in the vicinity of the three borings either during or after construction for the proposed street widening.

Cole Grade Road Improvements, Project No. 5015-18-0024.20 4

6.0 REFERENCES

Ninyo & Moore, October 2, 2012, Geotechnical Evaluation, Cole Grade Road Improvements, Valley Center, California, Oracle Project 1003046, N&M Project No. 106898005.

Ninyo & Moore, June 12, 2014, Supplemental Geotechnical Evaluation, Cole Grade Road Improvements, Valley Center, California, Oracle Project 1003046, N&M Project No. 106898005.

Cole Grade Road Improvements, Project No. 5015-18-0024.20

PLATES

158 159 160 161 162 163 164 165 166

BH1

1.5' KtKt

COLE GRADE ROAD

(1

5)

(15

(1

3)

(1

2)

(1541)

(15

(1

9)

(1

8)

(1

7)

(1

6)

(15

(15

(15

(1532) (1531)

(1530) (1529)

(1528) (15

(1

6)

(1

5)

(1

4)

(1

3)

(1

2)

(1

1)

(1

0)

(1

9)

(1

8)

M

AR

G

AR

IT

A

LA

N

E

LA

N E

D W

Y (D

IR

T)

D W

Y (A

C

Path: G:\Other_offices\5015 San Diego\5015-18-0024 Cole Grade Site Topo\CAD\DWG\180024_Plates_Plot-Plan.dwg [1] Date: July 19, 2024 - 9:28am By: USVN717902

0 50' 100'

SCALE: 1" = 100' 5015-18-0024

Boring Location Map - BH1

Cole Grade Road Improvements

PLATE NO.

PROJECT NO.

BY:

SCALE:

DATE:

1" = 100'

CHKD:

MF

MF

07/19/2024

VMNPREPARED BY:

WSP USA

9177 Sky Park Court San Diego, California 92123 Phone (858) 278-3600 wsp.com

M

AT

C H

LI

N

E

7+

M

AT

C H

LI

N

E

6+

LEGEND

Approximate Boring LocationBH1 Depth to Bedrock (Highly Weathered Rock) at Boring Location

1.5'

Cole Grade TonaliteKt

2,018' to Cool Valley Ranch Road

149 150 151 152 153 154 155 156 157

BH2Qaf Kt

Qaf Kt

6'

COLE GRADE ROAD

(1

7)

(1

6)

(1

5)

(1

4)

(1

3)

(1

2)

(1

1)(1510)

(1509)

(1508)

(1507)

(1506)

(1505)

(1504)

(1503)

(1502)

(1501)

(1500)

(1499)

(1498)

(1497)

(1496)

(1495)

(1494)

(1493)

(1492)

(1491)

(1490)

(1489)

(1488)

(1487)

(1486)

(1485)

(1484)

(1483)

(1482)

(1481)

(1480)

(1479)

(1478)

(1477)

(1476)

(1475) (1474)

D W

Y (A

C

PR

IV

AT

E

D W

Y (A

C

Path: G:\Other_offices\5015 San Diego\5015-18-0024 Cole Grade Site Topo\CAD\DWG\180024_Plates_Plot-Plan.dwg [2] Date: July 19, 2024 - 9:29am By: USVN717902

0 50' 100'

SCALE: 1" = 100' 5015-18-0024

Boring Location Map - BH2

Cole Grade Road Improvements

PLATE NO.

PROJECT NO.

BY:

SCALE:

DATE:

1" = 100'

CHKD:

MF

MF

07/19/2024

VMNPREPARED BY:

WSP USA

9177 Sky Park Court San Diego, California 92123 Phone (858) 278-3600 wsp.com

M

AT

C H

LI

N

E

8+

M

AT

C H

LI

N

E

7+

LEGEND

Approximate Boring LocationBH1

Shallow/Localized Artificial Fill Over Cole Grade Tonalite

Depth to Bedrock (Highly Weathered Rock) at Boring Location

6'

Qaf Kt

25' to

MARGARITA

LANE

1,118' to Cool

(D

IR

T D

W Y)

68 69 70 71 72 73 74 75 76

VI

A

VA

LE

N C

IA

(A

C

C O

LE

G

R

AD

E R

D (A

C

BH3

Qaf

Kt

Kt

Kt

Kt

1'

6'COLE GRADE ROAD

(1482) (1483)

(1484)

(1485)

(1486)

(1487)

(1488)

(1489)

(1490)

(1491)

(1492)

(1493)

(1494)

(1495)

(1496)

(1497)

(1498)

(1499)

(1500)

(1501)

(1502)

(1503)

(1504)

(1505)

(1506)

(1507)

(1508)

Path: G:\Other_offices\5015 San Diego\5015-18-0024 Cole Grade Site Topo\CAD\DWG\180024_Plates_Plot-Plan.dwg [3] Date: July 19, 2024 - 9:30am By: USVN717902

0 50' 100'

SCALE: 1" = 100' 5015-18-0024

Boring Location Map - BH3

Cole Grade Road Improvements

PLATE NO.

PROJECT NO.

BY:

SCALE:

DATE:

1" = 100'

CHKD:

MF

MF

07/19/2024

VMNPREPARED BY:

WSP USA

9177 Sky Park Court San Diego, California 92123 Phone (858) 278-3600 wsp.com

M

AT

C H

LI

N

E

+5

M

AT

C H

LI

N

E

+5

LEGEND

Approximate Boring LocationBH1

Inferred Approximate Depth to Bedrock (Highly Weathered Rock) Based on Topography

Depth to Bedrock (Highly Weathered Rock) at Boring Location

1'

6'

Artificial FillQaf Cole Grade TonaliteKt Approximate Geologic Contact

6,082' to Cool

APPENDIX A

Field Investigation and Boring Logs

PRE-DRILLING ACTIVITIES

Traffic control, encroachment and excavation permits were obtained from the County Traffic

Division prior to drilling. Boring permits from the County of San Diego Department of

Environmental Health were not required because the borings were not expected to exceed a depth of 20 feet or encounter groundwater. WSP subconsultant Atlas Geophysics was retained to provide private utility screening services. As required by law, Dig Alert was notified at least three working days before drilling to locate buried utilities in the vicinity of the proposed borings.

EXPLORATORY BORINGS

Three exploratory borings extending to depths ranging from 5.5 feet to 10 feet were drilled at the approximate locations indicated on Plates 1 through 3. The borings were drilled with a truck-mounted Marl M10 hollow-stem auger rig operated by Pacific Drilling of San Diego, California.

The borings were drilled to obtain samples for laboratory testing and subsurface information to aid in pavement design.

Prior to drilling, each boring location was hand augered to refusal (generally about 2 feet) to reduce the risk of damage to utilities. As drilling progressed, soil and rock samples were then collected from each boring at selected depth intervals using a California-Modified sampler.

Vertical sample intervals were typically 2.5 feet to 5 feet. Bulk samples of the surface soils were also retrieved directly from the auger cuttings.

A California Modified sampler was driven using a 140-pound automatic hammer falling 30 inches.

The number of hammer blows required to drive the samplers for each 6-inch interval of the 18-inch drive is termed the blow count and is recorded on the boring logs. If effective sampler refusal

(50 blows for less than 6 inches) was met before the full 18-inch drive was completed, the drive was terminated, and the blow count and the driven distance recorded. Blow counts presented on the boring logs are as recorded in the field and are not corrected for sampler type, depth, or other factors. Field descriptions have been modified where appropriate to reflect the findings of our laboratory tests and granular material densities based on blow counts (N-values) corrected for drill rig efficiencies.

Soils encountered were visually classified in the field in general accordance with the Unified Soil

Classification System and ASTM D 2487. Soil and rock samples were transported to the WSP laboratory for further examination and testing to evaluate the engineering properties of encountered materials.

SUBSURFACE EXPLORATION LEGEND

UNIFIED SOIL CLASSIFICATION CHART

SOIL DESCRIPTION GROUP

SYMBOL

TYPICAL NAMES

I. COARSE GRAINED, more than half of material is larger than No. 200 sieve size.

GRAVELS CLEAN GRAVELS GW Well graded gravels, gravel-sand mixtures, little or no fines.

More than half of coarse fraction is larger than No. 4 sieve size, but smaller than 3”.

GP Poorly graded gravels, gravel-sand mixtures, little or no fines.

GRAVELS WITH FINES

(Appreciable amount of fines)

GM Silty gravels, poorly graded gravel-sand mixtures.

GC Clayey gravels, poorly graded gravel-sand, clay mixtures

SANDS CLEAN SANDS SW Well graded sand, gravelly sands, little or no fines

More than half of coarse fraction is smaller than No. 4 sieve size.

SP Poorly graded sands, gravelly sands, little or no fines

SANDS WITH FINES SM Silty sands, poorly graded sand and silty mixtures.

(Appreciable amount of fines)

SC Clayey sands, poorly graded sand and clay mixtures.

II. FINE GRAINED, more than half of material is smaller than No. 200 sieve size.

SILTS AND CLAYS

Liquid Limit less than 50

ML Inorganic silts and very fine sands, rock flour, sandy silt or clayey-silt-sand mixtures with slight plasticity

CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays

OL Organic silts and organic silty clays or low plasticity

SILTS AND CLAYS

Liquid Limit less than 50

MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts.

CH Inorganic clays of high plasticity, fat clays

OH Organic clays of medium to high plasticity

III. HIGHLY ORGANIC SOILS PT Peat and other highly organic soils.

– Water level at time of excavation or as indicated

CAL – California Modified Ring Sample PI – Plasticity Index

SPT – Standard Penetration Test Sample RC – Relative Compaction

CK – Chunk sample RV – R-Value

BK – Bulk sample SA – Sieve Analysis

NR – No recovery SC – Sand Cone

AL – Atterberg Limits SPT – Standard Penetration Sample

CON – Consolidation ST – Shelby Tube

COR Corrosion (pH, resistivity, sulfates, chlorides) TX – Triaxial Compression

DS – Direct Shear UC – Unconfined Compression

EI – Expansion Index

MAX – Maximum Density

MD – Moisture & Density

MS – Maximum Size of Particle

COLE GRADE ROAD IMPROVEMENTS

BY: MF DATE: 7-16-24

PROJECT NO: 5015-18-0024.20 PLATE: A1

Date Drilled:

Drill Rig: Logged by:

Driller: Surface Elevation (ft, msl):

Hammer Type/Weight/Drop: Depth to Water (ft):

Surface Material:

U S

C S

D R

IV

E

S A

M P

L E

B U

L K

P E

N E

T R

A T

IO

N

(b lo w s ft o f d ri v e

M O

IS

T

U R

E

D R

Y U

N

IT

W T

(p c f)

SC

5.1 133.4

BY: MF DATE:

PROJECT NO: 5015-16-0024.20 A2

Soil (NB Shoulder)

TONALITE - Fine- to medium-grained, massive, off-white to tan, highly weathered, extremely weak, friable

7/15/2024

COLE GRADE ROAD IMPROVEMENTS

PLATE:

LOG OF BORING BH1

D

E P

T H ft

E L

E V

A T

IO

N ft m s l)

SUMMARY OF SUBSURFACE CONDITIONS

SAMPLES

MARL M10

Toby Clark 1,533

Pacific Drilling

L A

B O

R A

T O

R Y

T E

S T

S

RV

Auto / 140 lb / 30 inches

6/12/2024

M. Farr

Drilling Contractor:

N/A

SLOPEWASH/RESIDUAL SOIL - Light reddish-brown, dry, medium dense, fine-grained CLAYEY SAND

1,530

CAL

MD

1,525

BK

Bottom of boring at 6'

Hand augered to about 2'

CAL

50/5"

1234567891

Driller: Surface Elevation (ft, msl):

Hammer Type/Weight/Drop: Depth to Water (ft):

Surface Material:

U S

C S

D R

IV

E

S A

M P

L E

B U

L K

P E

N E

T R

A T

IO

N

(b lo w s ft o f d ri v e

M O

IS

T

U R

E

D R

Y U

N

IT

W T

(p c f)

SM&

SC

CAL

SC/

CL

BK 13.5 119.0

12.0 126.7

8.9 123.3

BY: MF DATE:

PROJECT NO: 5015-16-0024.20 A3

7/15/2024

COLE GRADE ROAD IMPROVEMENTS

PLATE:

Bottom of boring at 10'

Hand augered to about 2'

LOG OF BORING BH2

D

E P

T H ft

E L

E V

A T

IO

N ft m s l)

SUMMARY OF SUBSURFACE CONDITIONS

SAMPLES

MARL M10

Toby Clark 1,490

Pacific Drilling

L A

B O

R A

T O

R Y

T E

S T

S

Auto / 140 lb / 30 inches

6/12/2024

M. Farr

Drilling Contractor:

N/A

AC (SB Shoulder)

8" AC over 6" Aggregate Base

TONALITE - Fine- to medium-grained, massive, reddish-brown (mottled), highly weathered, extremely weak, friable

1,485

SA,

RV, EI

MD

50/5"

MD

SA, EI,

MD

1,480

CAL

CAL

BK

SLOPEWASH/RESIDUAL SOIL - Dark reddish-brown (mottled), moist, medium dense, fine-grained CLAYEY SAND/SANDY CLAY

ARTIFICIAL FILL - Dark reddish-brown, moist, loose to medium dense, fine- to medium-grained, CLAYEY SAND and SILTY SAND; micaceous, occasional layers of SANDY CLAY

Driller: Surface Elevation (ft, msl):

Hammer Type/Weight/Drop: Depth to Water (ft):

Surface Material:

U S

C S

D R

IV

E

S A

M P

L E

B U

L K

P E

N E

T R

A T

IO

N

(b lo w s ft o f d ri v e

M O

IS

T

U R

E

D R

Y U

N

IT

W T

(p c f)

SM

SM

4.9 136.7

CAL

BY: MF DATE:

PROJECT NO: 5015-16-0024.20 A4

7/15/2024

COLE GRADE ROAD IMPROVEMENTS

50/6"

PLATE:

LOG OF BORING BH3

D

E P

T H ft

E L

E V

A T

IO

N ft m s l)

SUMMARY OF SUBSURFACE CONDITIONS

SAMPLES

MARL M10

Toby Clark 1,492

Pacific Drilling

L A

B O

R A

T O

R Y

T E

S T

S

6/12/2024

M. Farr

Drilling Contractor:

N/A

Soil (SB Shoulder)

TONALITE - Fine- to medium-grained, massive, light reddish-brown, highly weathered, very weak, friable, mica-rich

SA,

RV, EI

Auto / 140 lb / 30 inches

BK

ARTIFICIAL FILL - Reddish-brown, damp, loose to medium dense, fine- to coarse-grained SILTY SAND

SLOPEWASH/RESIDUAL SOIL - Reddish-brown, damp, medium dense, fine- to medium-grained SILTY SAND

MD

1,490

1,485

Bottom of boring at 5.5'

Hand augered to about 2'

CAL

50/2"

APPENDIX B

Laboratory Testing

GENERAL

Laboratory tests were performed on selected soil and rock samples to evaluate engineering characteristics of the various earth materials encountered. Testing was performed in accordance with one of the following references:

1) ASTM standards for soil testing, latest revisions.

2) State of California Department of Transportation (Caltrans) standard test methods, latest revisions.

A summary of the test results is presented on Plate B1. Test results for the various individual test are presented on Plates B2 through B11. A description of our laboratory testing program is provided below.

CLASSIFICATION

Soils were visually and texturally classified in accordance with the Unified Soil Classification

System (USCS) in general accordance with ASTM D2487. Soil and rock classifications are indicated on the boring logs presented in Appendix A.

GRAIN SIZE ANALYSIS

Grain size analyses were performed on representative soil samples to evaluate the gradation characteristics of the soil and to aid in classification. The tests were performed in general accordance with ASTM D1140/D6913. Test results are presented on Plates B2 through B4.

IN-SITU MOISTURE AND DENSITY

Natural moisture contents and dry density tests were performed on intact soil and rock samples.

Moisture content was evaluated in general accordance with ASTM D2216, while dry unit weight was evaluated using procedures similar to ASTM D2937. The results are presented on the boring logs presented in Appendix A and on Plate B5.

R-VALUE

R-Value tests were performed on representative soil samples to evaluate the strength of the soils to support traffic loads and to aid in pavement design. R-Value was evaluated in general accordance with ASTM D2844/CTM 301. The results are presented on Plates B6 through B8.

EXPANSION INDEX

Expansion index tests were performed on representative soil samples to evaluate their expansion potential. Expansion index was evaluated in general accordance with ASTM D4829. Test results are presented on Plates B9 through B11.

Plate B1

WSP USA Environment & Infrastructure Inc.

9177 Sky Park Ct. San Diego, CA. 92123

PHYSICAL PROPERTIES OF SOILS

PROJECT: Cole Grade Road LAB NO.: 36929-31 & 36973-82 PROJECT NO.: 5015-18-0024.20

SAMPLED BY: MF/BS DATE: 6/4-5/2024

CLIENT: County of SD - DPW SUBMITTED BY: M. Farr DATE: 6/6/2024

AUTHORIZED BY: M. Farr DATE: 6/20/2024

REVIEWED BY: M. Gibson REPORT DATE: 7/12/2024

WSP Lab

No.

Boring Depth

(ft.)

-#200, %

(ASTM

D1140)

As-Received

Moisture

Content, %

(ASTM

D2216)

Dry

Density

(pcf)

R-Value

(ASTM

D2844)

Expansion

Index (ASTM

D4829)

36929 BH1 0-2 * * * 38 *

36973 BH1 3-3.5 * 5.1 133.4 * *

36930 BH2 14”-36” 37.2 * * 28 28 (Low)

36977 BH2 3-3.5 48.1 * * * 38 (Low)

36978 BH2 3-3.5 * 13.5 119.0 * *

36979 BH2 5-5.5 * 12.0 126.7 * *

36981 BH2 9-9.5 * 8.9** 123.3** * *

36931 BH3 0-2 16.2 * * 65 1 (Very Low)

36982 BH3 2.5-3 * 4.9 136.7 * *

Notes: *Indicates test not assigned.

**Sample #36981 had coarse particles (1/2" or 3/4" by 2" in size) observed, removed and not used in the moisture/density reported.

Coarse Coarse Medium Fine

0.0 1.1 3.0 15.7 42.1

Sieve No.

Opening

(mm)

Percent

Finer Sieve No.

Opening

(mm)

Percent

Finer

3 in. 75.0 100 No. 4 4.75 98

2.5 in. 63.0 100 No. 10 2.00 95 Lab No.: 36930

2 in. 50.0 100 No. 20 0.85 90

1.5 in. 38.1 100 No. 40 0.425 79

1 in. 25.0 100 No. 60 0.250 67

3/4 in. 19.0 100 No. 100 0.150 53 Sample/Boring Number: BH2

1/2 in. 12.7 99 No. 140 0.106 43 Depth: 14"-36"

3/8 in. 9.5 98 No. 200 0.075 37

PL= LL=

Date Sampled: 6/4-5/2024 PI=

Date Tested: 6/26/2024 D90 = 0.9332 D85 = 0.6600

Tested By: CC D60 = 0.2029 D50 = 0.1381

Checked By: M. Gibson D30 = N/A D15 = N/A

D10 = N/A

CU = N/A Cc = N/A

SD County - DPW

Cole Grade Road

5015180024.20

Plate B2

(858)278-3600

37.2

Remarks

Client:

Project:

Project No.:9177 Sky Park Court, San Diego, CA 92123

Coefficients

Particle Size Distribution Report

%+3"

Material Description

Atterberg Limits

Clayey Sand, SC

% GRAVEL % SAND % FINES

Fine

1.0

Silt and Clay

ASTM D6913

i n

.5 i n i n

.5 i n i n

/4 i n

/2 i n

/8 i n

N o

N o

N o

N o

N o

N o

N o

N o

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0010.010.1110100

P e rc e n t P a ss in g

Particle Size -mm

COARSE FINE COARSE MEDIUM FINE

SILT

GRAVEL SAND

CLAY

0.0 0.0 1.8 11.5 38.5

Sieve No.

Opening

(mm)

Percent

Finer Sieve No.

Opening

(mm)

Percent

Finer

3 in. 75.0 100 No. 4 4.75 100

2.5 in. 63.0 100 No. 10 2.00 98 Lab No.: 36977

2 in. 50.0 100 No. 20 0.85 94

1.5 in. 38.1 100 No. 40 0.425 87

1 in. 25.0 100 No. 60 0.250 76

3/4 in. 19.0 100 No. 100 0.150 63 Sample/Boring Number: BH2

1/2 in. 12.7 100 No. 140 0.106 54 Depth: 3.0'-3.5'

3/8 in. 9.5 100 No. 200 0.075 48

PL= LL=

Date Sampled: 6/4-5/2024 PI=

Date Tested: 7/3/2024 D90 = 0.6121 D85 = 0.3985

Tested By: CC D60 = 0.1349 D50 = 0.0850

Checked By: M. Gibson D30 = N/A D15 = N/A

D10 = N/A

CU = N/A Cc = N/A

SD County - DPW

Cole Grade Road

5015180024.20

Plate B3

(858)278-3600

48.1

Remarks

Client:

Project:

Project No.:9177 Sky Park Court, San Diego, CA 92123

Coefficients

Particle Size Distribution Report

%+3"

Material Description

Atterberg Limits

Clayey Sand, SC

% GRAVEL % SAND % FINES

Fine

0.0

Silt and Clay

ASTM D6913

i n

.5 i n i n

.5 i n i n

/4 i n

/2 i n

/8 i n

N o

N o

N o

N o

N o

N o

N o

N o

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0010.010.1110100

P e rc e n t P a ss in g

Particle Size -mm

COARSE FINE COARSE MEDIUM FINE

SILT

0.0 0.7 9.2 30.0 39.0

Sieve No.

Opening

(mm)

Percent

Finer Sieve No.

Opening

(mm)

Percent

Finer

3 in. 75.0 100 No. 4 4.75 94

2.5 in. 63.0 100 No. 10 2.00 85 Lab No.: 36931

2 in. 50.0 100 No. 20 0.85 71

1.5 in. 38.1 100 No. 40 0.425 55

1 in. 25.0 100 No. 60 0.250 41

3/4 in. 19.0 100 No. 100 0.150 28 Sample/Boring Number: BH3

1/2 in. 12.7 99 No. 140 0.106 21 Depth: 0-2'

3/8 in. 9.5 98 No. 200 0.075 16

PL= LL=

Date Sampled: 6/4-5/2024 PI=

Date Tested: 6/26/2024 D90 = 3.4465 D85 = 1.9859

Tested By: CC D60 = 0.5504 D50 = 0.3598

Checked By: M. Gibson D30 = 0.1620 D15 = N/A

D10 = N/A

CU = N/A Cc = N/A

SD County - DPW

Cole Grade Road

5015180024.20

Plate B4

(858)278-3600

16.2

Remarks

Client:

Project:

Project No.:9177 Sky Park Court, San Diego, CA 92123

Coefficients

Particle Size Distribution Report

%+3"

Material Description

Atterberg Limits

Silty Sand, SM

% GRAVEL % SAND % FINES

Fine

4.9

Silt and Clay

ASTM D6913

i n

.5 i n i n

.5 i n i n

/4 i n

/2 i n

/8 i n

N o

N o

N o

N o

N o

N o

N o

N o

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

0.0010.010.1110100

P e rc e n t P a ss in g

Particle Size -mm

COARSE FINE COARSE MEDIUM FINE

SILT

WSP Environment & Infrastructure Inc.

Moisture & Density of ASTM Rings 9177 Sky Park Court, San Diego, CA

Lab # 36973 36978 36979 36981* 36982

Boring # BH1 BH2 BH2 BH2 BH3

Depth 3.0'-3.5' 3.0'-3.5' 5.0'-5.5' 9.0'-9.5' 2.5'-3.0'

Soil Type

Gray & White

Highly

Weathered

Rock with Silt

Dark Brown

Silty Sand, SM

Dark

Brown

Silty

Sand, SM

Light

Brown

Highly

Cement ed

Dark Gray

& Brown

Highly

Weathered

Rock

Wt. Soil + Ring 641.44 611.57 650.54 621.98 672.17

Wt. Ring 134.83 127.03 136.45 135.46 156.88

Wt. of Soil 506.61 484.54 514.09 486.52 515.29

Wet + Pan 585.50 565.82 593.61 567.52 586.17

Dry + Pan 561.03 508.31 538.65 527.66 562.52

Pan Wt. 80.12 81.90 81.12 81.98 76.34

Dia 1 2.42 2.41 2.42 2.42 2.42

Dia 2 2.42 2.41 2.42 2.42 2.42

Dia 3 2.42 2.41 2.42 2.42 2.39

Ht 1 0.99 1.00 1.00 1.00 1.00

Ht 2 1.00 1.00 1.01 1.00 1.01

Ht 3 1.00 1.00 1.00 1.01 1.00

Volume of Rings 0.00796 0.00791 0.00799 0.00799 0.00793

Moisture Content 5.1 13.5 12.0 8.9 4.9

Wet Density, pcf 140.2 135.1 141.9 134.3 143.3

Dry Density, pcf 133.4 119.0 126.7 123.3 136.7

*Sample #36981 had coarse particles (1/2" or 3/4" by 2" in size) observed, removed and not used in the moisture/density reported

Project: Cole Grade Rd.

Project #: 5015180024.20 Tested By: JB Date Tested: 6/26-27/2024

Plate B5

6/4-5/2024 by MF/BSSampled:

9177 Sky Park Court, San Diego, CA 92123

A B C

12.1 11.2 10.4

1280 1270 1279

125.8 126.9 130.8

170 200 200

199 262 457

2.59 2.59 2.41

-0.012 -0.009 -0.003

128 90 43

4.53 4.43 4.12

13 33 60

38 R-Value By Expansion: 100

Plate B6

Specimen

R-Value:

Exudation R-Value (Corrected)

R-Value By Exudation:

Moisture Content (%)

Wet Weight (g)

Compaction Pressure (psi)

Exudation Pressure (psi)

Height of Sample (in)

Expansion Pressure (psi)

Horiz. Pressure @ 2,000 lbs

Turns Displacement

Dry Density (pcf)

SD County DPW - Cole Grade

Road

PROJECT:

PROJECT NO.: 5015-18-0024.20

CLIENT:

LOCATION:

MATERIAL:

RESISTANCE R-VALUE OF TREATED & UNTREATED SOILS &

AGGREGATES (ASTM D2844/CALTRANS CTM301)

SOURCE: TEST METHOD:

Silty Sand, SM

BH-1 @0-2'

BLSD County DPW

SAMPLED BY:

SAMPLE DATE:

TESTED BY:

TEST DATE:

MF/BS

6/4-5/2024

MG

CTM 301

36929LAB NO.:

REVIEWED BY:

6/18/2024

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0.00 0.50 1.00 1.50 2.00 2.50 3.00

C o v e r T h ic k n e ss b y

E x p a n si o n

Cover Thickness by Stabilometer

EXPANSION CHART

0100200300400500600700800

R -v a lu e

Exudation Pressure (psi)

EXUDATION CHART

A B C

11.6 10.9 10.3

1260 1252 1245

128.7 131.3 132.0

140 140 140

209 311 629

2.51 2.46 2.41

0 0 0.039

134 94 70

3.91 4.06 3.80

11 30 44

28 R-Value By Expansion: 100

Plate B7

Specimen

R-Value:

Exudation R-Value (Corrected)

R-Value By Exudation:

Moisture Content (%)

Wet Weight (g)

Compaction Pressure (psi)

Exudation Pressure (psi)

Height of Sample (in)

Expansion Pressure (psi)

Horiz. Pressure @ 2,000 lbs

Turns Displacement

Dry Density (pcf)

SD County DPW - Cole Grade

Road

PROJECT:

PROJECT NO.: 5015-18-0024.20

CLIENT:

LOCATION:

MATERIAL:

RESISTANCE R-VALUE OF TREATED & UNTREATED SOILS &

AGGREGATES (ASTM D2844/CALTRANS CTM301)

SOURCE: TEST METHOD:

Clayey Sand, SC

BH-2 @14"-36"

BLSD County DPW

SAMPLED BY:

SAMPLE DATE:

TESTED BY:

TEST DATE:

MF/BS

6/4-5/2024

MG

CTM 301

36930LAB NO.:

REVIEWED BY:

6/19/2024

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0.00 0.50 1.00 1.50 2.00 2.50 3.00

C o v e r T h ic k n e ss b y

E x p a n si o n

Cover Thickness by Stabilometer

EXPANSION CHART

0100200300400500600700800

R -v a lu e

A B C

7.8 8.7 9.4

1242 1252 1260

131.1 132.2 129.7

350 350 350

478 358 171

2.45 2.42 2.51

0.12 0.087 0.06

25 34 55

3.94 3.8 4.80

76 70 50

65 R-Value By Expansion: 91

Plate B8

Specimen

R-Value:

Exudation R-Value (Corrected)

R-Value By Exudation:

Moisture Content (%)

Wet Weight (g)

Compaction Pressure (psi)

Exudation Pressure (psi)

Height of Sample (in)

Expansion Pressure (psi)

Horiz. Pressure @ 2,000 lbs

Turns Displacement

Dry Density (pcf)

SD County DPW - Cole Grade

Road

PROJECT:

PROJECT NO.: 5015-18-0024.20

CLIENT:

LOCATION:

MATERIAL:

RESISTANCE R-VALUE OF TREATED & UNTREATED SOILS &

AGGREGATES (ASTM D2844/CALTRANS CTM301)

SOURCE: TEST METHOD:

Silty Sand, SM

BH-3 @0-2'

BLSD County DPW

SAMPLED BY:

SAMPLE DATE:

TESTED BY:

TEST DATE:

MF/BS

6/4-5/2024

MG

CTM 301

36931LAB NO.:

REVIEWED BY:

6/17/2024

0.00

0.50

1.00

1.50

2.00

2.50

3.00

0.00 0.50 1.00 1.50 2.00 2.50 3.00

C o v e r T h ic k n e ss b y

E x p a n si o n

Cover Thickness by Stabilometer

EXPANSION CHART

0100200300400500600700800

R -v a lu e

2.1

Mass of test load applied, g: 5685.8

Wet weight + tare, g: 269.8 Wet weight + tare, g: 529.8

Dry weight + tare, g: 257.0 Dry weight + tare, g: 469.3

Tare weight, g: 80.3 Tare weight, g: 75.8

Initial moisture, %: 7.2 Final moisture, %: 15.4

621.9 4.011

192.2 1.001

429.7 0.0073196

1.013

1.043 457.4

130.1 132.2

121.3 114.6

50.3 88.2

0.774 in 28

0.802 in Low

0.028 in

Plate B9

Test duration, hours:

Final reading:

Initial reading:

Difference:

Final soil mass, g:

Expansion Index:

Degree of saturation, %:

After Test Density and Saturation

Wet density of soil, pcf:

Dry density of soil, pcf:

Degree of saturation, %:

Ring height (in):

Ring diameter (in):

Dry density of soil, pcf:

Wet density of soil, pcf:

As-Tested Density and Saturation

Initial height of sample measured, in.:

Final height of sample measured, in.:

Weight compacted sample, g:

Weight of ring, g:

Weight of soil, g: Ring volume (cubic feet):

Prior to Testing Moisture Content After Testing Moisture Content

Sample Amount Retained on #4 Sieve, %:

BH2 @ 14"-36"

Clayey Sand, SC

Tested By:

Reviewed By:

Soil Type:

Sample Location:

Project Name:

C. Corbala Date Tested: 6/28/2024

M. Gibson Date Reviewed: 7/9/2024

Expansion Index - ASTM D4829

Phone: 858-278-3600 Fax: 858-278-5300

9177 Sky Park Court, San Diego, CA 92123

MF/BS Date Sampled: 6/4-5/2024

SD County DPW - Cole Grade Road

5015-18-0024.20 Lab #: 36930Project #:

Sampled By:

2.9

Wet weight + tare, g: 214.7 Wet weight + tare, g: 533.0

Dry weight + tare, g: 205.0 Dry weight + tare, g: 466.8

Tare weight, g: 78.4 Tare weight, g: 76.1

Initial moisture, %: 7.7 Final moisture, %: 16.9

627.9 4.009

200.3 1.000

427.6 0.0073050

1.01

1.065 458.4

129.5 129.9

120.3 111.1

51.5 88.4

0.966 in 38

1.004 in Low

0.038 in

Plate B10

Test duration, hours:

Final reading:

Initial reading:

Difference:

Final soil mass, g:

Expansion Index:

Degree of saturation, %:

After Test Density and Saturation

Wet density of soil, pcf:

Dry density of soil, pcf:

Degree of saturation, %:

Ring height (in):

Ring diameter (in):

Dry density of soil, pcf:

Wet density of soil, pcf:

As-Tested Density and Saturation

Initial height of sample measured, in.:

Final height of sample measured, in.:

Weight compacted sample, g:

Weight of ring, g:

Weight of soil, g: Ring volume (cubic feet):

Prior to Testing Moisture Content After Testing Moisture Content

Sample Amount Retained on #4 Sieve, %:

BH2 @ 3'-3.5'

Clayey Sand, SC

Tested By:

Reviewed By:

Soil Type:

Sample Location:

Project Name:

C. Corbala Date Tested: 7/1/2024

M. Gibson Date Reviewed: 7/9/2024

Expansion Index - ASTM D4829

Phone: 858-278-3600 Fax: 858-278-5300

9177 Sky Park Court, San Diego, CA 92123

MF/BS Date Sampled: 6/4-5/2024

SD County DPW - Cole Grade Road

5015-18-0024.20 Lab #: 36977Project #:

Sampled By:

5.6

Wet weight + tare, g: 268.9 Wet weight + tare, g: 515.1

Dry weight + tare, g: 255.8 Dry weight + tare, g: 465.0

Tare weight, g: 78.6 Tare weight, g: 79.9

Initial moisture, %: 7.4 Final moisture, %: 13.0

617 4.007

191.1 1.001

425.9 0.0073050

1.019

1.035 438.7

129.0 128.0

120.1 113.3

49.5 72.0

0.970 in 1

0.969 in Very Low

0.001 in

Plate B11

Expansion Index - ASTM D4829

Phone: 858-278-3600 Fax: 858-278-5300

9177 Sky Park Court, San Diego, CA 92123

MF/BS Date Sampled: 6/4-5/2024

SD County DPW - Cole Grade Road

5015-18-0024.20 Lab #: 36931Project #:

Sampled By:

C. Corbala Date Tested: 6/28/2024

M. Gibson Date Reviewed: 7/9/2024

Tested By:

Reviewed By:

Soil Type:

Sample Location:

Project Name:

Prior to Testing Moisture Content After Testing Moisture Content

Sample Amount Retained on #4 Sieve, %:

BH3 @ 0-2'

Silty Sand, SM

Ring height (in):

Ring diameter (in):

Dry density of soil, pcf:

Wet density of soil, pcf:

As-Tested Density and Saturation

Initial height of sample measured, in.:

Final height of sample measured, in.:

Weight compacted sample, g:

Weight of ring, g:

Weight of soil, g: Ring volume (cubic feet):

Test duration, hours:

Final reading:

Initial reading:

Difference:

Final soil mass, g:

Expansion Index:

Degree of saturation, %:

After Test Density and Saturation

Wet density of soil, pcf:

Dry density of soil, pcf:

Degree of saturation, %: