NV.FLAP.US50(1).Round Hill Pines Access Road.Geotechnical Report.FINAL.pdf

ROUND HILL PINES ACCESS ROAD

DOUGLAS COUNTY, NV

NV FLAP US50(1)

FINAL Geotechnical Report

Prepared by Federal Highway Administration

Central Federal Lands Highway Division

Geotechnical Services Branch December 2021 ii

SIGNATURE SHEET

Report prepared by: ___________________________________________________________

James M. Arthurs, P.E., Ph.D., Geotechnical Engineer

Report reviewed by: ____________________________________________________________

Todd G. Hansen, P.E., Geotechnical Engineer

Approved for distribution by: ____________________________________________________

Marilyn D. Dodson, P.E., Lead Geotechnical Engineer

Distribution

N:\NV\US50(1)\Geotech\7_FinalDocs

Project Management (PDF only)

Project Development, Lead Designer (PDF only)

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TABLE OF CONTENTS

SECTION ONE - INTRODUCTION

1.1 Background and Location

1.2 Scope and Purpose

SECTION TWO - GEOLOGY AND SEISMICITY

2.1 Regional Geology

2.2 Site Geology

2.3 Regional Seismicity

2.4 Seismic Design Parameters

2.5 Geologic Hazards

SECTION THREE - SUBSURFACE INVESTIGATION

3.1 Subsurface Exploration Program

3.2 Laboratory Testing Program

SECTION FOUR - ANALYSIS & RECOMMENDATIONS

4.1 Geo-profile of Site Materials

4.2 Embankment Recommendations

4.3 Cut Slope Recommendations

4.4 Shrink/Swell recommendations

4.5 Existing Retaining Walls

4.6 Construction Considerations

4.7 Disclaimer/Limitations Clause

SECTION FIVE - REFERENCES

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TABLES

Table 1:- Summary of Nearby Seismic Source Faults Table 2:- Summary of Seismic Parameters Corrected for Site Class C Table 3:- Summary of the Field Exploration Program Table 4:- Summary of Laboratory Index Test Results

FIGURES

Figure 1:- Existing concrete retaining wall Figure 2:- Reinforced embankment section Figure 3:- Embankment drainage detail

PLATES

Plate 1:- Project Location Map Plate 2:- Geology Map Plate 3:- Geotechnical Boring Locations

APPENDICES

APPENDIX A - Field Exploration Program APPENDIX B - Laboratory Test Results APPENDIX C - Photographs APPENDIX D - NDOT Retaining Wall Plans APPENDIX E - Excavation Characteristics of Rock

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Round Hill Pines Access Road NV FLAP US50 (1) December 2021

SECTION ONE - Introduction

1.1 BACKGROUND AND LOCATION

This report presents the results of the geotechnical engineering assessment and provides recommendations for the Round Hill Pines Access Road work to be performed in Douglas County, Nevada. The project proposes to relocate the existing access road for the Round Hill Pines Resort, which is located within the Lake Tahoe Management Unit. A site map is presented on Plate 1 of this report.

The existing Round Hill Pines access road intersects U.S. Highway 50 on a curve with limited site distance. The planned realignment will move this intersection to a tangent portion of Highway 50 to improve site distance and tie the access road into a planned new parking lot. An existing retaining wall supporting the Highway 50 embankment is present at the location of the proposed intersection. The construction will include significant embankment fills. The project will also include paving of the new roadway section, and ancillary construction such as signage and revegetation.

1.2 SCOPE AND PURPOSE

The scope of work included a geotechnical investigation, analysis, and recommendations for embankment construction within the project limits for use in design and construction. This involved several tasks including field reconnaissance, subsurface sampling, laboratory testing, interpretation and correlation of field measurements, and geotechnical engineering analysis.

Specifically, this investigation was conducted to determine the soil profiles in embankment areas and develop recommendations concerning embankment fills, geologic hazards, and construction considerations for the design and construction of fills within the alignment. The stationing in this report is based on the preliminary scoping project plans, dated April 19, 2019.

A pavement investigation was performed as part of this project under separate cover. The pavement report is expected to include recommendations for pavement sections and remediation of any weak subgrade areas. We understand that a hydraulics report is being prepared under separate cover by the CFLHD Hydraulics Engineer. The hydraulic report is expected to include recommendations with regards to roadside drainage including ditches and culverts.

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Figure 1. Existing concrete retaining wall.

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SECTION TWO - Geology and Seismicity

2.1 REGIONAL GEOLOGY

The project area is located near Lake Tahoe in the Carson Range of the Sierra Nevada Mountains, which is within the Cascade-Sierra Mountains Province of the Pacific Mountain System. This region has been shaped by a complex geologic history including marine deposition, granitic intrusion, tectonic uplift, volcanic eruptions, glaciation, and erosion. The oldest rocks in the area are metamorphosed Paleozoic and Mesozoic volcanic and sedimentary rocks intruded by Jurassic and Cretaceous granitic rocks of the Sierra Nevada batholith. During the Tertiary period, rivers passed through the area depositing gravel, sand and silt derived from erosion of the older basement rocks. Volcanism was also widespread during this time, including rhyolitic ash-flow tuffs, followed by andesitic mudflow breccias, and andesite, basalt, and latite flows. Glaciation during the Pleistocene epoch played a major role in shaping the modern landscape by carving valleys and depositing moraines. Faulting has also played a key role in the modern landscape, especially through basin-and-range style faulting which formed the basin in which Lake Tahoe is located.

2.2 SITE GEOLOGY

The site is mapped as underlain by Pleistocene Lacustrine Terrace Deposits (Qlt) and Cretaceous Granodiorite of East Peak (Keg). The lacustrine deposits are described as poorly to moderately sorted silt, sand, and gravel forming broad low terraces 5 to 10 meters above lake level. The granodiorite is described as fine- to medium-grained, well-foliated, equigranular to weakly porphyritic hornblende-biotite granodiorite to quartz monzodiorite. Undivided granite and granodiorite (Kgr) and quartz diorite and diorite (Kqd) are also mapped in the vicinity of the project area. These units are described as fine- to coarse-grained with various compositions and potential origins. A geologic map of the project area is presented in Plate 2.

2.3 REGIONAL SEISMICITY

Numerous seismic source faults are mapped within 40 miles of the project area. The critical active faults to the project site may be found in Table 1 (U.S. Geological Survey, 2019). These faults are generally oriented north-south and located both east and west of the project site. Most of the faults have been active in the Holocene (less than 15,000 years ago) and have slip rates between 0.008 and 0.08 inches per year.

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Table 1. Summary of Nearby Seismic Source Faults

Name Distance from Project Slip Rate Fault Length Time of Last

Deformation

(miles) (inches/year) (miles) (years ago)

Carson Range-Kings Canyon Fault 5.54 0.084 44.12 15,000

West Tahoe Fault 7.03 0.008 to 0.04 31.07 15,000

Indian Hill Fault 7.60 0.005 4.97 15,000

Carson City Fault 8.77 0.008 9.94 15,000

North Tahoe Fault 9.67 0.008 to 0.04 15.53 15,000

Incline Village Fault 9.50 0.008 to 0.04 34.80 15,000

Little Valley Fault 14.70 0.010 10.56 15,000

Mount Rose Fault Zone 15.56 0.077 23.61 15,000

Antelope Valley Fault Zone 20.37 0.008 to 0.04 31.69 15,000

Polaris Fault 22.02 0.008 to 0.04 23.61 15,000

Smith Valley Fault 27.00 0.013 58.41 15,000

Dog Valley 29.91 - - 1,600,000

Singatse Range Fault Zone 38.61 0.005 24.85 130,000 Notes: “-“ indicates data not available. For California faults, slip rates are presented as a range of values.

2.4 SEISMIC DESIGN PARAMETERS

Major structures, such as bridges, are not anticipated to be included as part of this project. If minor structures, such as retaining walls or reinforced soil slopes, are included in the project, the following seismic design parameters should be considered in design. Recommended seismic response parameters for the Round Hill Pines Access Road site design are based on the American Association of State Highway and Transportation Officials (AASHTO) LRFD Bridge Design Specifications, 7th Edition, 2014, and represents horizontal peak ground acceleration (PGA) with 7 percent probability of exceedance in 75 years (approximate 100-year return period). The 1000-year return period uniform hazard spectrum for the approximate center of the project site, located at 38.991341°N latitude and 119.950284°W longitude, was obtained in accordance with the AASHTO ground motion maps.

Based on the material encountered and tested during drilling, the average Standard Penetration Test (SPT) blow count (blows per foot) (ASTM D1586) for the top 100 feet of the soil profile was estimated to be greater than 50 blows per foot. Therefore, the site is classified as Class C according to the site class definitions specified in Table 3.10.3.1-1 of AASHTO. The recommended spectral acceleration coefficient values for probabilistic design are summarized in Table 2.

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Table 2. Summary of Seismic Parameters Corrected for Site Class C

Peak Seismic Ground Acceleration Coefficient, (As) 0.471 Horizontal Response Spectral Acceleration at Period of 0.2 sec, (SDS) 1.144 Horizontal Response Spectral Acceleration at Period of 1.0 sec (SD1) 0.573

Site Factor at Zero-Period of Acceleration Spectrum, (Fpga) 1.0 Site Factor at Short-Period of Acceleration Spectrum, (Fa) 1.0

Site Factor at Long-Period Range of Acceleration Spectrum, (Fv) 1.387

Based on the long acceleration coefficient SD1 value of 0.573, the project site is assigned to seismic hazard Zone 4 in accordance with Table 3.10.6-1 of AASHTO. Seismic hazard zones reflect the variation in seismic risk in different regions needing different requirements for design as depicted in Table 4.7.4.3.1-1 in AASHTO.

2.5 GEOLOGIC HAZARDS

Geologic hazards exist from both the natural environment of the project site and from existing and proposed construction of the bridge. The main geologic hazards that may exist within the vicinity of the project limits include: slope instability and seismic events. In particular, slope instability may occur during construction. This risk is particularly high during the late winter and early spring months, due to snowmelt and high precipitation periods. Risk of slope instability can be managed by limiting the maximum slope of cuts and embankments, conducting earthwork operations during dryer periods, and limiting disturbance areas.

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SECTION THREE - Subsurface Investigation

3.1 SUBSURFACE EXPLORATION PROGRAM

A subsurface investigation targeting the existing retaining wall areas was performed by a Central Federal Lands Highway Division (CFLHD) of the Federal Highway Administration (FHWA) pavement and materials engineer on December 11, 2018. The geotechnical subsurface exploration program consisted of drilling a total of three (3) borings below the existing retaining wall. Standard penetration testing (SPT) and sample collection was performed at 5-foot intervals in the borings.

Boring locations are shown on Plate 3, Geotechnical Boring Locations. Subsurface conditions were logged and representative samples were collected and transported to the CFLHD Materials Laboratory in Lakewood, CO, for physical property testing. Logs of the explorations and laboratory test results are presented in Appendix A and B, respectively. A summary of the field exploration is provided in Table 3.

Table 3. Summary of the Field Exploration Program

EXPLORATION

DESIGNATION

LOCATION/

PURPOSE LAT. LONG. GROUND

ELEVATION

TERMINATION

ELEVATION

EXPLORATION

DEPTH

B-3

100 feet north of south end of existing retaining wall

38.9910 -119.9493 6,302 ft 6,272 ft 30 ft

B-4

250 feet north of south end of retaining wall

38.9915 -119.9491 6,298 ft 6,268 ft 30 ft

B-5

25 feet north of north end of existing retaining wall

38.9919 -119.9490 6,295 ft 6,280 ft 15 ft

Note: The exploration locations were estimated relative to existing features. Elevations were estimated from Google Earth.

3.2 LABORATORY TESTING PROGRAM

Limited laboratory testing was conducted as part of the geotechnical scope of work for this project.

Soil cuttings recovered from the top five feet of Boring B-4 were tested in the laboratory to support the field classifications and to provide an estimate of the engineering characteristics and

Page | 7 mechanical properties of the soil. Laboratory tests included gradation (AASHTO T88), classification (AASHTO M145) and Atterberg limits (AASHTO T89 and T90). When the necessary tests were completed, samples were classified using the Unified Soil Classification System (USCS) and AASHTO soil classification system. A summary of the soil test results is shown in Table 4.

Table 4. Summary of Laboratory Index Test Results

BORING

NUMBER

SAMPLE

DEPTH, ft

PERCENT

SAND

PERCENT

PASSING 200 LL PI USCS AASHTO

B-4 0 - 5 81 18 NV NP SM A-2-4(0)

Visual classification and soil test results indicated a relatively uniform soil profile consisting of silty to clayey sands, classifying as A-2-4 by AASHTO and SM by USCS.

The results of the laboratory tests and grain-size distribution curves are presented in Appendix B.

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SECTION FOUR - Analysis & Recommendations

This section presents analysis and recommendations for embankments, cut slopes, material shrink/swell, and construction considerations for the design and construction of slopes within the alignment. Based on discussions with the project team, the project is likely to consist of conventional embankment construction, although reinforced soil slopes or retaining walls may be employed to limit impacts. Generalized subsurface profiles were developed based on field reconnaissance, surficial visual evaluation, and subsurface investigations.

4.1 GEO-PROFILE OF SITE MATERIALS

Bedrock was encountered at shallow depths during the subsurface exploration. The surficial deposits consist of colluvial and residual soils, and recent lacustrine deposits. The subsurface exploration indicates that the colluvial and residual soils are relatively thin (approximately 5 to 10 feet thick) in areas mapped as underlain by granitic bedrock. The SPT testing indicates that the subsurface materials are medium dense sands, indicating that the deposits are unconsolidated to lightly consolidated and potentially subject to minor consolidation and settlement under loading.

The lacustrine deposits are likely unconsolidated and finer-grained compared to the residual and colluvial soils, and are therefore also subject to a greater degree of consolidation under loading.

The local bedrock consists of weathered to relatively fresh granitic rock.

4.2 EMBANKMENT RECOMMENDATIONS

Construction of embankments is proposed to convey the access road from the intersection with US 50 to the project terminus. Soils in the project area are typically silty sands. The existing embankment fills have been constructed at slopes of approximately 1(V):2(H) and are performing well. We assume that similar materials will be used for the proposed new embankments. Therefore, the new embankments should be constructed with maximum 1(V):2(H) side slopes. The embankments should be keyed into the existing ground and compacted in accordance with the requirements of section 204 of the FP-14.

4.3 CUT SLOPE RECOMMENDATIONS

Expansion of the existing cutslopes is proposed to accommodate roadway design concepts.

Evaluation of existing cut slopes was not performed as part of this scope of work. Based on the mapped geology and limited subsurface exploration, the cut slopes for the project are likely composed of a thin mantle of colluvial and/or residual soils overlying weathered granitic bedrock.

The angle of existing cut slopes in the project area varies from about 1(V):1(H) to about 1(V):2(H).

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Available photos depict the existing cut slopes as generally performing well. Cut slopes for the project will be limited to approximately a 300-foot long section along U.S. 50 and are approximately 15 feet in maximum height. At this location, the existing cut slopes are approximately 1(V):1.5(H). Therefore, the proposed cut slopes should be cut no steeper than 1(V):1.5(H). At this angle, revegetation of the slopes may be challenging. If revegetation is a critical concern, the slopes should be flattened.

4.4 SHRINK/SWELL RECOMMENDATIONS

The proposed roadway construction will require fill slopes or retaining walls to accommodate the proposed roadway template. Minor cut slopes are planned to provide sufficient width for proposed widening of US 50. This section provides guidance to aid in estimating the earthwork balance for the project.

For the purpose of estimating shrink/swell values, silty sands are assumed to be the predominate material located in temporary cut areas. Limited blocks of granitic bedrock may also be encountered. The recommended shrink/swell factors are based on a combination of standard tabled values for common materials in the FLH Technical Guidance Manual (2006) and experience with other CFLHD projects in similar materials.

The clayey sand and sandy clay on-site materials are assumed to swell 10 percent (Swell Factor 1.10) if wasted without tight density control during placement. If the on-site soils are incorporated into embankments with tight density control during placement, a shrink of 10 percent (Swell Factor 0.90) should be used.

4.5 EXISTING RETAINING WALLS

Existing retaining walls are present on the project site. The design of the wall is presented in Nevada Department of Transportation construction plans for Project NH-050-1(024), dated January 25, 2006. These plans depict an existing bin wall present on site prior to construction of a cast-in-place concrete wall. The concrete wall is depicted as supported on drilled shafts, socketed into bedrock. A copy of the retaining wall plans is included in Appendix D. Because the existing walls are supported on deep foundations bearing on rock, settlement of the wall due to additional loading will likely be minimal. Therefore, to reduce construction impacts to US 50, the existing wall may be left in place during embankment construction.

The contrast in fill thickness in front and behind the concrete retaining wall creates a potential for differential settlement. Differential settlement across the wall face of approximately 0.5 inches was calculated using the Schmertmann method with foundation material parameters based on the geotechnical investigation, and assumed material parameters for the proposed embankment fill.

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To reduce the potential for differential settlement to negatively impact the pavement section, the embankment fill above the wall should be reinforced. Reinforcement should consist of Stabilization Geogrid, spaced at 1-foot vertically. The reinforced section should extend vertically from the top of wall to the top of the embankment fill. The reinforcement should extend laterally from either a point 10 feet in front of the retaining wall face or the face of the embankment to 15 feet behind the face of the wall. A sketch of the embankment reinforcement is presented in Figure 2.

Figure 2. Reinforced embankment section.

Only lightweight, hand operated equipment should be used within 2-feet vertically and 5-feet laterally (both in front and behind) of the top of the existing wall to reduce potential damage and displacements. Geotextile and geogrid placement should be in accordance with Section 207;

embankment construction should be in accordance with Section 204.

Paving operations over the reinforced embankment should be delayed two months to allow settlements to occur. The subgrade elevation should be checked and corrected prior to paving.

Alternatively, the contractor can monitor settlement of the embankment on both sides of the wall and begin paving once settlement is substantially complete. The monitoring plan should be submitted for approval by the Geotechnical Engineer prior to initiation of embankment construction.

The existing wall has weep holes to drain the wall backfill. To reduce the potential for the weep holes to introduce water into the embankment fill, a drainage section should be installed in front of the wall. This drainage section should consist of a 6-inch diameter perforated drainage pipe

Page | 11 surrounded by granular fill, encapsulated with separation geotextile. Granular fill should meet the requirements of 703.03(a) and separation geotextile should be Class 1, Type B in accordance with Section 714.01(a). A sketch of the drainage system is shown in Figure 3.

Figure 3. Embankment drainage detail.

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Construction of the embankment should be completed as early as possible in the construction sequence to allow sufficient time for settlement of the fill materials to occur prior to placement of pavement.

4.6 CONSTRUCTION CONSIDERATIONS

The natural soils are potentially variable both laterally and vertically. Depth to and condition of bedrock will strongly impact excavation conditions and settlement potential. Minor cuts are anticipated for this project. For the limited cuts and excavation planned for the project, we do not anticipate difficult excavation conditions for conventional, heavy-duty construction equipment in good working order. Boulders consisting of granitic bedrock are present at the surface within the proposed cut areas. Similar boulders are likely present in the subsurface and may complicate excavations. Rippability of the rock will depend on degree of weathering and joint spacing, which was not evaluated as part of this scope of work. The contractor should mobilize equipment capable of breaking down and handling bedrock materials similar to those exposed in the existing cut slopes. Based on the relatively shallow depth of cuts anticipated for the project, the site rock is expected to be rippable using heavy-duty construction equipment. Pneumatic rams may be required to break up larger boulders into manageable sizes for handling.

The lacustrine soils mapped in the western portion of the project may be loose and saturated. If soft, loose, or saturated materials are encountered at the embankment subgrade elevation, the requirements of Section 208 and 209 of the FP-14 should be followed. If issues related to foundation subgrade stability are encountered during construction, the CFLHD geotechnical engineer should be contacted to provide guidance. A limited quantity (approximately 250 cubic yards) of subexcavation should be included in the contract to be used at the discretion of the Contract Officer.

Special Contract Revisions to FP-14 sections 204 and 207 are attached to this report for construction of the reinforced embankment.

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4.7 DISCLAIMER/LIMITATIONS CLAUSE

The recommendations in this report are based on the data obtained from exploratory borings, field review, and laboratory test results. The results of these explorations and tests represent conditions at the specific locations indicated. Subsurface variations across the site are likely and may not become evident until excavation is performed. The Analysis and Recommendations sections in this report include interpretations and recommendations developed by the Government in the process of preparing the design. These interpretations are not intended as a substitute for the personal investigation, independent interpretation, and judgment of the Contractor.

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SECTION FIVE - References

American Association of State Highway and Transportation Officials (AASHTO). “AASHTO LRFD Bridge Design Specifications.” Seventh Edition, 2014.

Armin, R.A. and John, D.A., 1983, Geologic map of the Freel Peak Quadrangle: Geological Survey, Map I-1424, scale 1:62,500.

Saucedo, G.J., 2005, Geologic map of the Lake Tahoe Basin, California and Nevada: California Geological Survey, Regional Map No. 4, 1:100,000.

U.S. Department of Transportation, Federal Highway Administration (FHWA). (2017). “Federal Lands Highway, Soil Description and Identification Guidelines.”

U.S. Department of Transportation, Federal Highway Administration (FHWA). (2014). “Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects, FP-14.”

Publication No. FHWA-FLH-14-001.

U.S. Department of Transportation, Federal Highway Administration (FHWA). (2008). “Project Development and Design Manual”.

U.S. Geological Survey (2018a). “Quaternary Fault and Fold Database of the United States.”

USGS Earthquake Hazards Program, <http://earthquake.usgs.gov/hazards/qfaults/>

U.S. Geologic Survey (2018b). “U.S. Seismic Design Maps.” USGS Earthquake Hazards Program, <http://earthquake.usgs.gov/designmaps/us/application.php>

APPENDIX A

FIELD EXPLORATION PROGRAM

NV FLAP US 50(1) A-1

APPENDIX A

FIELD EXPLORATION PROGRAM

A.1 INTRODUCTION

The Central Federal Lands Highway Division (CFLHD) Pavements and Materials Section completed a field exploration program for the NV FLAP US50(1), Round Hill Pines Access Road project, on December 11, 2018. The scope of work for the geotechnical field exploration program included a total of three (3) borings located adjacent to the existing retaining wall. The drilling component of the field exploration program was coordinated and observed by CFLHD Pavements and Materials personnel. Two additional borings were advanced on the shoulder of US 50 to evaluate the pavement subgrade. Field exploration locations are illustrated on the “Geotechnical Boring Locations” sheet, Plate 3. Individual boring logs are attached. These logs represent a compilation of field and laboratory data and description of the soil and rock by CFLHD Pavements and Materials personnel. The methods used to conduct the field exploration program are described below. Photos of drilling equipment and field exploration activities are included in Appendix C. All rock and soil samples collected during the field exploration program were transported to the CFLHD Materials Laboratory in Lakewood, Colorado for testing. A summary of the laboratory testing program is provided in Appendix B.

A.2 EXPLORATIONS

Taber Drilling of Sacramento, California, provided drilling services for the soil borings. Boring were completed using a track mounted CME-45 drill rig. Borings were drilled on December 11, 2018. A total of three borings (B-3 to B-5) were completed to depths of 30 feet below ground surface near the existing retaining wall. Two additional borings (B-1 and B-2) were advanced to depths of 5 feet along US 50 to evaluate the pavement subgrade conditions. Borings were drilled and sampled using 4-inch diameter solid-stem augurs and split barrel SPT sampling.

If water was encountered at the time of drilling, field personnel measured water levels in the borings. Fluctuations in the ground water level due to seasonal and climatic effects are expected.

The location and elevation of individual borings were estimated from existing features using Google Earth. Boring locations are listed on individual boring logs and are shown on Plate 3.

A.3 SOIL AND ROCK SAMPLING

Disturbed samples were obtained from the borings in accordance with the Standard Penetration Test (SPT), the procedures of which are detailed in AASHTO T-206. The SPT involves driving a 2-inch outside diameter, 1.375-inch inside diameter split spoon sampler a depth of 18 inches with

NV FLAP US 50(1) A-2

a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the split-spoon sampler through each of the 6-inch increments was recorded. The SPT resistance, or N-value, is defined as the number of blows required to drive the sampler over the second and third 6-inch increments. The N-value provides a means for evaluating the relative density or compactness of cohesionless (granular) soils and consistency or stiffness of cohesive (fine-grained) soils. An energy corrected N-value, N60, is used to standardize the energy levels of the hammer system in the SPT to 60% efficiency. The automatic hammer system employed for the SPT’s on this project is assumed to have an efficiency of 80%. Representative portions of the split-spoon samples obtained in conjunction with the SPT were placed in plastic baggies and transported to the CFLHD Materials Laboratory for testing.

A.4 SOIL AND ROCK CLASSIFICATION SYSTEMS

During the completion of borings, CFLHD Pavements and Materials personnel collected bulk soil and rock samples and prepared field logs of the borings. Soil identification and descriptions, as shown on the field logs, are based on ASTM D2488, a systematic process for identifying and describing individual soil samples by visual and manual means. When sufficient laboratory testing was completed, select samples from borings were classified using the Unified Soil Classification System (USCS) and American Association of State Highway and Transportation Officials (AASHTO) soil classification system. Both the visual soil identification system and the referenced soil classification systems are summarized in the attached Soil Classification Field Reference. Rock samples were classified based on the stratigraphic structure, rock strength, degree of weathering, and other properties. The rock classification system is summarized in the attached Rock Classification Field Reference.

Use primary colors or hyphenated compound primary colors. Use "mottled" or "streaked" if necessary.

4. Color Dry Dry to touch, dusty Moist Damp but no visible water Wet Visible free water

5. Moisture Content

Flat Width/Thickness >3 Elongated Length/Width >3

Flat & Elongated Meets both of the above

Applies to sand, gravel, cobbles and boulders.

Length, width and thickness refer to the greatest, intermediate and least dimensions, respectively.

6c. Particle Shape

N Density N Consistency

Unconfined Compressive Strength qu

(tsf)

Undrained Compressive Strength su

(tsf)

Behavior

0-4 Very Loose 0-1 Very Soft <0.25 <0.125 Extrudes between fingers when squeezed

5-10 Loose 2-4 Soft 0.25-0.50 0.125-0.25 Remolded by light finger pressure

11-30 Medium Dense 5-8 Firm 0.50-1.00 0.25-0.50

Imprinted easily with fingers, remolded by strong finger pressure

31-50 Dense 9-15 Stiff 1.00-2.00 0.50-1.00 Imprinted with considerable finger pressure, indented by finger nail

>50 Very Dense 16-30 Very Stiff 2.00-4.00 1.00-2.00 Barely imprinted by fingers or indented by finger nail

>30 Hard >4.00 >2.00 Not imprinted by fingers or difficult to indent with finger nail

SAND & GRAVEL SILT AND CLAY

3. Consistency and Density:

Angular Sharp edges and relatively plane sides.

Subangular Same as angular with rounded edges.

Subrounded Nearly plane sides but well-rounded corners and edges.

Rounded Smooth curved sides and no edges.

Well-

Rounded Very Smooth surfaces, spherical or ovular, no edges.

6b. Particle Angularity Applies to coarse sand, gravel, cobbles and boulders.

Sieve < #200 Flour or smaller

Fine > #200 to #40 Flour to sugar Medium #40 to #10 Sugar to rock salt Course #10 to #4 Rock salt to pea-sized

Fine #4 to 3/4 in. Pea-sized to thumb Coarse 3/4 in. to 3 in. Tumb to fist Cobble 3 in. to 12 in. Fist to basketball

Boulders > 12 in. Larger than Basketball

Material

Gravel

6a. Particle Size

Silt or Clay

Sand

Particle Size Approximate Scale

Example, fine-grained soil: Lean CLAY with Sand (CL)- stiff, brown, moist, medium plasticity, laminated Example, coarse-grained soil: Silty SAND with Gravel (SM)-medium dense, gray, wet, fine to coarse grained, angular to subangular gravel, weakly cemented Example, fine-grained soil (Long Form):

Clayey GRAVEL with SAND (CL-ML)- loose to soft, dark brownish green to pale brownish gray, wet; fine to medium grained, angular, flat sand; coarse grained, rounded elongated gravel, some chert, trace coarse gravel, and cobbles, medium plasticity, dessicated, weak cementation, low dry strength, rapid dilatancy, moderate HCL reaction, hydrocarbon odor, iron oxide staining, alluvium fill, (Quaternary Alluvium), Additional Description.

1. Group Name (Pg. 3) 9.

2. Group Symbol (Pg. 3) 10.

3. Consistency / Relative Density (Pg. 1) 11.

4. Color (Pg. 1) 12.

5. Moisture (Pg. 1) 13.

6. Particle Size / Shape / Angularity (Pg. 1) 14.

7. Plasticity (Pg. 2) 15.

8. Structure (Pg. 2)

Odor (Pg. 2)

Use the following descriptive sequence when classifying soils, both in the field and when entering data into gINT:

Staining (Pg. 2)

Cementation (Pg. 2) Organics Dry Strength (Pg. 2) Dilatancy (Pg. 2) HCL Rxn (Pg. 2)

Weak Crumbles with little finger pressure Moderate Crumbles with considerable finger pressure Strong Will not crumble with finger pressure

Intact coarse-grained soil

9. Cementation

Nonplastic Thread cannot be rolled at any water content.

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

Medium The 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. The lump crumbles when drier than the plastic limit.

High It takes considerable time kneading and rolling to reach the plastic limit. The thread can be rerolled several times after reaching the plastic limit. The lump can be formed without crumbling when drier than the plastic limit.

Toughness test: Shape the specimen into an elongated pat and rolled on a smooth surface or between the palms into a thread ~1/8”. If the sample is too wet to roll, it should be allowed to dry. Fold the thread and reroll repeatedly until the thread crumbles at a diameter of ~1/8”. This will be near the plastic limit. Note the pressure required to roll the thread near the plastic limit and the strength of the thread. After the thread crumbles, the pieces should be lumped together and kneaded until the lump crumbles. Note the toughness during kneading.

On the basis of observations made during the toughness test, describe plasticity.

7. Plasticity

None No visible reaction Weak Some reaction, bubbles forming slowly Strong Violent reaction, with bubbles forming immediately

13. HCL Reaction 14. Odor 15. Staining None None

Chemical Hyrodcarbon Hyrodcarbon Iron Oxide

Organic

None No visible change Slow Water appears slowly during shaking and does not disappear or disappears slowly during squeezing.

Rapid Water appears quickly during shaking and disappears quickly during squeezing.

12. Dilatancy

1. Mold soil, adding water if necessary, into ~1/2” diameter ball with soft but not sticky consistency.

2. Smooth in palm of one hand with knife blade. Shake horizontally, striking the side of the hand vigorously against the other hand several times. Note the reaction of water appearing on the surface.

4. After Dilatancy has been determined perform the Toughness test (see explanation in #7).

3. Squeeze by closing the hand or pinching the soil between fingers. The reaction is the speed with which water appears while shaking and disappears while squeezing.

None Crumbles into powder with mere pressure of handling.

Low Crumbles into powder with some finger pressure.

Medium Breaks into pieces with considerable finger pressure.

High Cannot be broken with finger pressure, will break between hard surface and thumb.

Very High Cannot be broken between hard surface and thumb.

1. Mold a ball ~1” diameter until it has the consistency of putty, adding water if necessary.

2. From the ball, make at least 3 ½” diameter balls. Allow to air dry.

3. If the specimen contains natural dry lumps, those that are ~1/2” diameter may be used in place of molded balls.

4. Test the strength of the dry balls or lumps by crushing between the fingers.

11. Dry Strength

Stratified Alternating layers > 1/4 inch, note thickness.

Laminated Alternating layers < 1/4 inch, note thickness.

Fissured Contains shears or separations along planes of weakness.

Slickensided Shear planes appear polished or glossy, sometimes striated.

Blocky Cohesive soil can be broken down into harder, angular lumps.

Lensed Inclusion of small pockets of different soils, note thickenss.

Homogeneous Same color and appearance throughout.

Mottled Spots or patches possessing no apparent pattern Varved Distinct laminations of lacustrine sediments predominantly clayey

Desiccated Shrinkage cracks due to dehydration of fine-clayey soil

8. Structure Terms

2. Color For consistency, describe when wet.

Use primary or hyphenated compound primary colors.

1. Rock Type Common classifications; gneiss, granite, shale, etc. A modifier may be necessary to describe a sedimentary rock formed from a combination of soil types, i.e., Silty

SANDSTONE.

V. Coarse Grained > 1/4 in.

Coarse Grained 3/16-1/4 in. Easily distinguished by naked eye Medium Grained 1/16-3/16 in. Can be distinguished by naked eye

Fine Grained Up to 1/16 in. Barley distinguished by naked eye V. Fine Grained Cannot distinguished by naked eye

3a. Grain Size

V. thickly bedded > 3ft Thickly bedded 18 in. - 3 ft Thinly bedded 2-18 in.

V. thinly bedded 3/8- 2 in.

Laminated 3/16- 3/8 in.

Thinly laminated < 3/16 in.

3c. Bedding For Sedimentary Rock

Fresh No visible sign of rock material weathering; perhaps slight discoloration on major discontinuity surfaces.

Slightly weathered Discoloration indicates weathering of rock material and discontinuity surfaces. All the rock material may be discolored by weathering and may be somewhat weaker externally than in its fresh condition.

Moderately weathered Less than half of the rock material is decomposed and/or disintegrated to a soil. Fresh or discolored rock is present either as a continuous framework as corestones.

Highly weathered More than half of the rock material is decomposed and/or disintegrated to a soil. Fresh or discolored rock is present either as a continuous framework as corestones.

Completely weathered (Decomposed)

All rock material is decomposed and/or disintegrated to a soil. The original mass structure is still largely intact.

Residual Soil All rock mass is converted to a soil. The mass structure and material fabric are destroyed. There is a large change in volume, but the volume has not been significantly transported.

4. Weathering

EXAMPLES

GNEISS- Dark gray, moderately weathered, strong. Biotite foliation, low angle, close. Quartz veins, close, low angle, stepped. Primary joint set, close, low angle, tight, moderately weathered, very narrow with rust surface staining and spotty clay infilling, rough planar. (SLIVER PLUME GRANITE) GRANODIORITE- Grey to white, medium grained, slightly weathered, strong, joints are moderate to high angle, very close, rough, open to closed, FE stained joints. Poor Circulation.

SANDSTONE- Tan to reddish brown, fine to medium grained, sub rounded, thinly bedded, moderately weathered, strong, joints are low angle, very close, closed, rough. FE surface staining throughout sample, some organics seen in joint sets.

1 Rock Type (CAPITAL LETTERS) (Pg.1) 6

2 Color (Pg.1) a. Type e. Separation 3 Grain Size or Bedding (Pg.1) b. Stratification f. Infilling & Weathering

4 Weathering (Pg.1) c. Spacing g. Roughness 5 Strength (Pg.1) d. Orientation

Discontinuities (Pg.2)

Miscellaneous (Pg.2) Formation or Unit Name (CAPITAL LETTERS)

Core should be placed in core boxes from left to right, top to bottom. The rock description for each core run should include, in this order:

Angular Show very little wear, grain edges are sharp Subangular Show definite effects of wear, grain edges slightly rounded Subrounded Shows considerable wear , grain edges rounded smooth Rounded Shows extreme wear, grain edges smoothed to broad curves Well-Rounded Very Smooth surfaces, spherical or ovular, no edges.

For Sedimentary Rock 3b. Grain Shape

3d. Structure For Sedimentary Rock

Banded Bedded

Cross Bedded Flow Banded

Foliated Interbedded Laminated Massive

R5 Very strong rock Spec imen requires many blows of geologic al hammer to fracture it. 15,000- 35,000

R2 Weak rock Can be peeled by a pocket knife with difficulty, shallow indentation made by firm blow with point of geologic al hammer. 750- 3,500

R6 Extremely strong rock Specimen can only be chipped with geological hammer. > 35,000

R3 Medium strong rock Cannot be scraped or peeled with a pocket knife, specimen c an be fractured with single firm blow of geological hammer. 3,500-7,500

R4 Strong rock Specimen requires more than one blow of geological hammer to fracture it. 7,500-15,000

R0 Extremely weak rock Indented by thumbnail. 50-150

R1 Very weak rock Crumbles under firm blows with point of geological hammer, can peeled with pocket knife. 150-750

5. Description of Relative Strength/ Hardness

Grade Description Field Identification psi

Core Measurements Recovery = Total length of recovered core / Total length of run RQD = Total length of core pieces > 4 in. / Total length of run (RQD may also be calculated separately for different rock types in one run – be consistent by project.)

RQD, Rock Quality Designation %

Description of Rock Quality

0-25 Very Poor

25-50 Poor

50-75 Fair

75-90 Good

90-100 Excellent

RELATION OF RQD & ROCK QUALITY

Foliation Planar arrangement of textural features, usually applied to schistocity or cleavage Vein A body of minerals intruded into a joint or fault Joint A break of structural origin with no visible displacement

Shear A discontinuity along which sufficient differential displacement has occurred to produce slickensides

Fault Major discontinuity with significant displacement, with gouge or adjacent zone of severely fractured rock

Shear or Fault Zone Band of closely spaced discontinuities along which differential movement has occurred Bedding A layered arrangement within the rockmass predominatly sedimentary rock.

6a. Discontinuities

Lamination Thin beds (<3/8 in.)

Fissile Tendency to break along laminations Parting Tendency to break parallel to bedding, any scale Foliation Segregation and layering of minerals in metamorphic rocks

6b. Stratification Discontinuities

Very Wide Greater than 10 ft Wide 3 – 10 ft.

Moderately Close 1 – 3 ft.

Close 2 in. – 1 ft.

Very Close Less than 2 in.

Perpendicular distance between the planes of the discontinuities.

6c. Spacing Discontinuities

Horizontal (for vertical boreholes) 0° - 5° Low Angle 5°- 35° Moderate Angle 35° - 55° High Angle 55° - 85° Vertical (for vertical boreholes) 85° - 90°

Dip angle of discontinuity should be measured with protractor to perpendicular from core axis (0° is perpendicular, 90° is parallel). To describe range of orientations, use the following terms:

6d. Orientation Discontinuities

6f. Infilling Discontinuities Types of common infilling materials include: clay, calcite, chlorite, iron oxide, gypsum/talc., pyrite, quartz, and sand.

Healed Breaks easily or with difficulty, hairline or seam, usually with infilling.

Closed Seen as a hairline trace, no infilling.

Open Core pieces separated or easily separated, may have staining or mineralization on joint surfaces.

Note: These terms are for core logging, others that describe opening width should be used for outcrop mapping.

6e. Separation Discontinuities

Slickensided Smooth, glassy surface sometime with striations.

Smooth Looks and feels smooth.

Slightly Rough Asperities are distinguishable and can be felt.

Rough Some ridges and steps are evident, asperities are clearly visible, surface feels very abrasive.

Very Rough Near-vertical steps and ridges.

6g. Roughness Discontinuities Large scale – planar, stepped, or undulating. Small scale – use the following terms:

Term % by Volume Some Vesicles 5-25

Highly Vesicular 15-50 Scoriaceous Greater than 50

For volcanics only 7a. Vesicularity 7b. Moisture 7c. Staining 7d. Odor

Damp Iron Oxide None Dripping Hydrocarbon Slight

Dry None Moderate Flowing Strong

Wet

None No visible reaction Weak Some reaction, bubbles forming slowly Strong Violent reaction, with bubbles forming immediately

7e. HCL Reaction

H ol lo w

S te m A ug er

5-4-8 (18" = 100%)

50/4" (4" = 100%)

50/4" (4" = 100%)

50/3" (3" = 100%)

50/0"

(SM), brown to black. TOPSOIL El. 6301 ft 1 ft

Silty SAND (SM), medium dense, brown, moist, medium sand, non plastic to low plasticity.

El. 6297 ft 5 ft Silty SAND (SM), dense, brown, moist, medium sand, non plastic to low plasticity. GRANITE, brown, medium grained, highly weathered to completely weathered, extremely weak rock (R0) to very weak rock (R1).

El. 6295 ft 7 ft Silty SAND (SM), very dense, brown to gray and white, medium sand, non plastic to low plasticity. GRANITE, brown, medium grained, slightly weathered to moderately weathered, extremely weak rock (R0) to very weak rock (R1).

El. 6272 ft 30 ft Bottom of borehole at 30 ft.

Groundwater Depth:

While Drilling: 13 ft / Elev 6289 ft At Completion: --- After Drilling: ---

Notes:

Location measure from existing features. Elevation estimated from Google Earth.

Surface Elevation: 6302 ft Latitude: 38.991° Longitude: -119.9493° Datum: 39.042, 119.954 Date Started: 12/11/18 Date Completed: 12/11/18 Driller/Company: Taber Drilling Hammer Type: 140 lbs Automatic

Drill: CME-45

Logger/Company: Martin Fey/CFLHD

B-3BORING LOG

Sheet: 1 of 1

Project Location: Zephyr Cove, NV

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: Round Hill Pines E le va tio n

(f t)

D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

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50/5" (5" = 100%)

50/4" (4" = 100%)

50/6" (6" = 100%)

50/2" (2" = 100%)

50/1" (0" = 0%)

50/1" (1" = 100%)

Fines = 18%

(SM), dark brown to black, moist, fine sand. TOPSOIL El. 6297 ft 1 ft

Silty SAND (SM), light brown, moist, fine sand, non plastic to low plasticity.

El. 6296 ft 2 ft Silty SAND (SM), brown to gray, moist, medium sand, non plastic to low plasticity. GRANITE, brown to grey, highly weathered to completely weathered, extremely weak rock (R0).

El. 6294 ft 4 ft Silty SAND (SM), very dense, gray and white to brown, medium sand, non plastic to low plasticity. GRANITE, greyish white and brown, moderately weathered to highly weathered, extremely weak rock (R0) to very weak rock (R1).

Seams of clay. Joint filling?

Additional clay seams from 8' to 12'

El. 6268 ft 30 ft Bottom of borehole at 30 ft.

Groundwater Depth:

While Drilling: --- At Completion: --- After Drilling: ---

Notes:

Location measure from existing features. Elevation estimated from Google Earth.

Surface Elevation: 6298 ft Latitude: 38.9915° Longitude: -119.9491° Datum: 39.042, 119.954 Date Started: 12/11/18 Date Completed: 12/11/18 Driller/Company: Taber Drilling Hammer Type: 140 lbs Automatic

Drill: CME-45

Logger/Company: Martin Fey/CFLHD

B-4BORING LOG

Sheet: 1 of 1

Project Location: Zephyr Cove, NV

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: Round Hill Pines E le va tio n

(f t)

D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

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8-9-10 (18" = 100%)

32-50/3" (9" = 100%)

50/2" (2" = 100%)

(SC), brown to black, moist, fine sand, low plasticity.

TOPSOIL

El. 6294 ft 1 ft Clayey SAND (SC), medium dense, brown, moist, fine sand, non plastic to low plasticity. Fill material?

El. 6287 ft 8 ft Silty SAND (SM), dense, brown, moist, non plastic to low plasticity. GRANITE, brown, completely weathered, extremely weak rock (R0).

El. 6284.5 ft 10.5 ft Silty SAND (SM), very dense, brown to gray, moist, non plastic to low plasticity. GRANITE, brown to grey, highly weathered to completely weathered, extremely weak rock (R0) to very weak rock (R1).

El. 6280 ft 15 ft Bottom of borehole at 15 ft.

Groundwater Depth:

While Drilling: 11 ft / Elev 6284 ft At Completion: --- After Drilling: ---

Notes:

Location measure from existing features. Elevation estimated from Google Earth.

Surface Elevation: 6295 ft Latitude: 38.9919° Longitude: -119.949° Datum: 39.042, 119.954 Date Started: 12/11/18 Date Completed: 12/11/18 Driller/Company: Taber Drilling Hammer Type: 140 lbs Automatic

Drill: CME-45

Logger/Company: Martin Fey/CFLHD

B-5BORING LOG

Sheet: 1 of 1

Project Location: Zephyr Cove, NV

20 40 60 80

PL LLWC

N VALUE

20 40 60 80

Project Name: Round Hill Pines E le va tio n

(f t)

D ep th ft)

D ril lin g

M et ho d

Field Blow Count (Recovery)No. Test Results

T yp e

SAMPLE

MATERIAL DESCRIPTION

U. S. DEPARTMENT OF TRANSPORTATION

FEDERAL HIGHWAY ADMINISTRATION

FEDERAL LANDS HIGHWAY DIVISION

F H

W A

B O

R

IN

G L

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APPENDIX B

LABORATORY TEST RESULTS

NV FLAP US50(1) B-1

APPENDIX B

LABORATORY TEST RESULTS

B.1 INTRODUCTION

Laboratory tests for the Round Hill Pines Access Road project were completed on select soil and rock samples recovered for the field exploration program in general accordance with the American Association of State Highway and Transportation Officials (AASHTO) and ASTM testing methods. The laboratory testing program was completed to provide data for engineering studies and to classify the materials into similar geologic groups. The testing program included index tests and geotechnical engineering property tests. The following sections describe the laboratory testing procedures.

B.2 INDEX TESTS

Classification and index laboratory testing included identification by visual and manual means, and tests to determine natural water content, unit weight, grain size distribution, fines content, and Atterberg limits. When sufficient laboratory testing was completed, select samples from borings were classified using the Unified Soil Classification System (USCS) and American Association of State Highway and Transportation Officials (AASHTO) soil classification system. Both the visual soil identification system and the referenced soil classification systems are summarized in the Soil Classification Field Reference in Appendix A. Index test results are presented in the attached laboratory reports. Index tests are generally conducted on disturbed or remolded soil samples.