CA FTBL DUMONT DUNES (1) Dumont Dunes Road Pavement Report.pdf

PAVEMENT REPORT

CA FTBL Dumont Dunes Road

San Bernardino County, California

Yeh Project No.: 220-070

September 1, 2021

Prepared for:

Jacobs Engineering Group, Inc.

4601 DTC Boulevard, Suite 700

Denver, Colorado 80237 Attn: Mr. James Mills, P.E.

Prepared by:

Yeh and Associates, Inc.

56 E. Main Street, Suite 104 Ventura, California 93001

Phone: 805-481-9590

56 E. Main Street, Suite 104 Ventura, CA 93001

(805) 481-9590 www.yeh-eng.com

Colorado California Denver | Colorado Springs | Durango | Glenwood Springs | Grand Junction | Greeley Grover Beach | Ventura

PAVEMENT REPORT

CA FTBL Dumont Dunes Road

San Bernardino County, California

Yeh Project No.: 220-070

September 1, 2021

Prepared by:

Loree Berry, P.E. Jonathan Schmidt, E.I.T Sr. Project Manager Staff Engineer

Reviewed by:

Jonathan D. Blanchard, P.E., G.E.

Principal Geotechnical Engineer http://www.yeh-eng.com/

Pavement Report Project No. 220-070 CA FTBL Dumont Dunes Road September 1, 2021 iii

Table of Contents

1. PURPOSE AND SCOPE OF STUDY

2. PROJECT UNDERSTANDING

3. FIELD EXPLORATION AND TESTING

3.1 DRILLING

3.2 OTHER EXPLORATION AND SAMPLING

3.3 LABORATORY TESTING

3.4 GEOLOGIC SETTING

4. SITE CONDITIONS

4.1.1 TERRAIN AND VEGETATION

4.1.2 CLIMATE

4.1.3 EXISTING PAVEMENT SURFACE CONDITION

4.2 SUBSURFACE CONDITIONS

4.2.1 EXISTING PAVEMENT STRUCTURAL SECTION

4.2.2 SUBGRADE CONDITIONS

5. CONCLUSIONS AND RECOMMENDATIONS

5.1 EARTHWORK FACTORS

5.2 LOW WATER CROSSING – STREAMBED SIEVE ANALYSES

5.3 PAVEMENT DESIGN RECOMMENDATIONS

5.3.1 DESIGN TRAFFIC VOLUME AND SUBGRADE

5.3.2 BINDER AND MIX RECOMMENDATIONS

5.3.3 PAVEMENT MAINTENANCE AND DRAINAGE

5.4 CORROSION CONSIDERATIONS

6. NOTES TO CONSTRUCTION

7. MATERIAL SOURCES

7.1 PAVEMENT AND AGGREGATE

7.2 GENERAL BORROW

8. LIMITATIONS

9. REFERENCES

iv

List of Figures

FIGURE 1: PROJECT LOCATION MAP

FIGURE 2: EXISTING LOW WATER CROSSING

FIGURE 3: GEOLOGIC MAP

List of Tables

TABLE 1: EXISTING THICKNESS OF SURFACE COURSE AGGREGATE ENCOUNTERED – DUMONT DUNES ROAD

TABLE 2: SUMMARY OF ENCOUNTERED CONCRETE CORE THICKNESSES

TABLE 3: SUMMARY OF SUBGRADE TEST RESULTS

TABLE 4: SUMMARY OF STREAMBED SAMPLE SIEVE ANALYSES

TABLE 5: RECOMMENDED STRUCTURAL SECTIONS

List of Plates

Field Exploration Plan

List of Appendices

Page

Appendix A – Boring Logs Drilling Photos ................................................................................................................... A-1 to A-6 Boring Log Record ........................................................................................................................ A-7 Boring Logs 20P-01 to 20P-22 ............................................................................................. A-8 to 29 Appendix B – Results of Laboratory Testing Summary of Laboratory Test Results ................................................................................ B-1 to B-3 Mechanical Sieve Analysis .................................................................................................. B-4 to B-5 Corrosivity Tests Summary ............................................................................................................ B-6 R-Value ................................................................................................................................ B-7 to 16 Appendix C – Pavement Design Calculations AASHTO (1993) Spreadsheet Calculations ............................................................................ C-1 to 6

1. PURPOSE AND SCOPE OF STUDY

Yeh and Associates is providing geotechnical services for the design of roadway improvements to the Dumont Dunes Recreation Area project in San Bernardino County, California. The project will improve access to the Dumont Dunes off-highway vehicle (OHV) area and the Little Dumont Dunes area. The location of the site is shown on Figure 1.

The geotechnical evaluation consisted of a program of project coordination, reviewing data, field exploration, laboratory testing, and engineering analyses as a basis for providing the recommendations in this report. This report provides recommended pavement sections and geotechnical considerations for design of the road improvements being prepared by Jacobs.

2. PROJECT UNDERSTANDING

The layout of the proposed improvements is shown on the plan set provided by Jacobs (2021) and described in the Bureau of Land Management Federal Lands Transportation Program (BLM FLTP) Project Scope. In general, the project will improve access on 3.8 miles of aggregate surfaced road leading to the Dumont Dunes off-highway vehicle (OHV) area and 0.1 miles of aggregate surfaced road accessing the Little Dumont Dunes area. The first 3.3 miles of Dumont Dunes Road will receive new asphalt paving and the remaining 0.5 mile of road east of the low water crossing will receive new surface aggregate. Little Dumont Dunes Road will receive new asphalt paving. The project also includes staging areas, drainage control, safety and signage, and replacing a low water crossing of the Amargosa River.

The layout of the site and project stationing is shown on Plate 1 - Field Exploration Plan as referenced to Jacobs (2021) plans. The proposed improvements to Dumont Dunes Road extend from Station

Figure 1: Project Location Map

(Sta.) 100+12 at Highway 127 to 306+69 near the incident command center. The new typical roadway section between Sta. 101+12 to 262+75 and Sta. 265+07 to 267+00 includes an 11-foot-wide paved travel lane, a 1-foot-wide paved shoulder, and a 4-foot-wide gravel shoulder in each direction. The new typical section between Sta. 267+00 and 306+69 will include one 11-foot-wide aggregate surfaced travel lane and one 5-foot-wide gravel shoulder in each direction.

A new low water crossing of the Armargosa River will be provided between Sta. 262+75 and Sta.

265+07 to replace the existing structure. The existing structure has been undermined by scour and erosion and has deteriorated at several locations, as shown in Figure 2.

The low water crossing will be an improved simple ford with 6-inch drainage holes spaced approximately 20 feet center-to-center along the downstream side. The toe wall will allow groundwater trapped under the concrete surface to drain. The structural section of the low water crossing will be reinforced concrete over compacted surface course aggregate.

Little Dumont Dunes Road is located off Highway 127 approximately 3 miles south of Dumont Dunes Road. The proposed improvements to Little Dumont Dunes Road extend from station 502+12 to 506+50. The new typical section for Little Dumont Dunes Road includes an 11-foot-wide paved travel lane, a 1-foot-wide paved shoulder, and a 4-foot-wide gravel shoulder in each direction.

Figure 2: Existing Low Water Crossing

3. FIELD EXPLORATION AND TESTING

The field exploration consisted of drilling along the road alignments, sampling the berm material along the existing road, concrete coring at the low water crossing, and collecting bulk samples from the river crossing on June 23 and 24, 2020. The boring locations are shown on Plate 1. The logs of the borings are presented in Appendix A. Laboratory test results are presented in Appendix B.

3.1 DRILLING

The drilling subcontractor for this project was 2R Drilling, Inc. of Chino California. 2R used a CME-75 truck-mounted rig equipped for hollow stem auger drilling to advance 22 borings to depths ranging from 5 to 10 feet below the existing road surface. The borings were initially drilled through the existing structural section of the aggregate surface road. The sides of the borehole were then scraped by the Yeh field representative, and the thickness of the surface course aggregate was measured and recorded on the logs. Yeh logged the subsurface conditions encountered during the drilling and secured soil samples for subsequent laboratory testing. The sample intervals, a description of the subsurface conditions encountered, field tests, blow counts (N-Values) recorded during drive sampling, and percent recovery are presented on the logs.

Sampling within the borings was performed by driving either a modified California or standard penetration test (SPT) split spoon sampler at typical 5-foot intervals. The SPT sampler has a 2-inch outside diameter, 1-3/8-inch inside diameter and is equipped for but was used without liners. The modified California sampler has a 3-inch outside diameter, 2-3/8-inch inside diameter and was used with 1-inch-high brass liners. Drive samples were collected using a 140-pound automatic trip hammer in accordance with ASTM D-1586 (the Standard Penetration Test) procedures. Bulk samples of the subgrade soil were collected from the augers at the depth intervals noted on the logs.

The borings within the roadway were backfilled with excess soil cuttings. The surface was completed with tamped gravel removed from the surface prior to drilling.

3.2 OTHER EXPLORATION AND SAMPLING

In addition to the hollow stem auger drilling and sampling, the field exploration included the following:

• Yeh collected 6 bulk samples from the berm material approximately every 2,500 feet along the alignment to evaluate its suitability as select borrow material.

• 2R cored the concrete slab at the low water crossing at 4 locations to measure the existing concrete thickness. Yeh’s field engineer recorded the concrete thickness and visually classified subgrade materials. The concrete core locations were patched with rapid set concrete.

• Yeh collected streambed samples from the thalweg of Amargosa River at the low water crossing approximately 200 feet upstream and 200 feet downstream of the existing crossing.

At each location one sample was collected from the armor layer (between 0 and 1 feet below the ground surface) and one sample was collected below the armor layer (between 1 and 2 feet below the ground surface).

3.3 LABORATORY TESTING

Laboratory testing was performed on selected samples recovered from the field exploration program.

Test for moisture content, unit weight, particle size distribution by mechanical sieve and hydrometer analysis, and pH and resistivity were performed at the Yeh office and laboratory in Ventura, California. Tests for soluble sulfates and chlorides were performed by Cooper Testing Laboratories in Palo Alto, California. Tests for R-value were performed by Sequoia Consulting of Orange, California.

The results of laboratory tests are presented in Appendix B. Testing was performed accordance with American Society for Testing and Materials (ASTM) methods as noted on the lab reports. The lab results were then used to check the field classifications and update the classification shown on the final boring logs when needed.

3.4 GEOLOGIC SETTING

Figure 3 presents the regional geology in the site vicinity as mapped by the United States Geological Survey (USGS 2002). The project site is located within the southern portion of the Basin and Range Geomorphic Province of California. The Basin and Range Province is characterized by north-south trending mountain ranges and intervening alluvial filled valleys formed as series of horsts and grabens resulting from ongoing regional extension. Bedrock geology in the region is complex and ranges from Proterozoic to Quaternary sedimentary, igneous and metamorphic rocks. In the vicinity of the project site, Proterozoic marine sedimentary rocks and tertiary volcanic rocks are exposed in the Sperry Hills north of the project alignment and on the north side of the Amargosa River. Tertiary sedimentary rocks are exposed adjacent to the project alignment in the Dumont Hills south of the Amargosa River.

The surface geology along the project alignment is mapped in Figure 2 as entirely within Quaternary Surficial Deposits consisting primarily of unconsolidated sands and gravels. The subsurface conditions encountered along the project alignment consisted of young alluvium (Qay) for the western approximately 2.9 miles along Dumont Dunes Road. The alignment traverses channel deposits within the course of the Amargosa River and old alluvium (Qao) on the south side of the Amargosa River.

4. SITE CONDITIONS

4.1.1 TERRAIN AND VEGETATION

The beginning portion of Dumont Dunes Road (Sta 100+12 to 267+00) travels through generally flat desert terrain bordering the north edge of the Amargosa River valley. The road then crosses the Amargosa river at Sta 265+75 and gradually climbs to the fee collection area near Station 275+00. The road steepens to a maximum gradient of 10-percent after the fee collection area (approximate Sta 285+00) before terminating in the Dumont Dunes OHV area. Little Dumont Dunes Road traverses a short distance of flat desert terrain between Highway127 and the Little Dumont Dunes camping and staging area. Vegetation for both sites consists primarily of sparse creosote scrub and annual grasses but will also include wildflowers during the spring.

4.1.2 CLIMATE

The site is within the high desert region of California. The climate data (www.usclimatedata.com) for Shoshone, California, located approximately 20 miles north of the beginning of Dumont Dunes Road, reports an average annual rainfall of 4.83 inches. Most of the rainfall is reported to occur during the

Figure 3: Geologic Map http://www.usclimatedata.com/ winter months between December and March. The reported monthly average high temperature ranges from a low of 60 degrees for December and January to a high of 107 degrees in July.

4.1.3 EXISTING PAVEMENT SURFACE CONDITION

Dumont Dunes Road. Dumont Dunes Road is a two-lane aggregate surfaced road extending approximately 3.8 miles from Highway 127 into the Dumont Dunes OHV area. The typical width of the roadway varies between 28 and 31 feet. The existing road is generally well maintained with occasional areas of wash boarding, loose aggregate, and rutting. The width of the roadway is bordered by a two-to three-foot high soil berm consisting of a mixture of sand, gravel, broken asphalt concrete, and aggregate. A low water crossing is located where Dumont Dunes Road crosses the Amargosa River. The low water crossing is composed of concrete, approximately 175 feet long and generally aligned in the north-south direction. The concrete on the eastern half of the structure is in good condition and has isolated areas of low severity longitudinal cracking. The concrete on the western half of the structure is in poor condition and has frequent areas of scaling and polished aggregate.

Little Dumont Dunes Road. Little Dumont Dunes Road is a 0.1-mile, two-lane aggregate-surfaced road providing access to the Dumont Dunes Little Dunes OHV area. The existing road is in poor condition with frequent areas of wash boarding, loose aggregate, and rutting. The surface aggregate ends approximately 350 feet east of Highway 127 by the Little Dumont Dunes OHV area informational kiosk.

4.2 SUBSURFACE CONDITIONS

The approximate boring locations are shown on Plate 1. Logs of the borings are included in Appendix A.

4.2.1 EXISTING PAVEMENT STRUCTURAL SECTION

The pavement structural section encountered in the drill holes (20P-01 through 20P-22) consisted of approximately 9 to 14 inches of surface course aggregate outside the limits of the low water crossing on Dumont Dunes Road and 3 inches of poorly graded fine gravel on Little Dumont Dunes Road. A description of the conditions encountered is summarized in Table 1 below.

Table 1: Existing Thickness of Surface Course Aggregate Encountered – Dumont Dunes Road

Boring No. Station1

Pavement (inches)

Aggregate Thickness (inches) Subgrade Soil

20P-01 100+00 -- 11 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-02 113+00 -- 11 SILTY SAND with GRAVEL (SM)

Boring No. Station1

Pavement (inches)

Aggregate Thickness (inches) Subgrade Soil

20P-03 124+00 -- 11 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-04 135+00 -- 11 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-05 145+00 -- 10 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-06 157+00 -- 12 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-07 168+00 -- 12 SILTY SAND (SM)

20P-08 178+00 -- 12 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-09 188+00 -- 11 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-10 202+00 -- 10 Poorly graded GRAVEL with SILT and SAND (GP-GM)

20P-11 214+00 -- 9 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-12 220+00 -- 14 Poorly graded GRAVEL with SILT and SAND (GP-GM)

20P-13 241+00 -- 12 SILTY GRAVEL with SAND (GM)

20P-14 257+00 -- 11.5 Poorly graded GRAVEL with SILT and SAND (GP-GM)

20P-15 262+00 -- 12 Poorly graded GRAVEL with SILT and SAND (GP-GM)

20P-16 266+00 12 (Concrete) 62 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-17 272+00 -- 12 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-18 280+00 -- 12 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-19 290+00 -- 11 Poorly graded SAND with SILT (SP-SM)

20P-20 295+00 -- 12 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-21 305+00 -- 13 Poorly graded SAND with SILT and GRAVEL (SP-SM)

20P-22 505+50 -- 33 (fine gravel) Poorly graded SAND with SILT (SP-SM)

Notes:

1. Stationing is approximate.

2. Concrete from low water crossing is underneath aggregate base in boring 20P-16.

3. Boring 20P-22 was drilled at the end of Little Dumont Dunes Road, outside of the extents of existing the aggregate surface course. No borings were drilled in the aggregate surfaced portion of the road between Highway 127 and the informational kiosk.

4. No borings were drilled in Highway 127

Dumont Dunes Low Water Crossing. An existing low water crossing is located where Dumont Dunes Road crosses the Amargosa River. The existing concrete was cored at four locations along the low water crossing to measure the existing concrete thickness and visually classify the subgrade material, summarized in Table 2. The concrete was underlain by alluvial sand and gravel.

Table 2: Summary of Encountered Concrete Core Thicknesses

4.2.2 SUBGRADE CONDITIONS

The subgrade soil encountered in the borings was generally comprised of sands and gravels, consistent with the mapped surface geology discussed in section 3.4.

Dumont Dunes Road. Subgrade material encountered below the existing surface course aggregate typically consisted of medium dense to very dense poorly graded sand with silt and gravel, and poorly graded gravel with silt and sand. R-value test results for samples of the subgrade material ranged from 73 to 75, characteristic of “very good” subgrade conditions for aggregate surface roads (FHWA 2010). An R-value test result of 69 was obtained for a composite sample of the berm material, that also corresponds to “very good” subgrade conditions.

Little Dumont Dunes Road. Subgrade material encountered below the existing surface course aggregate was typically poorly graded sand with silt. An R-value result of 63 was obtained for a sample of the subgrade soil. A summary of the laboratory test results for the various geologic units is presented in Table 3 below:

Table 3: Summary of Subgrade Test Results1

Geologic Unit Location

Dry Unit Wt.

(pcf)

Moisture Content

Particle Size

Analyses (%G, %S, %F) R-Value Corrosivity

Alluvial Deposits (Qay, Qc, and Qoa)

Dumont Dunes Road (20P-01 through 20P-21) 108 - 122 1-6

19 - 49 G 39 - 74 S 5 - 15 F

73- 75 pH = 8.39 - 9.65 ρ = 443 to 2526 Ω-cm

SO42= 120 - 641 mg/kg, Cl- = 77 - 202 mg/kg

1 Geotechnical properties are noted for dry unit weight (ɣd) and moisture content (wo); particle size as percent gravel (G), sand size (S) and fines content (F); R-Value; pH and electrical resistivity (ρ) in ohm-centimeters (Ω-cm), soluble sulfates (SO42-) and chlorides (CL-) in mg/kg.

Core ID Location Relative Surface

Condition of Concrete Existing Concrete Thickness

1 Northern portion of eastern slab Less weathered 5 inches

2 Southern portion of eastern slab Less weathered 5 inches

3 Northern portion of western slab More weathered 7 inches

4 Southern portion of western slab More weathered 12 inches

Geologic Unit Location

Dry Unit Wt.

(pcf)

Moisture Content

Particle Size

Analyses (%G, %S, %F) R-Value Corrosivity

Artificial Fill (af) Berm Samples -- -- 27 - 36 G 60 - 65 S

4 - 8 F 69 --

Channel Alluvium (Qc)

Streambed Samples -- --

33 - 54 G 43 - 60 S

3 - 5 F

Eolian Deposits (Qe)

Little Dumont Dunes Road

(20P-22) 117 1

2 G 93 S 6 F pH = 9.10 ρ = 997 Ω-cm

SO42= 229 - 469 mg/kg, Cl- = 95 - 230 mg/kg

5. CONCLUSIONS AND RECOMMENDATIONS

5.1 EARTHWORK FACTORS

The subgrade generally consisted of medium dense to very dense sand and gravel. The drive samples tested had dry unit weights ranging from approximately 108 to 122 pounds per cubic foot, with an average of 114 pounds per cubic foot. Drive sample disturbance can occur from compaction of samples during driving, loosening of the soil when recovering the sampler from the drill hole, and during trimming in the laboratory.

Differences in soil density may occur in areas where the existing pavement subgrade and or other fill materials were compacted, softer soil is present near the subgrade elevation, and variations in soil type. The estimated earthwork factors2 do not account for losses for removal of vegetation or unsuitable material. An average earthwork factor of 1 can be used considering reconditioning the existing structural section. An average earthwork factor of 1.1 can be used for areas where the subgrade will be compacted outside the limits of the existing structural section, or in areas where removal and recompaction are recommended. The earthwork factors are approximate and should be checked and adjusted as the grading work progresses.

5.2 LOW WATER CROSSING – STREAMBED SIEVE ANALYSES

Yeh collected bulk samples from the thalweg of the Amargosa River upstream and downstream of the existing low water crossing. At each location one sample was collected from the armor layer (0 to 1

2 The earthwork factor represents the ratio of the existing in-situ unit weight of the soil before construction to the unit weight of the same soil after compaction. For example, an earthwork factor of 0.95 represents a 5 percent loss in the volume of soil following compaction. An earthwork factor of 1.05 represents a 5 percent gain in volume of the soil or pavement following compaction due to bulking of a relatively dense material.

foot below the ground surface) and one collected from below the armor layer (1 to 2 feet below the ground surface). Samples were split down to select a sample size suitable for mechanical sieve analysis. No particles larger than 3-inches were noted in the field within the thalweg. Table 4 summarizes the sieve results and estimated D50 values for each sample. Grain size distribution curves from the mechanical sieve analysis for each sample are included in Appendix B.

Table 4: Summary of Streambed Sample Sieve Analyses

Sample Location

Depth (feet below ground surface) USCS

Gravel % Sand

% Fines (<#200)

D50 (mm)

Upstream 0 – 1 Well-graded SAND with GRAVEL (SW) 35 60 5 2.8

Upstream 1 – 2 Well-graded GRAVEL with SILT and SAND

(GW-GM) 50 45 5 4.8

Downstream 0 – 1 Poorly graded SAND with GRAVEL (SP) 43 54 3 3.3

Downstream 1 – 2 Well-graded GRAVEL with SAND (GW) 54 43 3 5.7

5.3 PAVEMENT DESIGN RECOMMENDATIONS

The recommended structural sections for design of the Dumont Dunes Road and Little Dumont Dunes Road improvements were estimated using methods from Chapter 11 of the FHWA Federal Lands Highway Project Development and Design Manual (FHWA 2008), the Aggregate Surfacing Design Standards and Guidance CFLHD Supplement 11.4.2-1 (CFLHD 2010), and the AASHTO Guide for the Design of Pavement Structures (AASHTO 1993). Preliminary pavement structural sections were evaluated and presented in the Yeh Preliminary Pavement Recommendations memorandum (Yeh 2020b). The pavement concepts were selected during preliminary design and discussions with the project team and include: hot mix asphalt (HMA) over full depth reclamation of spread berm material and at least the upper 2 inches of the existing base course; imported aggregate base course (ABC) for the aggregate surfaced segment of Dumont Dunes Road, and HMA over compacted subgrade for Little Dumont Dunes Road. The spreadsheet calculations for our recommended traffic loading and thickness recommendations are presented in Appendix C.

5.3.1 DESIGN TRAFFIC VOLUME AND SUBGRADE

Traffic Data. The traffic loading for Dumont Dunes Road and Little Dumont Dunes Road was developed based upon information cited in a report titled Recreation Fee Program Management Evaluation California State Fee Projects, dated July 2008 and subsequent discussions with Jacobs, BLM, and FHWA-CFLHD. The recommended structural sections assume an average daily traffic of 400 vehicles per day for Dumont Dunes Road and 100 vehicles per day for Little Dumont Dunes consisting of 20 percent Class 2 vehicles, 55 percent Class 5 vehicles, and 25 percent Class 6 vehicles. The design equivalent single axle loads (ESALs) are 1,119,139 for Dumont Dunes Road and 279,785 for Little

Dumont Dunes Road. The estimated ESALs are for a 3R project having a design life of 20 years and 2 percent growth.

Subgrade. The subgrade encountered along Dumont Dunes Road and Little Dumont Dunes Road is described in Section 4.2.2. The recommended structural section thicknesses for Dumont Dunes Road were estimated considering an R-value of 70 corresponding to a resilient modulus of 25,317 psi. The minimum thickness of surface course aggregate for the east end of Dumont Dunes Road was estimated considering “very good” subgrade conditions, “high” traffic levels, and climate region “IV”.

The recommended structural section thicknesses for Little Dumont Dunes Road were estimated considering an R-value of 60 corresponding to a resilient modulus of 18,259 psi.

Table 5 summarizes the recommended structural sections and construction approaches for the three project road segments.

Table 5: Recommended Structural Sections

Location (station) Pavement Concept Approach Structural

Section

Dumont Dunes Road (Sta. 100+12 to 262+75 and Sta.

265+07 to 267+00)

HMA over full depth reclamation of berm material** and existing base course

- Distribute berm material over the roadway as select borrow, removing rocks greater than 3 inches

- Perform full depth reclamation on all layers of existing asphalt, gravel berm, and existing road base to a depth of 2” below existing road surface or 8” total, whichever is less

- Moisture condition and compact to 95% relative compaction to provide a minimum 6” thickness of compacted material

- Place new HMA surface course

3” HMA

over

8” full depth reclamation

Little Dumont Dunes Road

(Sta. 502+12 to 506+50)

HMA over compacted subgrade

- Pulverize existing aggregate surface road to depth of 6 inches, moisture condition, and compact in-place to 95% relative compaction

- Place new HMA

3” HMA

over

6” compacted subgrade

Aggregate surfaced segment of Dumont

Dunes Road

(Sta. 267+00 to 306+69)

Aggregate surface course

- Scarify, moisture condition, and compact existing road surface to depth of 6” and compact in-place to 95% relative compaction

- Place 4” thickness of imported ABC material

4” of imported aggregate base course (ABC)

** The mixture of berm material and pulverized existing aggregate base are expected to meet the requirements for select borrow based upon R-value and gradation testing. The berm material should be cleansed of organics, deleterious, and oversized material prior to placement.

5.3.2 BINDER AND MIX RECOMMENDATIONS

The State of California (Caltrans 2012) has adopted a program of Asphalt Binder Grade Selection that classifies this project area as a Desert Region. The recommended binder for dense graded HMA for this project is PG 70-10.

This project is in a relatively remote location and we understand the location of existing commercial asphalt plants may result in relatively long-haul distance to the construction site. Loss of temperature and segregation of the hot asphalt mix can occur during transport. We recommend that the project specifications require the use of a material transfer vehicle at the point of placement to provide more uniform temperatures and prevent segregation of the mix during placement.

5.3.3 PAVEMENT MAINTENANCE AND DRAINAGE

The pavement condition should be periodically evaluated to help plan and scope the need for maintenance and rehabilitation following the initial construction of the pavement. Maintenance of asphalt concrete pavements should typically include periodic fog, chip or slurry seals to reduce the potential for weathering and overlaying with additional HMA when needed to strengthen and further the life of the pavement. Pavement condition index and deflection surveys can be performed to evaluate the structural capacity of pavements and the need for future overlays and maintenance.

Surface drainage should be improved to reduce the potential for water to pond on the pavement or shoulder, and to prevent concentrated flows of surface water from running over slopes.

5.4 CORROSION CONSIDERATIONS

FHWA foundation design manuals generally consider the following as indicative of a potentially corrosive soil or site condition:

• pH less than 5.5.

• Resistivity less than 2000-ohm-cm.

• Sulfate concentration greater than 1,000 ppm.

Corrosion test data is presented in Table 3 and Appendix B. In general, test results indicate a potentially corrosive requirement. Corrosion test data should be considered in design of reinforced concrete or steel structures.

6. NOTES TO CONSTRUCTION

The existing base course material and gravel berm material along Dumont Dunes are “very good” quality material. The intent is to spread the existing berm material across the roadway and incorporate both the berm material and the upper 2 inches minimum of existing base course material to provide 8” of FDR material for support of the new pavement.

7. MATERIAL SOURCES

7.1 PAVEMENT AND AGGREGATE

The main material requirements for this project will likely include hot mix asphalt and aggregates available from commercial suppliers in nearby cities such as Pahrump, Las Vegas, or Baker. Haul times to the site could be on the order of one to two hours. We have not contacted suppliers about their ability to supply aggregates or materials in the quantities needed for this project. This report is not a statement that these potential suppliers are pre-approved nor implies that the plants will meet quality control and material compliance for the project or materials to be placed at the site.

7.2 GENERAL BORROW

Excavated onsite soil and excess berm material should be suitable for reuse as general borrow.

Excavated onsite soil and rock may contain large particles that will need to be broken down or segregated from the fill to make the material suitable for compaction. Control of moisture content, compaction layer thickness and selecting suitable equipment will be necessary to achieve the relative compaction for compacted fill.

8. LIMITATIONS

This study has been conducted in general accordance with currently accepted geotechnical practices in this area for use by the client for design purposes. The conclusions and recommendations submitted in this report are based upon the data obtained from field reconnaissance, drilling and sampling, and our understanding of the proposed project and type of construction described in this report. If there are any changes in the project or site conditions, Yeh should review those changes and provide additional recommendations, if needed. Any modifications to the recommendations of this report or approval of changes made to the project should not be considered valid unless they are made in writing. The report and drawings contained in this report are intended for design-input; and are not intended to act as construction drawings or specifications.

Site conditions will vary between points of observation or sampling, seasonally, and with time. The nature and extent of subsurface variations across the site may not become evident until excavation is performed. If during construction, fill, soil, or water conditions appear to be different from those described herein, Yeh should be advised and provided the opportunity to evaluate those conditions and provide additional recommendations, if necessary. The geotechnical professional should observe portions of the construction and site conditions, such as excavations, exposed subgrades and earthwork, to evaluate whether the conditions encountered are consistent with those assumed for design, and to provide additional recommendations during construction, if needed.

9. REFERENCES

American Association of State Highway and Transportation Officials. (AASHTO 1993). AASHTO Guide for Design of Pavement Structures.

Bureau of Land Management. (BLM 2008). Recreation Fee Program Management Evaluation California State Fee Projects. Issued July 2008.

Bureau of Land Management Federal Lands Transportation Program. (BLM 2018). Project Scope – Dumont Dunes Road, Central District, California.

Jacobs Engineering Group. (2021). Plans Titled: CA FTBL Dumont Dunes (1), Dumont Dunes Road, Off- Highway Vehicle (OHV) Recreation Area, San Bernadino County, 95% Submittal, dated June 10, 2021.

U.S. Department of Transportation, Federal Highway Administration. (FHWA 2008). Federal Lands Highway Project Development and Design Manual, Chapter 11 – Pavements. Issued March 2008.

U.S. Department of Transportation, Federal Highway Administration. (FHWA 2010). Aggregate Surfacing Design Standards and Guidance. CFLHD Supplement 11.4.2-1. Issued November 2010.

U.S. Department of Transportation, Federal Highway Administration. Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects FP-14, U.S.

Yeh and Associates, Inc. (2020a), Summary of Geotechnical Exploration, CA FTBL DUMONT DUNES ROAD, San Bernardino County, California, memorandum prepared for Jacobs Engineering Group, dated August 28, 2020.

Yeh and Associates, Inc. (2020b), Preliminary Pavement Structural Sections, CA FTBL Dumont Dunes Road, San Bernardino County, California, memorandum prepared for Jacobs Engineering Group, dated December 7, 2020.

220+00

200+00 280+00

0+

140+00

120+00+00

160+00

180+00

240+00

260+00

PLATEPROJECT NAME:

PROJECT NUMBER: REVISED DATE:

BLM Federal Lands Transporta�on Program

Dumont Dunes Road Central Desert District, CA

220-070 6/29/2021

Field Exploration Plan 20000 feet

North

Legend:

Hollow Stem Auger Boring (depth)

Hollow Stem Auger Boring (depth)

Dumont Dunes Road

Highw ay 127

Li�le Dumont Dunes Road

Dumont Dunes Road

Exis�ng Helipad

Low Water Crossing

Amargosa River

(5-�)

(10-�) feet

North

APPENDIX A - BORING LOGS

Pavement Report Yeh Project No. 220-070 CA FTBL Dumont Dunes Road June 30, 2021

20P-01 (looking east) 20P-02 (looking east)

20P-03 (looking east) 20P-04 (looking west)

Page A-1 of 29

20P-05 (looking east) 20P-06 (looking east)

20P-07 (looking west) 20P-08 (no picture)

Page A-2 of 29

20P-09 (looking east) 20P-10 (looking east)

20P-11 (looking east) 20P-12 (looking west)

Page A-3 of 29

20P-13 (looking east) 20P-14 (looking east)

20P-15 (looking south) 20P-16 (looking south)

Page A-4 of 29

20P-16 (looking south) 20P-17 (looking south)

20P-18 (looking west) 20P-19 (looking west)

Page A-5 of 29

20P-20 (looking north) 20P-21 (looking south)

20P-22 (looking east)

Page A-6 of 29

DATE

6/30/2021

PROJECT NAME

CA FTBL Dumont Dunes Road

Shrinkage Limit (ASTM D427)

Swell Potential (ASTM D4546)

Unconfined Compression - Soil (ASTM D2166) Unconfined Compression - Rock (ASTM D7012)

Unconsolidated Undrained Triaxial

(ASTM D2850)

Vane Shear (AASHTO T 223-96 [2004])

-200

VS

UW

UU

UC

Permeability (ASTM 5084)

Unit Weight (ASTM D4767, ASTM D7263)

200 Wash (ASTM D1140)

SILTY, CLAYEY SAND

Group Names

SC-SM

Graphic / Symbol Graphic / Symbol Group Names

Standard California Sampler (2.5" O.D.)

C

CL

CP

CR

CU

Corrosion, Sulfates, Chlorides (CTM 643; ASTM

D4972, ASTM G187, ASTM D4327)

Compaction Curve (ASTM D1557)

Direct Shear (ASTM D3080)

Expansion Index (ASTM D4829)

PP

PM

PL

PI

PA

P

OC

M

GRAVELLY ORGANIC SILT

GRAVELLY ORGANIC SILT with SAND

ORGANIC SILT

Well-graded SAND with CLAY and GRAVEL (or SILTY CLAY and GRAVEL)

SILTY, CLAYEY SAND with GRAVEL

CLAYEY SAND with GRAVEL

SILTY SAND with GRAVEL

GROUP SYMBOLS AND NAMES

DRILLING METHOD SYMBOLS

OL

EI

GC

GP

GC-GM

SANDY ORGANIC SILT

Lean CLAY with SAND Lean CLAY with GRAVEL

SANDY lean CLAY with GRAVEL

ORGANIC lean CLAY

GRAVELLY ORGANIC lean CLAY GRAVELLY ORGANIC lean CLAY with SAND

Fat CLAY

Elastic SILT with GRAVEL SANDY elastic SILT

SANDY elastic SILT with GRAVEL GRAVELLY elastic SILT GRAVELLY elastic SILT with SAND

ORGANIC elastic SILT

SANDY ORGANIC SILT with GRAVEL

CH

MH

OH

OL/OH

Rock Core Grab Sample

TV

SW

SL

SG

SE

R

Poorly graded SAND with SILT and GRAVEL

SANDY lean CLAY

GRAVELLY lean CLAY

ORGANIC lean CLAY with SAND ORGANIC lean CLAY with GRAVEL SANDY ORGANIC lean CLAY

SANDY ORGANIC lean CLAY with GRAVEL

Fat CLAY with SAND Fat CLAY with GRAVEL SANDY fat CLAY

SANDY fat CLAY with GRAVEL GRAVELLY fat CLAY GRAVELLY fat CLAY with SAND

ORGANIC fat CLAY ORGANIC fat CLAY with SAND ORGANIC fat CLAY with GRAVEL SANDY ORGANIC fat CLAY

Elastic SILT with SAND

Well-graded GRAVEL

Poorly graded GRAVEL with SILT

GRAVELLY lean CLAY with SAND

DS

SP-SC

SW

SP

Piston Sampler

SW-SM

SILTY, CLAYEY GRAVEL with SAND

CLAYEY GRAVEL with SAND

SILTY GRAVEL with SAND

Modified California Sampler (3" O.D.)

GRAVELLY SILT with SAND

SILT

ORGANIC SILT with SAND ORGANIC SILT with GRAVEL

Liquid Limit, Plastic Limit, Plasticity Index

(ASTM D4318)

Consolidation (ASTM D2435)

Collapse Potential (ASTM D5333)

Consolidated Undrained Triaxial (ASTM D4767)

Moisture Content (ASTM D2216)

Organic Content (ASTM D2974)

Particle Size Analysis (ASTM D422-63 [2007])

Point Load Index (ASTM D5731)

Standard Penetration Test (SPT) (2" O.D.)

OL

SC

GW

GW-GM

CL

CL-ML

ML

COBBLES and BOULDERS

BOULDERS

PT

SILTY GRAVEL

CLAYEY GRAVEL

SILTY, CLAYEY GRAVEL

SILTY SAND

CLAYEY SAND

SILTY CLAY

SILTY CLAY with SAND SILTY CLAY with GRAVEL

SANDY SILTY CLAY

SANDY SILTY CLAY with GRAVEL

GRAVELLY SILTY CLAY

GRAVELLY SILTY CLAY with SAND

SILT with SAND SILT with GRAVEL

SANDY SILT

SANDY SILT with GRAVEL

SANDY ORGANIC fat CLAY with GRAVEL GRAVELLY ORGANIC fat CLAY GRAVELLY ORGANIC fat CLAY with SAND

Elastic SILT

ORGANIC elastic SILT with GRAVEL SANDY elastic ELASTIC SILT

COBBLES

Well-graded GRAVEL with SAND

Well-graded GRAVEL with SILT

Well-graded GRAVEL with CLAY and SAND (or SILTY CLAY and SAND)

Well-graded SAND with CLAY (or SILTY CLAY)

Poorly graded GRAVEL

Poorly graded GRAVEL with CLAY (or SILTY CLAY)

Poorly graded SAND with SILT

Poorly graded SAND with CLAY (or SILTY CLAY)

Poorly graded SAND with CLAY and GRAVEL (or SILTY CLAY and GRAVEL)

Lean CLAY

ORGANIC elastic SILT with SAND

SANDY ORGANIC elastic SILT with GRAVEL GRAVELLY ORGANIC elastic SILT GRAVELLY ORGANIC elastic SILT with SAND

GW-GC

GP-GM

GP-GC

GM

Well-graded SAND with SILT

SW-SC

SP-SM

GRAVELLY SILT

ORGANIC SOIL

ORGANIC SOIL with SAND ORGANIC SOIL with GRAVEL

SANDY ORGANIC SOIL

SANDY ORGANIC SOIL with GRAVEL

GRAVELLY ORGANIC SOIL

GRAVELLY ORGANIC SOIL with SAND

OH

SM

Auger Drilling

FIELD AND LABORATORY TESTS

WATER LEVEL SYMBOLS

Dynamic Cone or Hand Driven Diamond CoreRotary Drilling

Static Water Level Reading (long-term)

Shelby Tube

Bulk Sample Other (see remarks)

Static Water Level Reading (short-term)

First Water Level Reading (during drilling)

SHEET

SAMPLER GRAPHIC SYMBOLS

PEAT

Well-graded GRAVEL with SILT and SAND

Well-graded GRAVEL with CLAY (or SILTY CLAY)

Well-graded SAND

Well-graded SAND with GRAVEL

Well-graded SAND with SILT and GRAVEL

Poorly graded GRAVEL with SAND

Poorly graded GRAVEL with SILT and SAND

Poorly graded GRAVEL with CLAY and SAND (or SILTY CLAY and SAND)

Poorly graded SAND

Poorly graded SAND with GRAVEL

Pressure Meter

Pocket Penetrometer

Pocket Torvane

R-Value (CTM 301)

Sand Equivalent (CTM 217)

Specific Gravity (AASHTO T 100)

REPORT TITLE

LEGEND FOR SOIL CLASSIFICATION

Page A-7 of 29

50/5"

R (R-Value = 73)

-200 (20% G, 74% S, 6% F)

11'' AGGREGATE BASE.

Poorly graded SAND with SILT and GRAVEL (SP-SM), very dense, reddish brown, dry, fine to coarse GRAVEL, fine and coarse SAND, (ALLUVIUM).

Bottom of borehole at 5.5 ft bgs

This Boring Record was developed in accordance with the CFL-FHWA Geotechnical Technical Guidance Manual (2007) except as noted on the Soil or Rock Legend or below.

A

TOTAL DEPTH OF BORING

5.5 ft

GROUNDWATER

READINGS

FINAL BY

L. Berry

DRILL RIG

CME 75

WEATHER NOTES

Sunny, warm, light breeze

BORING NUMBER

20P-01

SURFACE ELEVATION

LOGGED BY

J. Schmidt

DRILLER

2R Drilling, Inc.

BEGIN DATE

6-30-20

COMPLETION DATE

6-30-20

DRILLING METHOD

8" Hollow-Stem Auger

HAMMER TYPE

140-lb Automatic Trip BOREHOLE LOCATION (Lat/Long or North/East and Datum)

DURING DRILLING

Not encountered

AFTER DRILLING (DATE)

BACKFILLED WITH

Backfilled with cuttings

LOCATION DESCRIPTION

Dumont Dunes Rd, Right of CL

BOREHOLE LOCATION (Offset, Station, Line)

Sta. 100+00 M at er ia l

G ra ph ic s

PROJECT NUMBER

220-070

SHEET

M oi st ur e C on te nt

D E

P T

H ft)

BORING NUMBER

20P-01

D ry

U ni t W ei gh t

(p cf

B lo w s pe r in

R ec ov er y

E

LE

V A

T

IO

N ft)

REVISION DATE

6/30/2021

D ril lin g

M et ho d

C as in g

D ep th

Remarks

S he ar S tr en gt h

(k sf

DESCRIPTION

S am pl e

Lo ca tio n

S am pl e

N um be r

B lo w s pe r fo ot

R Q

D

F F

(F ra ct ur es /F oo t)

PROJECT NAME

CA FTBL Dumont Dunes Road

B

R

S T

A N

D A

R D

-0

LO

G S

A N

D L

A B

.G P

J C

A

LI

F O

R N

IA

Y

E H

L

IB

R A

R Y

Y

E H

V

A P

R

IL

0)

C F

L.

G

LB

/3 0/

Page A-8 of 29

100 -200 (19% G, 69% S, 12% F)

11'' AGGREGATE BASE.

SILTY SAND with GRAVEL (SM), very dense, grayish brown, dry, fine to coarse GRAVEL, fine and coarse SAND, (ALLUVIUM).

Dense.

Bottom of borehole at 5.5 ft bgs

This Boring Record was developed in accordance with the CFL-FHWA Geotechnical Technical Guidance Manual (2007) except as noted on the Soil or Rock Legend or below.

TOTAL DEPTH OF BORING

5.5 ft

GROUNDWATER

READINGS

FINAL BY

L. Berry

DRILL RIG

CME 75

WEATHER NOTES

Sunny, warm, light breeze

BORING NUMBER

20P-02

SURFACE ELEVATION

LOGGED BY

J. Schmidt

DRILLER

2R Drilling, Inc.

BEGIN DATE

6-30-20

COMPLETION DATE

6-30-20

DRILLING METHOD

8" Hollow-Stem Auger

HAMMER TYPE

140-lb Automatic Trip BOREHOLE LOCATION (Lat/Long or North/East and Datum)

DURING DRILLING

Not encountered

AFTER DRILLING (DATE)

BACKFILLED WITH

Backfilled with cuttings

LOCATION DESCRIPTION

Dumont Dunes Rd, Left of CL

BOREHOLE LOCATION (Offset, Station, Line)

Sta. 113+00 M at er ia l

G ra ph ic s

PROJECT NUMBER

220-070

SHEET

M oi st ur e C on te nt

D E

P T

H ft)

BORING NUMBER

20P-02

D ry

U ni t W ei gh t

(p cf

B lo w s pe r in

R ec ov er y

E

LE

V A

T

IO

N ft)

REVISION DATE

6/30/2021

D ril lin g

M et ho d

C as in g

D ep th

Remarks

S he ar S tr en gt h

(k sf

DESCRIPTION

S am pl e

Lo ca tio n

S am pl e

N um be r

B lo w s pe r fo ot

R Q

D

F F

(F ra ct ur es /F oo t)

PROJECT NAME

CA FTBL Dumont Dunes Road

B

R

S T

A N

D A

R D

-0

LO

G S

A N

D L

A B

.G P

J C

A

LI

F O

R N

IA

Y

E H

L

IB

R A

R Y

Y

E H

V

A P

R

IL

0)

C F

L.

G

LB

/3 0/

Page A-9 of 29

-200 (34% G, 61% S, 5% F)

11'' AGGREGATE BASE.

Poorly graded SAND with SILT and GRAVEL (SP-SM), very dense, light red, dry, fine to coarse GRAVEL, fine and coarse SAND, (ALLUVIUM).

Dense.

Bottom of borehole at 5.5 ft bgs

This Boring Record was developed in accordance with the CFL-FHWA Geotechnical Technical Guidance Manual (2007) except as noted on the Soil or Rock Legend or below.

TOTAL DEPTH OF BORING

5.5 ft

GROUNDWATER

READINGS

FINAL BY

L. Berry

DRILL RIG

CME 75

WEATHER NOTES

Sunny, warm, light breeze

BORING NUMBER

20P-03

SURFACE ELEVATION

LOGGED BY

J. Schmidt

DRILLER

2R Drilling, Inc.

BEGIN DATE

6-30-20

COMPLETION DATE

6-30-20

DRILLING METHOD

8" Hollow-Stem Auger

HAMMER TYPE

140-lb Automatic Trip BOREHOLE LOCATION (Lat/Long or North/East and Datum)

DURING DRILLING

Not encountered

AFTER DRILLING (DATE)

BACKFILLED WITH

Backfilled with cuttings

LOCATION DESCRIPTION

Dumont Dunes Rd, Right of CL

BOREHOLE LOCATION (Offset, Station, Line)

Sta. 124+00 M at er ia l

G ra ph ic s

PROJECT NUMBER

220-070

SHEET

M oi st ur e C on te nt

D E

P T

H ft)

BORING NUMBER

20P-03

D ry

U ni t W ei gh t

(p cf

B lo w s pe r in

R ec ov er y

E

LE

V A

T

IO

N ft)

REVISION DATE

6/30/2021

D ril lin g

M et ho d

C as in g

D ep th

Remarks

S he ar S tr en gt h

(k sf

DESCRIPTION

S am pl e

Lo ca tio n

S am pl e

N um be r

B lo w s pe r fo ot

R Q

D

F F

(F ra ct ur es /F oo t)

PROJECT NAME

CA FTBL Dumont Dunes Road

B

R

S T

A N

D A

R D

-0

LO

G S

A N

D L

A B

.G P

J C

A

LI

F O

R N

IA

Y

E H

L

IB

R A

R Y

Y

E H

V

A P

R

IL

0)

C F

L.

G

LB

/3 0/

Page A-10 of 29

2 10921

CR (pH = 8.45, r = 2,526 ohm-cm, SO4

2- = 120 mg/kg, Cl- = 77 mg/kg)

-200 (28% G, 65% S, 7% F)

11'' AGGREGATE BASE.

Poorly graded SAND with SILT and GRAVEL (SP-SM), very dense, light reddish brown, dry, fine to coarse GRAVEL, fine to coarse SAND, (ALLUVIUM).

Medium dense.

Bottom of borehole at 5.5 ft bgs

This Boring Record was developed in accordance with the CFL-FHWA Geotechnical Technical Guidance Manual (2007) except as noted on the Soil or Rock Legend or below.

B

TOTAL DEPTH OF BORING

5.5 ft

GROUNDWATER

READINGS

FINAL BY

L. Berry

DRILL RIG

CME 75

WEATHER NOTES

Sunny, warm, light breeze

BORING NUMBER

20P-04

SURFACE ELEVATION

LOGGED BY

J. Schmidt

DRILLER

2R Drilling, Inc.

BEGIN DATE

6-30-20

COMPLETION DATE

6-30-20

DRILLING METHOD

8" Hollow-Stem Auger

HAMMER TYPE

140-lb Automatic Trip BOREHOLE LOCATION (Lat/Long or North/East and Datum)

DURING DRILLING

Not encountered

AFTER DRILLING (DATE)

BACKFILLED WITH

Backfilled with cuttings

LOCATION DESCRIPTION

Dumont Dunes Rd, Left of CL

BOREHOLE LOCATION (Offset, Station, Line)

Sta. 135+00 M at er ia l

G ra ph ic s

PROJECT NUMBER

220-070

SHEET

M oi st ur e C on te nt

D E

P T

H ft)

BORING NUMBER

20P-04

D ry

U ni t W ei gh t

(p cf

B lo w s pe r in

R ec ov er y

E

LE

V A

T

IO

N ft)

REVISION DATE

6/30/2021

D ril lin g

M et ho d

C as in g

D ep th

Remarks

S he ar S tr en gt h

(k sf

DESCRIPTION

S am pl e

Lo ca tio n

S am pl e

N um be r

B lo w s pe r fo ot

R Q

D

F F

(F ra ct ur es /F oo t)

PROJECT NAME

CA FTBL Dumont Dunes Road

B

R

S T

A N

D A

R D

-0

LO

G S

A N

D L

A B

.G P

J C

A

LI

F O

R N

IA

Y

E H

L

IB

R A

R Y

Y

E H

V

A P

R

IL

0)

C F

L.

G

LB

/3 0/

Page A-11 of 29

-200 (29% G, 63% S, 8% F)

10'' AGGREGATE BASE.

Poorly graded SAND with SILT and GRAVEL (SP-SM), dense, light brown, dry, fine to coarse GRAVEL, fine and coarse SAND, (ALLUVIUM).

Bottom of borehole at 5.5 ft bgs

This Boring Record was developed in accordance with the CFL-FHWA Geotechnical Technical Guidance Manual (2007) except as noted on the Soil or Rock Legend or below.

TOTAL DEPTH OF BORING

5.5 ft

GROUNDWATER

READINGS

FINAL BY

L. Berry

DRILL RIG

CME 75

WEATHER NOTES

Sunny, warm, light breeze

BORING NUMBER

20P-05

SURFACE ELEVATION

LOGGED BY

J. Schmidt

DRILLER

2R Drilling, Inc.

BEGIN DATE

6-30-20

COMPLETION DATE

6-30-20

DRILLING METHOD

8" Hollow-Stem Auger

HAMMER TYPE

140-lb Automatic Trip BOREHOLE LOCATION (Lat/Long or North/East and Datum)

DURING DRILLING

Not encountered

AFTER DRILLING (DATE)

BACKFILLED WITH

Backfilled with cuttings

LOCATION DESCRIPTION

Dumont Dunes Rd, Right of CL

BOREHOLE LOCATION (Offset, Station, Line)

Sta. 145+00 M at er ia l

G ra ph ic s

PROJECT NUMBER

220-070

SHEET

M oi st ur e C on te nt

D E

P T

H ft)

BORING NUMBER

20P-05

D ry

U ni t W ei gh t

(p cf

B lo w s pe r in

R ec ov er y

E

LE

V A

T

IO

N ft)

REVISION DATE

6/30/2021

D ril lin g

M et ho d

C as in g

D ep th

Remarks

S he ar S tr en gt h

(k sf

DESCRIPTION

S am pl e

Lo ca tio n

S am pl e

N um be r

B lo w s pe r fo ot

R Q

D

F F

(F ra ct ur es /F oo t)

PROJECT NAME

CA FTBL Dumont Dunes Road

B

R

S T

A N

D A

R D

-0

LO

G S

A N

D L

A B

.G P

J C

A

LI

F O

R N

IA

Y

E H

L

IB

R A

R Y

Y

E H

V

A P

R

IL

0)

C F

L.

G

LB

/3 0/

Page A-12 of 29

CR (pH = 9.65, r = 353 ohm-cm, SO4

2- = 641 mg/kg, Cl- = 202 mg/kg)

-200 (24% G, 68% S, 8% F)

12'' AGGREGATE BASE.

Poorly graded SAND with SILT and GRAVEL (SP-SM), dense, light brown, dry, fine to coarse GRAVEL, fine and coarse SAND, (ALLUVIUM).

Bottom of borehole at 5.5 ft bgs

This Boring Record was developed in accordance with the CFL-FHWA Geotechnical Technical Guidance Manual (2007) except as noted on the Soil or Rock Legend or below.

TOTAL DEPTH OF BORING

5.5 ft

GROUNDWATER

READINGS

FINAL BY

L. Berry

DRILL RIG

CME 75

WEATHER NOTES

Sunny, warm, light breeze

BORING NUMBER

20P-06

SURFACE ELEVATION

LOGGED BY

J. Schmidt

DRILLER

2R Drilling, Inc.

BEGIN DATE

6-30-20

COMPLETION DATE

6-30-20

DRILLING METHOD

8" Hollow-Stem Auger

HAMMER TYPE

140-lb Automatic Trip BOREHOLE LOCATION (Lat/Long or North/East and Datum)

DURING DRILLING

Not encountered

AFTER DRILLING (DATE)

BACKFILLED WITH

Backfilled with cuttings

LOCATION DESCRIPTION

Dumont Dunes Rd, Left of CL

BOREHOLE LOCATION (Offset, Station, Line)

Sta. 157+00 M at er ia l

G ra ph ic s

PROJECT NUMBER

220-070

SHEET

M oi st ur e C on te nt

D E

P T

H ft)

BORING NUMBER

20P-06

D ry

U ni t W ei gh t

(p cf

B lo w s pe r in

R ec ov er y

E

LE

V A

T

IO

N ft)

REVISION DATE

6/30/2021

D ril lin g

M et ho d

C as in g

D ep th

Remarks

S he ar S tr en gt h

(k sf

DESCRIPTION

S am pl e

Lo ca tio n

S am pl e

N um be r

B lo w s pe r fo ot

R Q

D

F F

(F ra ct ur es /F oo t)

PROJECT NAME

CA FTBL Dumont Dunes Road

B

R

S T

A N

D A

R D

-0

LO

G S

A N

D L

A B

.G P

J C

A

LI

F O

R N

IA

Y

E H

L

IB

R A

R Y

Y

E H

V

A P

R

IL

0)

C F

L.

G

LB

/3 0/

Page A-13 of 29

R (R-Value = 74)

-200 (8% G, 76% S, 15% F)

12'' AGGREGATE BASE.

SILTY SAND (SM), medium dense, light brown, dry, few fine to coarse GRAVEL, fine and coarse

SAND, ALLUVIUM.

Dense.

Bottom of borehole at 5.5 ft bgs

This Boring Record was developed in accordance with the CFL-FHWA Geotechnical Technical Guidance Manual (2007) except as noted on the Soil or Rock Legend or below.

C

TOTAL DEPTH OF BORING

5.5 ft

GROUNDWATER

READINGS

FINAL BY

L. Berry

DRILL RIG

CME 75

WEATHER NOTES

Sunny, warm, light breeze

BORING NUMBER

20P-07

SURFACE ELEVATION

LOGGED BY

J. Schmidt

DRILLER

2R Drilling, Inc.

BEGIN DATE

6-30-20

COMPLETION DATE

6-30-20

DRILLING METHOD

8" Hollow-Stem Auger

HAMMER TYPE

140-lb Automatic Trip BOREHOLE LOCATION (Lat/Long or North/East and Datum)

DURING DRILLING

Not encountered

AFTER DRILLING (DATE)

BACKFILLED WITH

Backfilled with cuttings

LOCATION DESCRIPTION

Dumont Dunes Rd, Right of CL

BOREHOLE LOCATION (Offset, Station, Line)

Sta. 168+00 M at er ia l

G ra ph ic s

PROJECT NUMBER

220-070

SHEET

M oi st ur e C on te nt

D E

P T

H ft)

BORING NUMBER

20P-07

D ry

U ni t W ei gh t

(p cf

B lo w s pe r in

R ec ov er y

E

LE

V A

T

IO

N ft)

REVISION DATE

6/30/2021

D ril lin g

M et ho d

C as in g

D ep th

Remarks

S he ar S tr en gt h

(k sf

DESCRIPTION

S am pl e

Lo ca tio n

S am pl e

N um be r

B lo w s pe r fo ot

R Q

D

F F

(F ra ct ur es /F oo t)

PROJECT NAME

CA FTBL Dumont Dunes Road

B

R

S T

A N

D A

R D

-0

LO

G S

A N

D L

A B

.G P

J C

A

LI

F O

R N

IA

Y

E H

L

IB

R A

R Y

Y

E H

V

A P

R

IL

0)

C F

L.

G

LB

/3 0/

Page A-14 of 29

50/5"

89 -200 (25% G, 65% S, 10% F)

12'' AGGREGATE BASE.

Poorly graded SAND with SILT and GRAVEL (SP-SM), very dense, light brown, dry, fine to coarse GRAVEL, fine and coarse SAND, ALLUVIUM.

Dense.

Bottom of borehole at 5.5 ft bgs

This Boring Record was developed in accordance with the CFL-FHWA Geotechnical Technical Guidance Manual (2007) except as noted on the Soil or Rock Legend or below.

TOTAL DEPTH OF BORING

5.5 ft

GROUNDWATER

READINGS

FINAL BY

L. Berry

DRILL RIG

CME 75

WEATHER NOTES

Sunny, warm, light breeze

BORING NUMBER

20P-08

SURFACE ELEVATION

LOGGED BY

J. Schmidt

DRILLER

2R Drilling, Inc.

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