CA_FTFW_KERN_12(1),_900(1),_Trails(1)_100__FINAL_Pavement_Report.pdf

SUBMITTED TO:

HDR Engineering, Inc.

1670 Broadway, Suite 3400

Denver, Colorado 80202

BY:

Shannon & Wilson, Inc.

1321 Bannock St., Suite 200

Denver, Colorado 80204

(303) 825-3800 www.shannonwilson.com

PAVEMENT DESIGN REPORT

CA FTFW Kern 12(1), 900(1), Trails(1)

Kern National Wildlife Refuge

KERN COUNTY, CALIFORNIA

June 2019

Shannon & Wilson No: 102738-001

Pavement Design Report

102738-001 June 2019 ii

C O

N T

E N

T S

CONTENTS

1 Introduction

2 Project and Site Description

3 Subsurface Explorations and Laboratory Testing

3.1 Field Investigation

3.2 Geotechnical Laboratory Testing

4 Pavement Assessment

5 Regional Geology and Subsurface Conditions

5.1 Regional Geology

5.2 Ground Conditions

5.3 Groundwater

6 Pavement Recommendations

6.1 Design Methodology

6.2 Swelling Soil

6.3 Traffic Loading

6.4 Pulverized Full Depth Reclamation (FDR)

6.5 Subgrade Soils

6.6 Recommended Pavement Sections

7 Construction and Materials Specifications

7.1 Site Preparation

7.2 Earthwork

7.2.1 Subgrade Preparation

7.2.2 Fill Placement

7.2.3 Proof-Rolling

7.3 Paving Materials

7.4 Corrosion Testing

8 Closure

9 References

Exhibits

Exhibit 7-1: Recommended Materials for Pavements iii

C O

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Figures

Figure 1: Vicinity Map

Figure 2: Site and Exploration Plan

Appendices

Appendix A: Subsurface Explorations

Appendix B: Laboratory Test Results

Appendix C: Pavement Conditions and Site Photographs

Appendix D: Pavement Design Calculations

Important Information iv

A C

R O

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ACRONYMS

AASHTO American Association of State Highway and Transportation Officials

ACI American Concrete Institute

ASTM ASTM International

CALTRANS California State Department of Transportation

ESAL Equivalent Single Axle Loading

FDR Full Depth Reclamation

FHWA Federal Highway Administration

FWS U.S. Fish and Wildlife Services

HACP Hot Asphalt Concrete Pavement

HDR HDR Engineering, Inc.

LL Liquid Limit

NMAS Nominal Maximum Aggregate Size

PDDM Project Development and Design Manual

PG Performance Grade

PI Plastic Index

SPT Standard Penetration Test

USDOT U.S. Department of Transportation

UTBC Untreated Base Course

Pavement Design Report

102738-001 June 2019

1 INTRODUCTION

This report summarizes the results of our subsurface exploration and laboratory testing program and presents pavement design recommendations and construction considerations for the proposed Kern National Wildlife Refuge (Kern NWR) Project (the Project) in Kern

County, California. Our services were completed in general accordance with our Task

Order Agreement No. 009/1000100038962 with HDR Engineering, Inc. (HDR) dated March

15, 2019. Our conclusions and recommendations in this report are based on:

▪ The limitations of our approved scope, schedule, and budget described in our contract;

▪ Our understanding of the Project and information provided by HDR;

▪ Subsurface conditions observed in the borings at the time our explorations were completed; and

▪ The results of testing performed on samples collected from the explorations.

The objective of our geotechnical studies was to provide recommendations and construction considerations, as presented herein, for the proposed roadway reconstruction. The authorized scope of services was based on this objective and this report should not be used for other purposes without Shannon & Wilson, Inc.’s (Shannon & Wilson’s) review. If a service is not specifically indicated in this report, do not assume that it was performed.

2 PROJECT AND SITE DESCRIPTION

The Project is located in Kern County, California (Figure 1). The Kern NWR is accessed via the HQ Entrance Road (RTE 012) from the west off of Garces Highway. A headquarter building is accessed from the HQ Entrance Road and the HQ/VC Parking lot (RTE 900) is located along the HQ Entrance Road adjacent to the headquarter building. Directly surrounding the HQ Entrance Road is Kern and Goose Lake. The roadway is relatively flat throughout the Project alignment. The existing HQ Entrance Road is paved with hot asphalt concrete pavement (HACP) and consists of two lanes. Based on discussions with HDR, we understand the Project will include replacement of the existing pavement with new HACP and removal of an existing speed bump and replacement with a speed table. We understand that nominal grade changes and roadway widening may be included as part of the project. Refer to Figure 2 for a project map.

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102738-001 June 2019

3 SUBSURFACE EXPLORATIONS AND LABORATORY

TESTING

3.1 Field Investigation

Shannon & Wilson conducted a field exploration program on April 19, 2019, to explore subsurface conditions along the proposed roadway alignment. The subsurface exploration program consisted of drilling and sampling two borings (designated SW-01 and SW-02) along the HQ Entrance Road/RTE 012, as shown in Figure 2. The borings were advanced to a depth of 10.5 feet below the ground surface.

Appendix A presents a discussion of the drilling and sampling procedures used to complete the borings. Appendix A also presents the individual exploration logs and an explanation of the symbols and terminology used. Photographs of the drilling locations and existing pavement are included in Appendix C.

3.2 Geotechnical Laboratory Testing

Geotechnical laboratory tests were completed on selected samples retrieved from the borings to estimate index and engineering properties. Index tests included natural water content, fines content, and Atterberg limits. Engineering properties tests included corrosion and Hveem Stabilometer (R-value) tests. Laboratory test results and a discussion of the testing procedures are included in Appendix B. The natural water content, fines content, and Atterberg limits are also shown on the individual boring logs included in Appendix A.

4 PAVEMENT ASSESSMENT

To evaluate the condition of the existing roadway pavement for potential rehabilitation options, we performed a visual pavement survey to assess the overall pavement condition and to identify areas of distress and typical crack patterns. The U.S. Fish and Wildlife

Services (FWS) has developed a rating system to quantify levels of distress and to describe roadway conditions of asphalt pavements. Their five levels of pavement condition for asphalt are summarized below:

Asphalt

▪ Excellent: Recently constructed or overlaid road where construction or overlay was performed correctly. No maintenance required.

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102738-001 June 2019

▪ Good: Low extent longitudinal and transverse cracks. All cracks are ¼ inch or less with little or no crack erosion. Patches are in good condition and applied correctly. Routine maintenance recommended.

▪ Fair: Roads are in good structural condition with little or no fatigue cracking.

Longitudinal, transverse, and edge cracking is at medium extent and severity. Block cracking is extensive. Any patches are in good condition. Preventative maintenance recommended.

▪ Poor: Road beginning to show signs of structural distress. Fatigue cracking is medium to high extent and medium severity. Cracking will be severe. Surface may have severe block cracking and show. Patches are in fair to poor condition. There is moderate distortion or rutting and occasional potholes. Rehabilitation recommended.

▪ Failed: Road is severely deteriorated. Signs of structural failure appear along with severe and extensive fatigue cracking, distortion, potholes, or extensive patches in poor condition. Reconstruction recommended.

Using the FWS visual rating system, we conducted our assessment survey on April 19, 2019.

Site photographs 1 through 8 contain document the condition of the existing pavement and present typical distress patterns observed along the roadway. The age of the existing pavement is unknown. The HQ Entrance Road/RTE 012 was generally in poor condition.

We observed medium severity fatigue cracking in the HACP throughout the HQ Entrance

Road/ RTE 012, along with edge cracking. The HQ/VC ABA Parking (RTE 900 concrete parking pad) and HQ/VC parking lot (RTE 900) pavement is in fair and good condition, respectively, with occasional low severity cracking.

5 REGIONAL GEOLOGY AND SUBSURFACE

CONDITIONS

5.1 Regional Geology

Based on our review of the Geologic Map of California - Bakersfield sheet, the geology of the site consists of Quaternary Great Valley basin deposits (Smith, 1964).

5.2 Ground Conditions

The HACP pavement thickness was measured at each of the boring locations. The HACP ranged in thickness from 3 to 4 inches as measured in the two borings. Immediately below the pavement, the borings encountered about 6 inches of base course and then medium stiff clay with varying percentages of sand (American Association of State Highway and

Transportation Officials [AASHTO] soil classification A-7-6).

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Our observations are specific to the locations, depths, and dates noted on the exploration logs in Appendix A and may not be applicable to all areas of the site. There is no amount of explorations or laboratory testing that can precisely predict the characteristics, quality, or distribution of subsurface conditions at every location throughout the site. Variations in the subsurface conditions may occur between and below the borings. Also, the passage of time or intervening causes (natural and manmade) may result in changes to the conditions of the site and subsurface conditions.

5.3 Groundwater

Groundwater was not encountered in any of our borings, however, fluctuations of groundwater levels at the site are likely and will depend on many factors, including seasonal variations, local precipitation, and flood events. Groundwater is not anticipated to affect the design or construction of the Project.

6 PAVEMENT RECOMMENDATIONS

Performance of a pavement system depends on the pavement material and thicknesses, subgrade strength, traffic loads and repetitions, design life, and subgrade drainage characteristics. The following sections discuss each of these aspects as they relate to the project.

6.1 Design Methodology

Our pavement design and results are based on the design procedures presented in the

1993 AASHTO Guide for the Design of Pavement Structures with guidance from the U.S.

Department of Transportation and Federal Highway Administration (FHWA) Federal

Lands Highway Project Development and Design Manual (PDDM), dated March 2008.

Pavement design inputs and calculations are presented in Appendix D.

6.2 Swelling Soil

Certain soil formations in California are susceptible to volume change by swelling/shrinking. This geologic phenomenon has the potential to cause substantial damage to lightly loaded structures, such as pavements, when exposed to water. To provide an indication of the swell potential of near surface soils at the site, we performed

Atterberg limits, grain size distributions, and moisture contents on soil samples encountered in our explorations. Based on testing of subgrade samples from the project site, the Plastic

Index (PI) ranged from 32 to 55, and the Liquid Limit (LL) ranged from 45 to 69, however

Pavement Design Report

102738-001 June 2019 the near surface soils indicated a PI of 32 and a LL of 45. Section 11.3.2.1.3 of the PDDM specifies that 4 to 6 feet of moisture treatment is required for roadways with a PI greater than 35 and an LL greater than 60. For roadway subgrades with PIs from 25 to 35 and an LL from 50 to 60, which appears to exist below the pavement, the PDDM specifies 2 to 4 feet of moisture treatment. The PDDM does note that the subexcavation requirements should account for the traffic volume and project significance when selecting a subexcavation depth.

Based on the low traffic volume, project significance and soils encountered in our borings, we make the following comments. If the above-specified over-excavation is cost prohibitive, consideration could be given to simply scarifying to a depth of 8 inches, moisture conditioning, and proof rolling prior to placing the new pavement section, provided Central

Federal Lands is willing to accept a low risk of swell-related movement. In our opinion, the risk would be low because the alignment will be in the same location and the moisture regime is unlikely to change provided construction is phased such that the exposed subgrade is not allowed to dry out. If the construction phasing cannot be controlled, 2 feet of moisture treatment beneath the pavement section may be a reasonable alternative to the

PDDM subexcavation requirement to account for potential drying out during construction.

Regardless of the phasing, we recommend 2 feet of overexcavation in areas outside of the existing pavement footprint (i.e. in widening areas).

6.3 Traffic Loading

Based on discussions with HDR, traffic counts are not available for the roadway and that the roadway is classified as a low volume road. For design of the roadway, we assumed an equivalent single axle loading (ESAL) of 50,000 based on the minimum recommend ESAL in the PDDM.

6.4 Pulverized Full Depth Reclamation (FDR)

We understand that pulverized full depth reclamation (FDR) is being considered for rehabilitation of the existing roadway pavement sections. The process involves pulverizing and mixing the existing asphalt with the underlying layers to create a uniformly blended, homogeneous material that will be incorporated into the proposed pavement section as a base course. The benefit of the FDR process is that it allows the existing material to be recycled in place and eliminates the expense to export the material offsite. The requirements in the PDDM indicate a minimum R-value of 70 percent for the pulverized

FDR. In our opinion, a blended material of pulverized asphalt and base course will likely exceed this requirement. For our analysis, we assumed a resilient modulus of 32,000 pounds per square inch for the pulverized FDR.

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102738-001 June 2019

The PDDM also indicates that pulverized FDR can be utilized in roadway widening projects. The FDR process can accommodate approximately up to 2 feet of roadway widening with the pulverization process. Areas where the roadway is anticipated to be widened greater than 2 feet will require import fill or stockpiling and placing excess pulverized base course from other areas of the project.

6.5 Subgrade Soils

As discussed in Section 5.0, the subsurface explorations completed along the roadway primarily consisted of clays with varying percentages of sands (A-7-6). To estimate the strength of the subgrade materials, an R-value test was completed on a bulk sample from boring SW-01 resulting in an R-value of less than 5. Laboratory index testing indicated the bulk sample consisted of AASHTO classification A-7-6. For the design subgrade strength, we used an AASHTO correlation between R-Value and resilient modulus, which calculates a resilient modulus value of 3,775 pounds per square inch.

6.6 Recommended Pavement Sections

Using the PDDM procedures and the parameters outlined in Appendix D, we recommend the following pavement sections for the Project:

▪ 4.0 inches of HACP overlying 6 inches of untreated base course (UTBC)

▪ 4.0 inches of HACP overlying 6 inches of pulverized FDR

7 CONSTRUCTION AND MATERIALS SPECIFICATIONS

The applicability of the design parameters in Section 6.0 is contingent on good construction practice. Poor construction techniques may alter conditions from those upon which our recommendations are based, and therefore result in poor performance. Our analyses assumed that this project is constructed according to FP-14 U.S. Customary Units (U.S.

Department of Transportation [USDOT] and FHWA, 2014) construction standards. The following sections provide additional construction considerations for this project.

7.1 Site Preparation

In widening areas, we recommend that brush and other vegetation be cleared and roots and stumps be removed from all areas to be graded in accordance with FP-14 Sections 201 and

203. All surface and subsurface structures associated with current development of the site, including pavements, utility poles, fence poles, underground utilities and other deleterious

Pavement Design Report

102738-001 June 2019 material, should also be removed. Any existing surficial topsoil and soil containing visible organics should be stripped and removed from all areas.

7.2 Earthwork

7.2.1 Subgrade Preparation

Proper subgrade preparation is required for adequate pavement performance. The exposed subgrade should be treated to an appropriate depth as discussed in Section 6.2.

7.2.2 Fill Placement

The on-site soils can be reused; however, due to the potential expansive nature of the clay, it will be important to place overexcavated materials at a moisture content above the optimum moisture content to reduce the potential for swell. In this regard, cohesive soils (AASHTO

A-6 and A-7) should be moisture treated to 1 to 3 percent above optimum moisture content.

All subgrade material and fill should be compacted to a dense/firm and unyielding condition in accordance with FP-14 Section 204.11. On-site subgrade and fill materials should be compacted to at least 95 percent maximum density, as determined by AASHTO

T180 or T99, as presented in FP-14 Section 204. Fill should be placed in uniform, horizontal layers not exceeding 8 inches in loose thickness for heavy, self-propelled compactors, or

4 inches for hand-operated mechanical compactors. The appropriate lift thickness will depend on the Contractor’s equipment and the moisture content and quality of the fill material.

Below pavements, clean granular soils are not recommended (as there will be no natural drainage and this can form a bathtub effect that can exacerbate swell). If imported fill is required, we recommend that the material have a minimum fines content of 30 percent.

This material should also have a minimum R-Value of 5.

The subgrade and fill should not be allowed to dry out during overexcavation and placement or the potential for swell and the possible magnitude of swell will increase. This may require wetting and remixing exposed lifts at the beginning of each day.

7.2.3 Proof-Rolling

As discussed above, the subgrade should be prepared in accordance with FP-14 Section

204.11, which includes the use of compression-type rollers. While it is important to place clayey material above the optimum moisture content to control swell, material placed wet of optimum is prone to pumping and yielding from construction activities. This material can

Pavement Design Report

102738-001 June 2019 be difficult to pass a proof-roll. The Contractor will need to carefully control the movement of equipment around the site and minimize the passage of equipment over the overexcavated area. Even with these precautions, compaction of the material will be difficult and extra working time should be anticipated. Placement and compaction testing should be monitored on a full-time basis to assist in this process.

7.3 Paving Materials

The following exhibit summarizes our recommendations for pavement material selection.

All specification sections reference the FP-14 U.S. Customary Units, (USDOT and FHWA, 2014).

Exhibit 7-1: Recommended Materials for Pavements

Material Specification Additional Requirements/Comments

UTBC

(Aggregate Base)

Section 301 - Use Gradation C, D, or E

- CalTrans Specification: Division IV Section 26

Pulverized FDR Section 304 - Minimum R-value of 70

- Compact according to Section 204.11

HACP

(Asphalt Concrete)

Section 401 or 403 - Aggregate must meet requirements for ESAL values ranging from 300,000 to 3,000,000

- ½ inch or ¾ inch NMAS

- PG Binder: PG 64-10

- Gyratory Number (N): 50 or 75

- CalTrans Specification: Division V Section 39

NOTES:

ESAL = Equivalent Single Axle Loading; FDR = Full Depth Reclamation; HACP = Hot Asphalt Concrete Pavement; NMAS = Nominal Maximum Aggregate Size; PG = Performance Grade; UTBC = Untreated Base Course

In accordance with the FP-14 Section 401 and 403, we understand that California State

Department of Transportation (CALTRANS) material specifications should be used for

HACP. Regarding the asphalt binder for HACP, the PDDM requires SuperPave performance grade (PG) binders. The PG binders are chosen based on local weather and anticipated traffic level conditions. Using the PDDM guidelines, a minimum of 95 percent reliability is required in terms of binder performance. Using a binder within an appropriate temperature and traffic loading range allows for a higher strength and better durability, and improved cohesion will translate into improved long-term performance.

We recommend following guidance from the CalTrans Highway Design Manual (2016), which indicates that PG 64-10 is the regionally appropriate binder for the inland valley climatic region. Recommended lift thicknesses for the ½ inch nominal maximum aggregate size (NMAS) HACP are between 0.1 and 0.2 feet (1.2 and 2.4 inches) and between 0.2 and

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102738-001 June 2019

0.25 feet (2.4 and 3.0 inches) for the ¾ inch NMAS HACP (CalTrans, 2018). A tack coat should be placed between subsequent lifts.

7.4 Corrosion Testing

To assist in estimating the corrosion potential at the site, a sample was tested for pH, conductivity, chloride and water-soluble sulfate tests) in our Denver, Colorado, laboratory.

The results are presented in Table B-1 in Appendix B.

Based on classifications as defined by ACI-318-14 (American Concrete Institute [ACI], 2014), the resistivity test results indicate highly corrosive conditions.

The concentration of water-soluble sulfates measured in the sample was measured to be less than 0.01 percent by weight. Based on classifications as defined by the American Concrete

Institute ACI-318-14 (ACI, 2014), these test results suggest a negligible degree of sulfate attack on concrete exposed to site soils (exposure class S0).

8 CLOSURE

This report has been prepared for the exclusive use of HDR and Central Federal Lands

Highway Division for the purpose of providing pavement recommendations for the Kern

National Wildlife Refuge project. This pavement design report should not be used without our approval if any of the following occurs:

▪ Assumptions stated in this report have changed.

▪ Project details change or new information becomes available such that our analyses and recommendations may be affected.

▪ A substantial period of time has passed since the date of this report.

If any of these occur, we should be retained to review the applicability of our analyses and recommendations.

Within the limitations of scope, schedule and budget, the analyses, conclusions and recommendations presented in this report were prepared in accordance with generally accepted professional geotechnical and geological principles and practice in this area at the time this report was prepared. We make no other warranty, either express or implied.

Shannon & Wilson, Inc. has prepared “Important Information about Your Geotechnical

Report,” to assist you and others in understanding the use and limitations of our reports.

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9 REFERENCES

American Concrete Institute (ACI), 2014, Building code requirements for structural concrete and commentary, Farmington Hills, Mich., ACI 318-14.

American Association of State Highway and Transportation Officials (AASHTO), 1993, AASHTO guide for design of pavement structures: Washington, D.C., AASHTO, 2 v.

California Department of Transportation (CalTrans), 2016, Highway Design Manual 6th

Edition. Available from: http://www.dot.ca.gov/hq/oppd/hdm/hdmtoc.htm

California Department of Transportation (CalTrans), 2018, Standard Specifications, State of

California Department of Transportation. Available from:

http://ppmoe.dot.ca.gov/hq/esc/oe/construction_contract_standards/std_specs/201

8_StdSpecs/2018_StdSpecs.pdf

Smith, A.R., 1964, Geologic map of California : Bakersfield sheet: California Division of

Mines and Geology, scale 1:250,000.

U.S. Department of Transportation (USDOT), Federal Highway Administration (FHWA), 2008, Federal Lands Highway project development and design manual (PDDM):

U.S. Department of Transportation and Federal Highway Administration.

Available from: http://flh.fhwa.dot.gov/resources/manuals/pddm/.

U.S. Department of Transportation (USDOT), Federal Highway Administration, 2014, Federal standard specifications for construction of roads and bridges on Federal

Highway projects, FP-14 English Units: U.S. Department of Transportation and

Federal Highway Administration, available from http://flh.fhwa.dot.gov/resources/pse/specs/.

U.S. Fish and Wildlife Service (FWS). Road Inventory Program Rating System.

http://www.dot.ca.gov/hq/oppd/hdm/hdmtoc.htm http://ppmoe.dot.ca.gov/hq/esc/oe/construction_contract_standards/std_specs/2018_StdSpecs/2018_StdSpecs.pdf http://ppmoe.dot.ca.gov/hq/esc/oe/construction_contract_standards/std_specs/2018_StdSpecs/2018_StdSpecs.pdf https://ngmdb.usgs.gov/Prodesc/proddesc_477.htm http://flh.fhwa.dot.gov/resources/manuals/pddm/ http://flh.fhwa.dot.gov/resources/pse/specs/

Garces Highway t h

A v e n u e

C o r c o r a n

R o a d

PROJECT

LOCATION

Sacramento

CALIFORNIA

Project

Location

Los Angeles

San Francisco

Eureka

Bakersfield

VICINITY MAP

NOTE

June 2019

F i l e n a m e

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V i c i n i t y

M a p d w g

D a t e

L o g i n

J R

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0 2 4

Approximate Scale in Miles

CA FTFW Kern 10(3)

Kern National Wildlife Refuge

Kern County, California

102738-001

Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft

Bing Maps reprinted with permission from

Microsoft Corporation.

FIG. 1

© 2019 Microsoft Corporation © 2019 DigitalGlobe ©CNES (2019) Distribution Airbus DS

SW-01

SW-02

C o r c o r a n

R o a d

Headquarter Building

Goose Lake

HQ Entrance Road

Graces

Highway

Kern Lake

Tulare Basin Trailhead

HQ/VC Parking

Check Station Overflow Parking

(RTE 906)

Covey Trailhead

F i l e n a m e

J

L A

X i t e

P l a n d w g y o u t

F i g u r e

D t e o g i n

J R

S

FIG. 2

SITE AND EXPLORATION PLAN

June 2019

CA FTFW Kern 10(3)

Kern National Wildlife Refuge

Kern County, California

102738-001

200 400

Scale in Feet

NOTE

Bing Map Image adapted from aerial imagery provided by Autodesk Live Maps and Microsoft

Bing Maps reprinted with permission from

Microsoft Corporation.

SW-01

Boring Designation and

Approximate Location

LEGEND

CA FTFW KERN 12(1), 900(1), Trails(1)

6/5/2019-102738_AA A-i

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Appendix A: Subsurface Explorations

Appendix A

Subsurface Explorations

CONTENTS

A.1 Introduction ........................................................................................................................... A‐1

A.2 Explorations ........................................................................................................................... A‐1

A.2.1 Soil and Rock Classification System ...................................................................... A‐1

A.2.2 Standard Penetration Test (SPT) ............................................................................ A‐1

A.2.3 Bulk Sampling .......................................................................................................... A‐2

Figures Figure A‐1: Soil Description and Log Key

Figure A‐2: Log of Borings SW‐1 and SW‐2

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A.1 INTRODUCTION

Shannon & Wilson, Inc.’s (Shannon & Wilson’s) field exploration program was conducted on April 19, 2019, and consisted of drilling two borings designated SW‐01 and SW‐02 at the locations shown on Figure 2. Photographs of boring locations are provided in Appendix C.

The methods used to conduct the field exploration program are described below.

A.2 EXPLORATIONS

The borings were coordinated (including subcontractor coordination and utility locates) and observed by Shannon & Wilson. Individual boring logs are presented in Figure A‐2. These exploration logs represent our interpretation of the contents of the field logs and select results of laboratory testing. The borings were drilled by 2R Drilling of Chino, California

(under subcontract to Shannon & Wilson) using a truck‐mounted CME 75 drill rig. The borings were advanced to a depth of 10.5 feet. Borings SW‐01 and SW‐02 were advanced using 6‐inch diameter hollow‐stem‐auger drilling techniques. On completion of drilling, the borings were backfilled with cuttings and repairs to the existing pavement were made with cold‐patch asphalt.

A.2.1 Soil and Rock Classification System

During exploration, our representative collected samples and prepared field logs of the explorations. Soil classification for this project was based on ASTM International (ASTM)

Designation: D2487, Standard Practice for Classification of Soils for Engineering Purposes

(Unified Soil Classification System), and ASTM Designation: D2488, Standard Practice for

Description and Identification of Soils (Visual‐Manual Procedure). The Unified Soil

Classification System is summarized in Figure A‐1. In addition, samples were classified based on American Association of State Highway and Transportation Officials (AASHTO)

Designation M‐145, Standard Specification for Classification of Soils and Soil‐Aggregate

Mixtures for Highway Construction Purposes.

A.2.2 Standard Penetration Test (SPT)

Disturbed samples were obtained in the borings in general accordance with the Standard

Penetration Test (SPT) (ASTM Designation: D1586). The SPT consists of driving a 2‐inch outside diameter, 1.375‐inch inside diameter split‐spoon sampler a distance of 18 inches with a 140‐pound hammer free‐falling a distance of 30 inches. An automatic hammer system was used to advance the samplers. During sampling, the Shannon & Wilson field

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S representative recorded the number of blows for each 6‐inch increment of penetration and summed the blow counts for the last two 6‐inch increments. This sum is recorded as the penetration resistance number, or N‐value. If high penetration resistance prevented driving the total length of the sampler, the Shannon & Wilson field representative recorded the partial penetration depth and blow count. The N‐values provide a means for evaluating the relative density or compactness of cohesionless (granular) soils and consistency or stiffness of cohesive (fine‐grained) soils (see Figure A‐1). The raw N‐values are shown on the individual boring logs. Representative portions of the split‐spoon sample obtained in conjunction with the SPT were placed in a screw‐top plastic jar and transported to our laboratory.

A.2.3 Bulk Sampling

A bulk soil sample was obtained by collecting the drill cuttings from the upper 5 feet of each boring. Approximately 20 to 30 pounds of cuttings of each sample were placed in a plastic bag and transported to our laboratory for further analysis and testing.

Kern County, California

102738-001June 2019

COBBLES

GRAVEL

FINES

SAND

Sheet 1 of 3

S&W INORGANIC SOIL CONSTITUENT DEFINITIONS

CONSTITUENT2

COHESIONLESS SOILS

Silt, Lean Clay, Elastic Silt, or

Fat Clay 3

PERCENTAGES TERMS 1, 2

Trace

Few

Little

Some

Mostly

WELL AND BACKFILL SYMBOLS

Bentonite Cement Grout

Bentonite Grout

Bentonite Chips

Silica Sand

Perforated or Screened Casing

SHANNON & WILSON, INC.

SOIL DESCRIPTION

AND LOG KEY

Geotechnical and Environmental Consultants

Absence of moisture, dusty, dry to the touch

Damp but no visible water

Visible free water, from below water table

FIG. A-1

Shannon & Wilson, Inc. (S&W), uses a soil identification system modified from the Unified Soil Classification System (USCS). Elements of the USCS and other definitions are provided on this and the following pages. Soil descriptions are based on visual-manual procedures (ASTM D2488) and laboratory testing procedures (ASTM D2487), if performed.

STANDARD PENETRATION TEST (SPT)

SPECIFICATIONS

Hammer:

Sampler:

N-Value:

Dry

Moist

Wet

MOISTURE CONTENT TERMS

Modifying (Secondary)

Precedes major constituent

Major

Minor Follows major constituent

1All percentages are by weight of total specimen passing a 3-inch sieve.

2The order of terms is: Modifying Major with Minor.

3Determined based on behavior.

4Determined based on which constituent comprises a larger percentage.

5Whichever is the lesser constituent.

COARSE-GRAINED

SOILS

(less than 50% fines)1

NOTE: Penetration resistances (N-values) shown on boring logs are as recorded in the field and have not been corrected for hammer efficiency, overburden, or other factors.

PARTICLE SIZE DEFINITIONS

RELATIVE DENSITY / CONSISTENCY

Sand or Gravel 4

30% or more coarse-grained:

Sandy or Gravelly 4

More than 12% fine-grained:

Silty or Clayey 3

15% to 30% coarse-grained:

with Sand or with Gravel 4

30% or more total coarse-grained and lesser coarse-grained constituent is 15% or more:

with Sand or with Gravel 5

Very soft Soft Medium stiff Stiff Very stiff Hard

Very loose Loose Medium dense Dense Very dense

RELATIVE

DENSITY

FINE-GRAINED SOILS

(50% or more fines)1

COHESIVE SOILS

< 2 2 - 4 4 - 8

8 - 15 15 - 30

> 30

1Gravel, sand, and fines estimated by mass. Other constituents, such as organics, cobbles, and boulders, estimated by volume.

2Reprinted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual-Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org.

140 pounds with a 30-inch free fall.

Rope on 6- to 10-inch-diam. cathead 2-1/4 rope turns, > 100 rpm

NOTE: If automatic hammers are used, blow counts shown on boring logs should be adjusted to account for efficiency of hammer.

10 to 30 inches long Shoe I.D. = 1.375 inches Barrel I.D. = 1.5 inches Barrel O.D. = 2 inches

Sum blow counts for second and third 6-inch increments.

Refusal: 50 blows for 6 inches or less; 10 blows for 0 inches.

RELATIVE

CONSISTENCY

N, SPT,

BLOWS/FT.

5% to 12% fine-grained:

with Silt or with Clay 3

15% or more of a second coarse-grained constituent:

with Sand or with Gravel 5

< 5%

5 to 10%

15 to 25%

30 to 45%

50 to 100%

Surface Cement Seal

Asphalt or Cap

Slough

Inclinometer or Non-perforated Casing

Vibrating Wire Piezometer

N, SPT,

BLOWS/FT.

< 4 4 - 10

10 - 30 30 - 50

> 50

DESCRIPTION

< #200 (0.075 mm = 0.003 in.)

#200 to #40 (0.075 to 0.4 mm; 0.003 to 0.02 in.)

#40 to #10 (0.4 to 2 mm; 0.02 to 0.08 in.)

#10 to #4 (2 to 4.75 mm; 0.08 to 0.187 in.)

SIEVE NUMBER AND/OR APPROXIMATE SIZE

#4 to 3/4 in. (4.75 to 19 mm; 0.187 to 0.75 in.)

3/4 to 3 in. (19 to 76 mm)

3 to 12 in. (76 to 305 mm)

> 12 in. (305 mm)

Fine Coarse

Fine Medium Coarse

BOULDERS

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102738-001

Kern National Wildlife Refuge

Kern County, California

June 2019

Inorganic

FINE-GRAINED

SOILS

SM

Sands

Silty or Clayey Gravel

Silt; Silt with Sand or Gravel; Sandy or Gravelly Silt

Organic Silt or Clay; Organic Silt or Clay with Sand or Gravel; Sandy or Gravelly Organic Silt or Clay

HIGHLY-

ORGANIC SOILS

COARSE-

GRAINED

SOILS

GW

Geotechnical and Environmental Consultants

SHANNON & WILSON, INC.

(less than 5% fines)

PT

(more than 12% fines)

MH

SP

GP

GM

Silty or Clayey Sand

Silty Gravel; Silty Gravel with Sand

GC

SC

Inorganic

Organic

(more than 50% of coarse fraction retained on No. 4 sieve)

MAJOR DIVISIONS GROUP/GRAPHIC

SYMBOL

CH

OH

ML

CL

TYPICAL IDENTIFICATIONS

Gravel

Sand

Silty Sand; Silty Sand with Gravel

Clayey Sand; Clayey Sand with Gravel

Clayey Gravel; Clayey Gravel with Sand

Sheet 2 of 3

Gravels

Primarily organic matter, dark in color, and organic odor

SW

(more than 12% fines)

Silts and Clays

Silts and Clays

(more than 50% retained on No.

200 sieve)

(50% or more of coarse fraction passes the No. 4 sieve)

(liquid limit less than 50)

(liquid limit 50 or more)

Organic

(50% or more passes the No. 200 sieve)

SOIL DESCRIPTION

AND LOG KEY

Elastic Silt; Elastic Silt with Sand or Gravel; Sandy or Gravelly Elastic Silt

Fat Clay; Fat Clay with Sand or Gravel;

Sandy or Gravelly Fat Clay

Organic Silt or Clay; Organic Silt or Clay with Sand or Gravel; Sandy or Gravelly Organic Silt or Clay

Poorly Graded Sand; Poorly Graded Sand with Gravel

Well-Graded Sand; Well-Graded Sand with Gravel

Well-Graded Gravel; Well-Graded Gravel with Sand

Poorly Graded Gravel; Poorly Graded Gravel with Sand

Lean Clay; Lean Clay with Sand or Gravel; Sandy or Gravelly Lean Clay

Peat or other highly organic soils (see

ASTM D4427)

FIG. A-1

OL

(less than 5% fines)

NOTES

1. Dual symbols (symbols separated by a hyphen, i.e., SP-SM, Sand with

Silt) are used for soils with between 5% and 12% fines or when the liquid limit and plasticity index values plot in the CL-ML area of the plasticity chart. Graphics shown on the logs for these soil types are a combination of the two graphic symbols (e.g., SP and SM).

2. Borderline symbols (symbols separated by a slash, i.e., CL/ML, Lean Clay to Silt; SP-SM/SM, Sand with Silt to Silty Sand) indicate that the soil properties are close to the defining boundary between two groups.

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UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)

(Modified From USACE Tech Memo 3-357, ASTM D2487, and ASTM D2488)

NOTE: No. 4 size = 4.75 mm = 0.187 in.; No. 200 size = 0.075 mm = 0.003 in.

Kern National Wildlife Refuge

Kern County, California

June 2019

Angular

Subangular

Subrounded

Rounded

Flat

Elongated

Sharp edges and unpolished planar surfaces.

Similar to angular, but with rounded edges.

Nearly planar sides with well-rounded edges.

Smoothly curved sides with no edges.

Width/thickness ratio > 3.

Length/width ratio > 3.

Narrow range of grain sizes present or, within the range of grain sizes present, one or more sizes are missing (Gap Graded). Meets criteria in ASTM D2487, if tested.

Full range and even distribution of grain sizes present. Meets criteria in ASTM D2487, if tested.

Crumbles or breaks with handling or slight finger pressure Crumbles or breaks with considerable finger pressure Will not crumble or break with finger pressure

Weak

Moderate

Strong

VISUAL-MANUAL CRITERIA

A 1/8-in. thread cannot be rolled at any water content.

A thread can barely be rolled and a lump cannot be formed when drier than the plastic limit.

A thread is easy to roll and not much time is required to reach the plastic limit. The thread cannot be rerolled after reaching the plastic limit. A lump crumbles when drier than the plastic limit.

It take considerable time rolling and kneading to reach the plastic limit.

A thread can be rerolled several times after reaching the plastic limit. A lump can be formed without crumbling when drier than the plastic limit.

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants Sheet 3 of 3

Interbedded

Laminated

Fissured

Slickensided

Blocky

Lensed

Homogeneous

Alternating layers of varying material or color with layers at least 1/4-inch thick; singular: bed.

Alternating layers of varying material or color with layers less than 1/4-inch thick; singular:

lamination.

Breaks along definite planes or fractures with little resistance.

Fracture planes appear polished or glossy;

sometimes striated.

Cohesive soil that can be broken down into small angular lumps that resist further breakdown.

Inclusion of small pockets of different soils, such as small lenses of sand scattered through a mass of clay.

Same color and appearance throughout.

At Time of Drilling Diameter Elevation Feet Iron Oxide Gallons Horizontal Hollow Stem Auger Inside Diameter Inches Pounds Magnesium Oxide Millimeter Manganese Oxide Not Applicable or Not Available Nonplastic Outside Diameter Observation Well Pounds per Cubic Foot Photo-Ionization Detector Pressuremeter Test Parts per Million Pounds per Square Inch Polyvinyl Chloride Rotations per Minute Standard Penetration Test Unified Soil Classification System Unconfined Compressive Strength Vibrating Wire Piezometer Vertical Weight of Hammer Weight of Rods Weight

ATD

Diam.

Elev.

ft.

FeO gal.

Horiz.

HSA

I.D.

in.

lbs.

MgO mm

MnO

NA

NP

O.D.

OW

pcf

PID

PMT

ppm psi

PVC

rpm

SPT

USCS

qu

VWP

Vert.

WOH

WOR

Wt.

STRUCTURE TERMS1

SOIL DESCRIPTION

AND LOG KEY

1Reprinted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual-Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org.

2Adapted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual-Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org.

ACRONYMS AND ABBREVIATIONS

Poorly Graded

Well-Graded

Irregular patches of different colors.

Soil disturbance or mixing by plants or animals.

Nonsorted sediment; sand and gravel in silt and/or clay matrix.

Material brought to surface by drilling.

Material that caved from sides of borehole.

Disturbed texture, mix of strengths.

Mottled

Bioturbated

Diamict

Cuttings

Slough

Sheared

DESCRIPTION

Nonplastic

Low

Medium

High

ADDITIONAL TERMS

PLASTICITY2

CEMENTATION TERMS1

GRADATION TERMS

APPROX.

PLASITICTY

INDEX

RANGE

< 4

4 to 10

10 to 20

> 20

PARTICLE ANGULARITY AND SHAPE TERMS1

FIG. A-1

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-1

S -2

S -3

S -4

4 inches of asphalt over 6 inches of base course.

Medium stiff, gray brown, Lean Clay with Sand and Gravel (CL) to Sandy Lean Clay (CL); moist;

fine sand, sub-angular gravel.

[A-7-6]

Medium dense, yellow, Clayey Sand (SC); moist;

fine sand.

[A-7-6]

BOTOOM OF BORING

COMPLETED ON 04/19/2019

G ro un dw at er

N ot

E nc ou nt e re d D ur in g D ri lli ng

0.3

0.8

8.0

10.5

June 2019

Sample Not Recovered

Hole Diam.:

Rod Type.:

Hammer Type:

SHANNON & WILSON, INC.

10.5 ft.

FIG. A-2

S am pl es

NOTES

LOG OF BORING SW-01

8 in.

2"

Automatic

S ym bo l

Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual.

SOIL DESCRIPTION

1. Refer to Figures A-1 and A-2 for explanation of symbols, codes, abbreviations and definitions.

2. The stratification lines represent the approximate boundaries between soil types, and the transition may be gradual.

3. The discussion in the text of this report is necessary for a proper understanding of the nature of the subsurface materials.

4. Groundwater level, if indicated above, is for the date specified and may vary.

5. USCS designation is based on visual-manual classification and selected lab testing.

6. The hole location was measured from existing site features and should be considered approximate.

CA FTFW KERN 12(1), 900(1), Trails(1) Kern National Wildlife Refuge

Kern County, California

0 60

Total Depth:

Top Elevation:

Vert. Datum:

Horiz. Datum:

20 40

Geotechnical and Environmental Consultants

102738-001

Hollow-Stem Auger 2R Drilling

CME-75

LEGEND

Drilling Method:

Drilling Company:

Drill Rig Equipment:

Other Comments:

G ro un d

W at er

D ep th , f t.

Standard Penetration Test

Grab Sample

D ep th , f t.

Latitude:

Longitude:

Station:

Offset:

20 40

QCL 3

~ 35.76036° ~ -119.58048°

M A

S T

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Liquid Limit Natural Water Content

% Fines % Water Content

Plastic Limit

(<0.075mm)

(blows/foot)PENETRATION RESISTANCE Hammer Wt. & Drop: 140 lbs / 30 inches

-1

S -2

S -3

S -4

3 inches of asphalt over 6.5 inches of base course.

Medium stiff, gray brown, Lean Clay with Sand and Gravel (CL); moist; fine sand, sub-angular gravel.

[A-7-6]

Stiff, gray brown, Fat Clay with Sand and Gravel (CH); moist; fine sand, sub-angular gravel.

[A-7-6]

Stiff, yellow, Sandy Lean Clay (CL); moist; fine sand.

[A-7-6]

BOTTOM OF BORING

COMPLETED ON 04/19/2019

G ro un dw at er

N ot

E nc ou nt e re d D ur in g D ri lli ng

0.3

0.8

4.0

8.0

10.5

June 2019

Sample Not Recovered

Hole Diam.:

Rod Type.:

Hammer Type:

SHANNON & WILSON, INC.

10.5 ft.

FIG. A-2

S am pl es

NOTES

LOG OF BORING SW-02

8 in.

2"

Automatic

S ym bo l

Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual.

SOIL DESCRIPTION

1. Refer to Figures A-1 and A-2 for explanation of symbols, codes, abbreviations and definitions.

2. The stratification lines represent the approximate boundaries between soil types, and the transition may be gradual.

3. The discussion in the text of this report is necessary for a proper understanding of the nature of the subsurface materials.

4. Groundwater level, if indicated above, is for the date specified and may vary.

5. USCS designation is based on visual-manual classification and selected lab testing.

6. The hole location was measured from existing site features and should be considered approximate.

CA FTFW KERN 12(1), 900(1), Trails(1) Kern National Wildlife Refuge

Kern County, California

0 60

Total Depth:

Top Elevation:

Vert. Datum:

Horiz. Datum:

20 40

Geotechnical and Environmental Consultants

102738-001

Hollow-Stem Auger 2R Drilling

CME-75

LEGEND

Drilling Method:

Drilling Company:

Drill Rig Equipment:

Other Comments:

G ro un d

W at er

D ep th , f t.

Standard Penetration Test

Grab Sample

D ep th , f t.

Latitude:

Longitude:

Station:

Offset:

20 40

QCL 3

~ 35.76073° ~ -119.57991°

M A

S T

E R

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Liquid Limit Natural Water Content

% Fines % Water Content

Plastic Limit

(<0.075mm)

(blows/foot)PENETRATION RESISTANCE Hammer Wt. & Drop: 140 lbs / 30 inches

LL=69

6/6/2019-102738_AB B-i

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Appen dix B: Laborat ory Test Results

Appendix B

Laboratory Test Results

CONTENTS

B.1 Introduction ............................................................................................................................ B-1

B.2 Geotechincal Index Tests ....................................................................................................... B-1

B.2.1 Water Content ............................................................................................................ B-1

B.2.2 Grain Size Analysis ................................................................................................... B-1

B.2.3 Atterberg Limits ........................................................................................................ B-1

B.3 Geotechnical Engineering Property Tests ........................................................................... B-2

B.3.1 Corrosion .................................................................................................................... B-2

B.3.2 R-value Testing .......................................................................................................... B-2

Tables

Table B-1: Summary of Laboratory Test Results by Boring

Figures

Figure B-1: Grain Size Distribution

Figure B-2: Plasticity Chart

Figure B-3: R-value Test Results, B-1, S-2

B-1

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B.1 INTRODUCTION

Laboratory tests were completed on soil samples retrieved from the borings in general accordance with American Association of State Highway and Transportation Officials

(AASHTO) test methods and ASTM International (ASTM). The laboratory testing program was performed to classify the materials into similar geologic groups and provide data that can be used for design of the project. The geotechnical laboratory testing was performed at our laboratory in Denver, Colorado. A summary of the laboratory test results is presented in Table B-1. The following sections describe the laboratory testing procedures.

B.2 GEOTECHINCAL INDEX TESTS

B.2.1 Water Content

Water content was determined for selected samples in general accordance with AASHTO

T265, Laboratory Determination of Moisture Content of Soils. To perform this test, a sample was weighed before and after oven-drying, and the water content was calculated. Water content determinations are shown graphically on the boring logs and are also summarized in Table B-1.

B.2.2 Grain Size Analysis

Selected samples were tested for the percentage of material passing the No. 200 sieve in general accordance with AASHTO T11, Standard Method of Test for Materials Finer than

75-μm (No. 200) Sieve in Mineral Aggregates by Washing. The percent fines (silt- and clay-sized particles passing the No. 200 sieve) are shown graphically on the boring logs in

Appendix A and are also summarized in Table B-1.

B.2.3 Atterberg Limits

Soil plasticity was determined by performing Atterberg limits tests on selected fine-grained samples. The tests were completed in general accordance with AASHTO T89, Standard Test

Method for Determining the Liquid Limit of Soils and AASHTO T90, Standard Test Method for Determining the Plastic Limit and Plasticity Index of Soils. The Atterberg limits include liquid limit (LL), plastic limit (PL), and plasticity index (PI equals LL minus PL) and are generally used to assist in classification of soils, to indicate soil consistency (when compared to natural water content), and to provide correlation to soil properties. The results of the

Atterberg limits tests are plotted on a plasticity chart on Figure B-2, shown graphically on the boring logs in Appendix A, and summarized in Table B-1.

B-2

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B.3 GEOTECHNICAL ENGINEERING PROPERTY TESTS

B.3.1 Corrosion

Corrosion testing of select samples was performed for pH, resistivity, sulfate content, and chloride content. Testing for pH and resistivity were completed in general accordance with

AASHTO T289, Standard Method of Test for Determining pH of Soil for Use in Corrosion

Testing and AASHTO T288, Standard Method of Test for Determining Minimum

Laboratory Soil Resistivity, respectively. Sulfate content testing was completed in general accordance with Colorado Department of Transportation laboratory procedure CP-L 2103, Sulfate Ion Content in Soil. Chloride content testing was completed in general accordance with AASHTO T291, Standard Method of Test for Determining Water-Soluble Chloride Ion

Content in Soil. Test results for sulfate and chloride content are given in units of percent by weight. The test results are summarized in Table B-1.

B.3.2 R-value Testing

Hveem Stabilometer (R-value) tests were completed by LaBelle Marvin of Santa Ana, California to evaluate the stiffness of soils that may be used in the subgrade of the roadway.

Bulk samples collected from boring B-1 was used for the test. The test was completed according with Caltrans, California Test Method (CTM) 301, Method for Determining the

Resistance "R" value of Treated and Untreated Bases, Subbase and Basement Soils by the

Stabilometer. The R-value test result, from boring B-1, is attached and are summarized in

Table B-1.

Pavement Design Report

Gravel Sand Fines pH Resistivity Sulfates Chlorides

Top Bottom (%) (%) (%) (%)…