grte201701_GR 21-20-Geotech Report.pdf

Moose Wilson Phase 1 April 2021

Table of Contents 1-i

Geotechnical Report No. 21-20

Moose Wilson Phase 1

FINAL GEOTECHNICAL RECOMMENDATIONS

WY NPS GRTE 2017(1)

Teton County, Wyoming

April 2021

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Table of Contents i

TABLE OF CONTENTS

1 INTRODUCTION

1.1 Project Description

1.2 Scope and Purpose

2 GEOLOGY

3 SITE CONDITIONS

3.1 Kaufman Creek

3.2 Average Temperatures and Precipitation

4 SUBSURFACE INVESTIGATIONS & LABORATORY TESTING

4.1 Subsurface Investigations

4.2 Subsurface Conditions

4.3 Laboratory Testing & Findings

4.4 Subsurface Conditions at Kaufman Creek

5 DESIGN HAZARDS AT KAUFMAN CREEK

5.1 Scour

5.2 Site Seismicity

5.3 Liquefaction

6 KAUFMAN CREEK FOUNDATION ANALYSES & DESIGN

6.1 Resistance Factors

6.2 Bearing Resistance and Settlement

6.3 Soil Parameters for Abutment Foundation Design

7 GEOTECHNICAL RECOMMENDATIONS

7.1 Footing Size Recommendations –Kaufman creek

8 CONSTRUCTION CONSIDERATIONS

8.1 Material & Aggregate Sources

9 LIMITATIONS

10 REFERENCES

List of Figures ii

LIST OF FIGURES

Figure 1-1 Project Location Map

Figure 1-2 Project Vicinity Map

Figure 2-1 Excerpt from the Geologic Map of Grand Teton National Park, Teton County, Wyoming (Love, et al., 1992)

Figure 3-1 View from the beginning of the Phase 1 project. Note paved driving surface

Figure 3-2 Transition to gravel driving surface at about Station 160+30

Figure 3-3 Looking back at transition from unpaved to paved at about Station 233+00

Figure 3-4 Looking ahead near the end of the Phase 1 project. Road ahead to

Figure 3-5 Road condition of the graveled section during November 2016 site visit

Figure 3-6 Example of sparsely-vegetated, gently rolling to flat terrain near

Figure 3-7 Example of sparsely-vegetated, mildly winding, gently rolling to flat terrain

Figure 3-8 Example of relatively stable low cut

Figure 3-9 Example of road cut over native ground with no formal design

Figure 3-10 Paved portion looking ahead station at approximately 243+00

Figure 3-11 Looking ahead at location of Kaufman Creek

Figure 3-12 Existing Kaufman Creek twin culverts

Figure 3-13 Existing Kaufman Creek culverts inlet side

Figure 3-14 Location of nearest weather reporting stations

Figure 4-1 Location of the TP-06 Test Pit

Figure 4-1 Location of nearest weather reporting stations

Figure 5-1 5-Percent-Damped-Design Response Spectrum

Figure 5-2 Results of Liquefaction Analysis

Figure 6-1 Factored Bearing Resistance Curves

Figure 6-2 Active Earth Pressure, ka, Chart (for ’ = 33o)

LIST OF FIGURES (Continued)

List of Tables iii

LIST OF TABLES

Table 2-1 Geologic Units

Table 3-1 Climate Data Summary - Moose, WY US USC00486428

Table 3-2 Climate Data Summary - Jackson, WY US USC00484910

Table 4-1 Material Types Test Summary

Table 5-1 Summary of Seismic Parameters

Table 6-1 Summary Resistance Factors for Bearing Resistance and Sliding

Table 6-2 Select Bearing Resistance Values

Table 6-3 Recommended Soil Parameters for Abutment & Foundation Design

APPENDICES

APPENDIX A

Boring Location Figures

APPENDIX B

FLH Descriptive Terminology for Boring Logs Boring Log Legend Boring Logs

APPENDIX C

Laboratory Test Reports

Introduction 1

1 INTRODUCTION

This report provides the geotechnical investigation results, analysis, and final foundation recommendations for the Moose Wilson Phase 1 Project in Grand Teton National Park. The beginning of the project is located less than 2 miles north of Teton Village at the Granite Entry Station, which is approximately 13 miles driving distance from Jackson, Wyoming via SR 22 and SR 390, with the end of the project located approximately 3.6 miles ahead on the Moose Wilson Road. The project is also accessible from the north via US 26 from Jackson as indicated in Figure 1-1 Project Location Map, and Figure 1-2 Project Vicinity Map. The Moose Wilson Phase 1 Project is the first of several phases of a larger design effort that will improve the safety and visitor experience along the Moose-Wilson Road (MWR) Corridor. The MWR corridor serves as the primary access route to several key destinations in the area, including Poker Flats, Death Canyon and Granite Canyon Trailheads, Laurence S. Rockefeller Preserve (LSR Preserve), White Grass Dude Ranch and Murie Ranch Historic Districts, and the Sawmill Ponds Overlook.

1.1 PROJECT DESCRIPTION

The Phase 1 project will improve the drivability of the MWR corridor within the project limits. It will consist of rehabilitating the paved portion, paving the unpaved portion, improvements to the Granite Entry Station including improvements to turnouts, and improvements to the Poker Flats Parking Area, and the Granite Canyon Trailhead Parking Lot. Additionally, the culvert at Kaufman Creek will be replaced with an approximately 20 feet wide, 25 feet long, steel girder, single-span, bridge founded on cast-in-place strip footing foundations.

1.2 SCOPE AND PURPOSE

The primary purpose of this report is to provide geotechnical recommendations for the final plan set and information pertinent to relevant construction.

The geotechnical scope of work for Phase 1 included visual reconnaissance, a subsurface exploration program consisting of 12 subgrade or extended subgrade test borings and 9 geotechnical test borings, laboratory soil testing, preparation of a preliminary recommendation memorandum, participation in design team discussions and reviews, and preparation of this report. The geotechnical borings were drilled by a drilling contractor under contract to Western Federal Lands Highway Division (WFLHD). Laboratory tests were completed by the WFLHD at the direction of the WFLHD geotechnical engineer.

The following memorandum was previously prepared for the project by the WFLHD:

Subsurface Investigation Results and Preliminary Recommendations, Moose Wilson Corridor Management Support, GM 30-18, dated December 15, 2018

Preliminary Foundation Recommendations, Proposed Bridge at Kaufman Creek, WY NPS GRTE 2017(1) – Moose Wilson Phase 1, Geotechnical Memo 02-20, dated January 24, This report supersedes the previous memoranda.

Figure 1-1 Project Location Map

Figure 1-2 Project Vicinity Map

Geology 3

2 GEOLOGY

The following discussion is a limited synopsis from Geology of Grand Teton National Park (Edmonds, 1951).

Grand Teton, at approximately 13,775 feet is the highest point of the Teton Range and the second highest peak in Wyoming after Gannett Peak. The mountain is entirely within the Snake River drainage basin, which it feeds by several local creeks and glaciers. The Teton Range is a subrange of the Rocky Mountains, which extend from southern Alaska to northern New Mexico and as such is one of the several outstanding physiographic features of the Middle Rocky Mountains Province. On its west is the Teton Basin, on its east Jackson Hole and to the north and south the range loses itself respectively in the Pitchstone Plateau and the low Teton Pass Mountains adjoining the transverse Snake River Range.

At either end of the narrow belt of peaks of the Tetons the summits attain a maximum altitude of 11,000 feet; these heights increase toward the central portion and culminate in a group of jagged spires of which the highest is Grand Teton.

The major Teton Peaks and the canyons of the east slope are carved in Precambrian crystallines.

At the north and south ends of the range the east slope in part is developed in Paleozoic and Mesozoioc sedimentary rocks. On the west slope the canyons are cut mainly in Paleozoic and Mesozoic sedimentaries and in the Tertiary volcanics of the Pitchstone Plateau at the north end.

The Teton Basin is an intermontane basin drained by the northward flowing Teton River which has cut a gorge in the volcanics lying across the northern portion of the basin. Jackson Hole is a narrow intermontane basin, with the Mount Leidy Highlands and the Gros Ventre Range to the east. On the north are uplands which become the Pitchstone Plateau and at the south end are the Hoback, Wyoming and Snake River Ranges.

The sedimentary rocks exposed in the northern portion of the Teton Mountains range in age from middle Cambrian to early Tertiary. The Paleozoic and Mesozoic part of this section thicken south-south-westward from 8,000 to 10,000 feet to more than 40,000 feet in the area around the southeast corner of Idaho.

The deposition of the thick Paleozoic and Mesozoic sediments was followed by the Laramide deformation in which structural axes were developed lying in a northwest-southeast direction.

This folding was followed by extensive erosion and on the resulting low relief surface the earlier Tertiary volcanics were laid down. However, the details of the relationships of the depositional history following the erosion are confused.

Isolated volcanic remnants scattered through the northern Tetons at various elevations suggest that the Teton region was buried by this material. Other conditions, including apparent dips and erosion surfaces in the volcanics and different times of flows indicate that the Teton block was uplifted while volcanism was still active. Following the uplift of the Teton block erosion produced at least three "peneplains" or "surfaces". On this erosional surface the glaciation of the

4 Geology

Pleistocene occurred, producing all the glacial effects which are present in the mountain regions of the west.

The following discussions are excerpts from The Geologic Map of Grand Teton National Park (Love, et al., 1992). Reference to the geologic map shows that there are three predominant mapped geologic units that the Phase 1 project alignment crosses (or runs adjacent to) as presented in Table 2-1. See Figure 2-1 for the alignment shown over the geologic units.

Table 2-1 Geologic Units

Mapped Symbol Unit Description

Qa Alluvium Gravel & sand & flood plain deposits.

Holocene sedimentary deposit

Qg4 Drift

May contain Precambrian rocks from the Teton Range. Locally may include older glacial deposits on lower eastern slopes of Teton

Range.

Pleistocene sedimentary deposit related to glaciation 4

Qf Alluvial fan deposits

Crudely stratified deposits of boulders, gravel, sand, silt, and clay, generally coarse at the apex and fine at distal margins.

Holocene & Pleistocene sedimentary deposit

Qg3 Drift Till containing moderately weathered granite erratics and capped by loess in many places.

Pleistocene sedimentary deposit related to glaciation 3

Geology 5

Figure 2-1 Excerpt from the Geologic Map of Grand Teton National Park, Teton County, Wyoming (Love, et al., 1992)

Begin Phase 1 Project

Kaufmann Creek

End Phase 1 Project

N

6 Site Conditions

3 SITE CONDITIONS

The project begins with a paved driving surface south of the Granite Entrance Station (Figure 3-

1) and continues up to about Station 160+00 (Figure 3-2) where it changes to a graveled driving surface, and then transitions back to a paved surface at about Station 233+00 (Figure 3-3). The paved portion near the Granite Entrance Station appears to be in fair to good condition but the portion beyond Station 233+00 was considered to be in poor to fair condition. The unpaved segment between the two sections was observed to be rough and in generally poor condition and is known to require frequent maintenance (Figure 3-5 along with others). A blading operation was in progress during our November 2016 site visit. (Note that the observed road conditions were subjective and made at the time of the site visits.) It is our understanding that the Granite Entrance Station improvements will be designed by a Consultant under a separate contract.

Figure 3-1 View from the beginning of the Phase 1 project. Note paved driving surface.

Site Conditions 7

Figure 3-2 Transition to gravel driving surface at about Station 160+30.

Figure 3-3 Looking back at transition from unpaved to paved at about Station 233+00

8 Site Conditions

Figure 3-4 Looking ahead near the end of the Phase 1 project. Road ahead to the right is the entrance to the LSR Preserve.

Figure 3-5 Road condition of the graveled section during November 2016 site visit

Site Conditions 9

The project is located west of the Snake River through often-narrow, somewhat-winding corridors over sparsely vegetated and gently rolling to flat terrain. The project begins at approximate elevation 6350 and gently climbs to approximate elevation 6450 over the length of the project.

The low natural slopes observed along the alignment appeared to be stable with no indication of large-scale instability. Large/tall cuts were not observed. In several locations, we observed low, over-steepened cuts with slope angles nearing 45 degrees from the horizontal and heights up to about 6 feet in height. These cuts appeared to be relatively stable but with some surficial sloughing with deposition on/at the road edge. High fill-side embankments and/or slopes were not observed along the project.

Figure 3-6 Example of sparsely-vegetated, gently rolling to flat terrain near the Granite Trail Head

10 Site Conditions

Figure 3-7 Example of sparsely-vegetated, mildly winding, gently rolling to flat terrain

Figure 3-8 Example of relatively stable low cut.

Site Conditions 11

It appears that the unpaved portion of the road was originally constructed as essentially an at-grade shallow blade cut with no formally designed driving surface (see Figure 3-2, Figure 3-5 through Figures 3-7, as examples) and as such requires periodic and frequent maintenance such as blading out potholes and washboards for smoothness. We observed often-narrow corridors with little to no shoulder width through much of the project.

Formal ditches are not present through much of the project--particularly in the areas with the narrowest corridors. (See Figures 3-9 and 3-10 as examples.) Park personnel reported that none of the driving surfaces were formally designed. We observed no evidence of recent frost heaving through the paved portions of the project and none were reported by Park maintenance personnel.

It is our understanding that the travel widths through the corridor will be maintained under the current project.

Figure 3-9 Example of road cut over native ground with no formal design or ditches providing drainage

12 Site Conditions

Figure 3-10 Paved portion looking ahead station at approximately 243+00

3.1 KAUFMAN CREEK

The Kaufman Creek crossing is located in the graveled section at approximate Station 215+25 as can be seen in Figure 3-11. It is located within the limits of a deposit identified on the geologic map as an alluvial fan deposit (Qf) described as crudely stratified deposits of boulders, gravel, sand, silt, and clay. At present, there are twin 72-inch wide by 48-inch high CMP culverts that are planned to be replaced with a steel girder, single-span bridge supported on spread footings. One test boring from the subsurface investigation was drilled at this location as discussed under Section 4.

Site Conditions 13

Figure 3-11 Looking ahead at location of Kaufman Creek

Figure 3-12 Existing Kaufman Creek twin culverts

Kaufman Creek Crossing

14 Site Conditions

Figure 3-13 Existing Kaufman Creek culverts inlet side

Figure 3-14 Existing Kaufman Creek culverts outlet side

Site Conditions 15

3.2 AVERAGE TEMPERATURES AND PRECIPITATION

The National Oceanic & Atmospheric Administration website (NOAA) showed that there are three weather reporting stations in close proximity to the project as shown in Figure 3-14. Reference to the figure shows that the Moose 1 NNE (WY US USW00004131) and Moose (WY US USC00486428) Weather Reporting Stations are located at Moose (the location of the Park Headquarters) and that the Jackson (WY US USC00484910) Weather Reporting Station is located near Jackson. Data from the Moose 1 and Moose reporting stations are essentially the same or very alike, except that the Moose 1 reporting station provides more complete data by reporting the average total snowfall totals as is discussed below. For that reason, only the data from the Moose and Jackson weather reporting stations are referenced further.

Table 3-1 and Table 3-2 contain a summary of the most recent available climate observation data from the two weather reporting stations described above. The tables show 1) the average maximum and minimum temperatures 2) average monthly precipitation and 3) average monthly snowfall data for the observation period 1981 to 2010. Information in the tables are provided to give prospective bidders from outside the geographical area a relative idea of the local weather conditions. Because the information is not a summary of all possible observations at the reporting stations, it is not intended, nor should it be used, to predict how much precipitation to expect during construction, but is instead intended to show a monthly average based on 30 years of statistical data.

Figure 3-14 Location of nearest weather reporting stations

Jackson, WY US USC00484910

Moose 1 NNE, WY US USW00004131 & Moose, WY US USC00486428

16 Site Conditions

Table 3-1 Climate Data Summary - Moose, WY US USC00486428

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Avg. Daily

Max.

Temp. (F)

26.5 31.3 40.7 50.3 61.2 71.0 80.6 79.5 69.5 55.4 38.2 26.6 52.6

Avg. Daily Min. Temp.

(F)

0.9 3.6 14.0 23.8 32.4 38.4 43.1 41.1 33.3 24.2 14.1 2.4 22.6

Avg. Total Precip.

(in.)

2.58 1.82 1.62 1.49 1.88 1.61 1.29 1.29 1.44 1.47 2.64 2.67 21.80

Avg. Total Snowfall

(in.)

36.9 26.6 15.9 7.4 2.2 0 0 0 0.2 4.8 24.1 44.7 162.8

Notes: Station: MOOSE, WY US USC00486428 Period of Record: 1981 to 2010 Elevation: 6444 ft Coordinates: Lat: 43.6536° Lon: -110.7169°

Table 3-2 Climate Data Summary - Jackson, WY US USC00484910

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual Avg. Daily

Max.

Temp. (F)

28.6 32.7 43.6 53.8 63.5 73.5 82.4 81.3 71.2 57.7 39.3 28.1 54.6

Avg. Daily Min. Temp.

(F)

5.6 7.7 18.6 25.7 31.3 37.3 41.5 39.7 32.2 24.8 16.6 7.3 24.0

Avg. Total Precip.

(in.)

1.23 0.98 1.24 1.28 1.98 1.53 1.26 1.40 1.51 1.28 1.62 1.53 16.84

Avg. Total Snowfall

(in.)

16.0 11.0 7.3 0.5 0 0 0 0 0 0.9 10.6 17.5 66.1

Notes: Station: Jackson, WY US USC00484910 Period of Record: 1981 to 2010 Elevation: 6210 ft Coordinates: Lat. 43.4863o, Lon. -110.7615o

Subsurface Investigations & Laboratory Testing 17

4 SUBSURFACE INVESTIGATIONS & LABORATORY TESTING

Initial reconnaissance along the project occurred in early November 2016 during which time 7 test pits were dug for a preliminary evaluation of the subsurface conditions at various locations along the Moose Wilson corridor. One of the test pits, TP-06, was dug within the Phase 1 project limits located at approximate Station 208+90, about 650 feet south of Kaufman Creek.

A formal investigation effort followed in June 2018 as a more comprehensive effort to characterize the subsurface conditions along the Moose Wilson Road from the beginning of the Phase 1 project near the Granite Entrance Station to the intersection of the Moose Wilson Road and the Teton Park Road (near the Park Headquarters in Moose). That investigation consisted of 35 subgrade test holes and 19 geotechnical deep test holes, not all of which were located within the limits of the current project. Laboratory testing was performed by the WFLHD Materials Testing Laboratory following the investigations. The drilling investigations were conducted under contract to WFLHD by Vine Laboratories Inc. out of Commerce City, Colorado, using a CME 55 truck mounted drill rig with an automatic hammer system using a 140-pound weight over a 30-inch drop. Hole logging and boring log preparation were performed by WFLHD personnel. Additional information and pertinent results of the investigations and subsequent laboratory testing are discussed below.

4.1 SUBSURFACE INVESTIGATIONS

In addition to TP-06 (5-foot-deep test pit), the drilling investigation (test holes or test borings) within the current project limits included 10 subgrade test holes (MWR 2018 SG-19 to MWR 2018 SG-30) and 9 geotechnical test holes (MWR 2018 BH-11 to MWR 2018 BH-19). Subgrade test holes were drilled and sampled to approximately 6.5 feet below ground surface (BGS). Drilling depths in the geotechnical test holes ranged from approximately 20.5 to 56.5 feet BGS with the average of approximately 33 feet BGS. At the time of the borings, 4-inch diameter asphalt cores were obtained from the drilling locations that were paved. The subgrade borings were drilled using a 8-inch outside diameter solid-stem auger with a 10-inch flathead auger tip to acquire bulk samples of the underlying materials. An 8.25-inch (O.D.) hollow stem auger or a 4-inch (O.D.)

downhole hammer casing advancer system was used to advance the geotechnical test holes. All test borings were drilled through the driving surfaces or at the side of the road.

Test pit TP-06 was dug by Park staff using a Deere 710J rubber-tired backhoe. Boring location figures are provided in Appendix A, the boring logs are provided in Appendix B, and laboratory test reports are provided in Appendix C. The location of the test pit is included on the boring location figures.

4.2 SUBSURFACE CONDITIONS

The TP-06 test pit was dug west of the road as shown in Figure 4-1. (Test pit log not provided.)

Exposed soils showed sandy silt with gravel to about 2.6 feet BGS over silty sand with gravel containing granitic cobbles (up to 11 inches) that was encountered to the bottom of the test pit (approximately 5.0 feet BGS). The cobbles were noted to be subangular to angular.

18 Subsurface Investigations & Laboratory Testing

Figure 4-1 Location of the TP-06 Test Pit

The subgrade test hole investigations from the larger investigation effort encountered predominately granular soils consisting of poorly-graded to well-graded gravel or sand with lesser constituent quantities of silt and cobbles, and boulders noted in some of the holes. A layer of silty, clayey sand was encountered in MWR 2018 SG-24 between 2 feet and 3.5 feet BGS and silty, clayey sand was encountered in MWR 2018 SG-25 for the full depth of the boring. Silty, clayey, gravel was encountered in MWR 2018 SG-26 for the full depth and clayey, gravel with sand and cobbles was encountered in MWR 2018 SG-28 for the full depth. The encountered subgrade materials were shown to have relative densities of loose to very dense. The gravel and sand components were described predominantly as subangular to subrounded, with few instances (two) described as subrounded to angular. Angularity of the sand was described as medium to coarse with the majority described as medium or fine to medium. The angularity of the gravel was described predominantly as fine to coarse. Cobbles were measured up to 10 inches with at least one 12-inch boulder encountered. Auger refusal was encountered on cobbles/boulders in several borings that on occasion required repositioning of the hole. Bedrock was not encountered in any of the subgrade test holes. Groundwater was noted in MWR 2018 SG-22 at 5 feet BGS during drilling but was either not measured or not present at completion or following drilling.

The geotechnical test hole investigations encountered primarily granular soils consisting of, poorly-graded to well-graded sand with lesser constituent quantities of silt and gravel and cobbles, and boulders up to 3.5 feet encountered or noted as likely in a few of the holes. Of note is boring MWR 2018 BH-18 in which the primary constituent was shown to be gravel, MWR 2018 BH-19 in

Test Pit TP-06

Subsurface Investigations & Laboratory Testing 19 which the primary constituent in the upper 10 feet was shown to be cobbles, and MWR 2018 BH-16 where a layer of silty, clayey sand with gravel was encountered between 2.5 and 6.5 feet BGS. The relative densities were shown to be medium-dense to very-dense with the exception of MWR 2018 BH-19 where a layer of silty sand with gravel was shown to be very-loose.

Groundwater was noted in MWR 2018 BH-14, MWR 2018 BH-15, MWR 2018 BH-17, MWR 2018 BH-18, and MWR 2018 BH-19. Bedrock was not encountered in any of the geotechnical test holes.

Pavement thicknesses measured during the subgrade investigations ranged from 2.25 inches to

4.0 inches with an average of approximately 3.2 inches. An aggregate base course was either not present or was indistinguishable from the subgrade soils.

4.3 LABORATORY TESTING & FINDINGS

Following the in-field investigations the samples were shipped to the WFLHD for examination by the project Materials and Geotechnical Engineers and representative samples were selected to undergo laboratory tests to determine soil classification and index properties. Laboratory tests included Sieve Analysis (AASHTO T11 & T27), Soil Classification (AASHTO M145), Atterberg Limits (AASHTO T89 & T90), Moisture Content (AASHTO T265), R-Value (AASHTO T190/WL190), and Organic Content (AASHTO T267). Not all listed tests were performed on each tested sample. Test results are included on the boring logs in the test holes and depths where laboratory testing was performed. The laboratory test results are contained in Appendix C.

Laboratory test results showed the materials overall to be predominately granular and having the Unified Soil Classification System Group Symbols (USCS Symbols) and descriptions shown in Table 4-1.

Table 4-1 Material Types Test Summary

USCS Symbol 1 Soil Descriptions

SM Silty sand with gravel

SW-SM Well-graded sand with silt and gravel

SC-SM Silty, clayey sand with gravel

GC Clayey gravel with sand

GC-GM Silty, clayey gravel with sand

GW-GM Well-graded gravel with silt and sand

GP-GM Poorly-graded gravel with silt and sand 1 Unified Soil Classification System

Overall, the fines content in the samples (the amount of material passing the No. 200 sieve) was found to range from 3.5 percent to 35.6 percent. Some samples were found to be non-plastic while others were found to have plasticity indices (PIs) that ranged from 2 (slight plasticity) to 15 (medium plasticity).

20 Subsurface Investigations & Laboratory Testing

If the results are limited to the soils encountered in the upper 1 to 2 feet, the fines content is interpreted to range from approximately 3.5 percent to 28.3 percent and the PI ranging from 6 to 15.

Laboratory tests were conducted to determine Resistance R-Values (R-Values). R-value tests are conducted on laboratory compacted soils or aggregates with a stabilometer and expansion pressure devices to obtain results indicative of performance when placed in the base, subbase, or subgrade of a road subjected to traffic. R-value tests were performed on two samples of subgrade materials (SG-21 and SG-25) that were considered to be representative of the corridor with those tests resulting in R-values of 77 and 55, respectively.

A test was performed to determine organic content on a sample from the MWR 2018 SG-26 test hole. The organic content test determines the quantitative oxidation of organic matter in the soils and gives a valid estimate of organic content. Significant organic content in the subgrade materials can lead to an increase in moisture content and to the possibility of differential settlement issues as the organic material decays over time. Organic content was found to be at

3.65 percent for the sample tested. Maximum acceptable organic contents of borrow materials should be 5 percent. Therefore, the contractor should be prepared to segregate materials with higher, unacceptable organic contents when excavating and placing embankment and other engineered fills.

4.4 SUBSURFACE CONDITIONS AT KAUFMAN CREEK

As discussed earlier, subsurface investigations were performed in June 2018. One of the test borings from the investigations, MWR 2018 BH-14, was drilled near the culvert at the northeast side of Kaufman Creek (approximate Station 215+80) as shown in the Google Earth image provided as Figure 4-1. The boring was drilled from the existing roadway and was advanced to a depth of 38.5 feet bgs. The log for this boring is included in Appendix B.

MWR 2018 BH-14

Design Hazards at Kaufman Creek 21

Figure 4-2 Location of nearest weather reporting stations

Subsurface conditions in the boring were interpreted to consist of loose to medium dense, moist, well-graded sand with silt and gravel in the upper 10 feet (approximately) underlain by a layer of medium-dense, wet, poorly-graded sand with gravel to about 12.5 feet BGS. Below 12.5 feet to approximately 30 feet, a layer of medium-dense, wet, poorly-graded sand with silt and gravel was encountered over medium-dense, wet, silty sand with gravel the extended to the bottom of the boring at 38.5 feet.

Groundwater depth was recorded at 6 feet during drilling, 10.3 feet at completion of drilling, and at 6 feet after drilling, which is likely close to the observed surface elevation of the stream during drilling. We interpret the shallow groundwater conditions to be local to the immediate vicinity of the stream and not widespread over the greater vicinity. The local stream groundwater levels can be lowered by capturing and diverting the stream upslope during construction; thus, minimizing the conditions that would create the potential for heaving or flowing sands during construction.

Wetland areas were not reported in the immediate vicinity.

5 DESIGN HAZARDS AT KAUFMAN CREEK

5.1 SCOUR

Secour elevations were provided by Sven Leon of the WFLHD Hydraulics Group in the Kauffman Creek Bridge TSL Bridge Hydraulics Memo, dated December 11, 2019. Based on the 500-year scour event, abutment shallow foundations are recommended to be set at a bottom elevation of

6415.0 feet.

5.2 SITE SEISMICITY

The procedures outlined in Section 3.10 of the 8th Edition of the AASHTO LRFD Bridge Design Specifications (AASHTO BDS) were followed to characterize the seismic hazard. The seismic hazard at the site and the importance of the proposed bridge dictate the level of seismic analysis that is required for the design. The seismic hazard principles within the AASHTO BDS are that bridges shall be designed to have a low probability of collapse but may suffer significant damage and disruption to service when subject to earthquake ground motions that have a seven percent probability of exceedance in 75 years. Partial or complete replacement may be required

(AASHTO BDS, 2017).

It is important to understand that the subsurface investigation was performed at Kaufman Creek to evaluate the site for culvert replacement and not the construction of a new bridge. Based on the AASHTO procedures, the N60 standard penetration resistance in the top 100 feet of the soil profile at the project site should be evaluated, which is not possible given that the single boring at the site was terminated at 38.5 feet. However, if it is assumed that the soil profile below 38.5 feet is similar to the soil profile above 38.5 feet (i.e., granular soils with a relative density of at least medium dense), then a Site Class of “D” for the site may be recommended. Seismic Design Map information was provided by the USGS to determine the base peak ground acceleration and spectral accelerations at the project site for basement rock, with the spectral accelerations scaled

22 Design Hazards at Kaufman Creek to the Site Class using the site factors recommended by AASHTO to represent the seismic accelerations amplified at the ground surface. The results of this analysis are presented in Table 5-1. It should be noted that the USGS Seismic Design Maps use the 2002 USGS dataset, which is still the dataset referenced by the 9th edition of the AASHTO LRFD BDS.

Table 5-1 Summary of Seismic Parameters

Parameter Value

Site Latitude 43.618765°

Site Longitude -110.789367°

Site Class D

Horizontal Peak Ground Acceleration on Site Class B Rock (PGA) 0.397 g

Horizontal Response Spectral Acceleration at a Period of 0.2 sec on Site Class B Rock (Ss)

0.908 g

Horizontal Response Spectral Acceleration at a Period of 1.0 sec on Site Class B Rock (S1)

0.317 g

Mapped Peak Ground Acceleration Coefficient, FPGA 1.103

Mapped Short-Period Spectral Acceleration Coefficient, Fa

1.137

Mapped 1-sec Period Spectral Acceleration Coefficient, Fv

1.767

Modified Peak Ground Acceleration for Project Site, Site Class D (As)

0.438 g

Modified Horizontal Response Spectral Acceleration at a

Period of 0.2 sec for Project Site, Site Class D (SDS)

1.032 g

Modified Horizontal Response Spectral Acceleration at a

Period of 1.0 sec for Project Site, Site Class D (SD1)

0.559 g

AASHTO Seismic Zone 4

The values in Table 5-1 were used to develop the 5-percent-damped-design response spectrum shown in Figure 5-1 for the project site.

Design Hazards at Kaufman Creek 23

Figure 5-1 5-Percent-Damped-Design Response Spectrum

5.3 LIQUEFACTION

Following the AASHTO BDS procedures, this site was determined to be in Seismic Zone 4.

According to AASHTO, a site in Seismic Zone 4 requires a liquefaction analysis if the groundwater at the site is within 50 feet of the ground surface and there are low plasticity silts and sands within the upper 75 feet that are characterized by corrected standard penetration test (SPT) blow count, (N1)60, is less than or equal to 25 blows/ft in sand and nonplastic silt layers, or the normalized shear wave velocity, Vs1, is less than 660 fps, or a geologic unit is present at the site that has been observed to liquefy in past earthquakes.

It is known that groundwater is present within 50 feet of the ground surface and there are saturated layers of low plasticity sand and/or silt with discrete zones having corrected SPT blow counts less than or equal to 25 blows/ft; therefore, following the AASHTO BDS guidelines, the site should be assessed for liquefaction. (Since these two factors exist, the Vs1 and historic liquefaction were not evaluated for the site.) However, as stated previously, the subsurface investigation was not intended to evaluate for a bridge at this site and was terminated at 38.5 feet, which limited the liquefaction analysis to that depth. Given the nature of the geology at the project location, it is our opinion that the greatest potential for earthquake-induced settlement would occur in the upper 40 feet of the stratum and analyzing this zone would be prudent.

24 Design Hazards at Kaufman Creek

Figure 5-2 Results of Liquefaction Analysis

We performed the analysis for earthquake-induced settlement using empirical methods developed by Youd et al. (2001), Boulanger and Idriss (2006), Cetin et al. (2004), as discussed in the AASHTO LRFD Bridge Design Specifications. Additional empirical methods implemented were those of Tokimatsu and Seed (1987) and Ishihara and Yoshimine (1992). The results of the analysis are presented in Figure 5-2. The analyzed model was created based on the conditions encountered in the MWR 2018 BH-14 test hole and the results of the site seismic analysis discussed in the previous section. The model was setup to run under an assumed magnitude 7.1 earthquake event. As can be seen in the figure, the model predicts the potential for cumulative settlement on the order of about 1 inch) within the zone above approximately 20 feet BGS for the magnitude 7.1 design earthquake event. Within this zone, the Factor of Safety (F.S.) drops slightly below 1.0 at approximately 10 feet bgs and again at about 20 feet bgs. As can be seen in the figure, the F.S. is generally on the order of 2.0 outside of the liquefiable zones.

Kaufman Creek Foundation Analyses & Design 25

6 KAUFMAN CREEK FOUNDATION ANALYSES & DESIGN

This section provides discussion of the geotechnical design parameters for use in design of conventional shallow spread footings at Kaufman Creek.

6.1 RESISTANCE FACTORS

Per Table 10.5.5.2.2-1 of the AASHTO BDS, the resistance factors shown in Table 6-1 are used for Strength Limit States.

Table 6-1 Summary Resistance Factors for Bearing Resistance and Sliding

Method / Soil / Condition

Bearing Resistance b Semi-empirical methods

(Meyerhof, 1957), all soils 0.45

Sliding

Precast Concrete placed on sand 0.90

Cast-in-Place Concrete on sand 0.80 ep Passive earth pressure component of sliding resistance 0.50

As discussed in AASHTO BDS Section 10.5.5.1, all resistance factors for Service Limit States shall be taken as 1.0.

6.2 BEARING RESISTANCE AND SETTLEMENT

Bearing capacity for shallow foundations was calculated using AASHTO BDS Section 10.6.2.4 Settlement Analysis for Service Limit State Design and Section 10.6.3 for Strength Limit State Design. Bearing resistance values for various footing widths are plotted in Figure 6-1. The plotted curves represent the Strength 1 Limit State and the Service 1 Limit State for 1 inch of settlement.

Select point values from Figure 6-1 are presented in Table 6-2. A reduction factor of 0.45 was used for the Strength 1 Limit State factored bearing resistance values. A footing length of 20.3 feet was assumed to develop the plots. For convenience, the Extreme Event Limit State is also plotted in Figure 6-1.

26 Kaufman Creek Foundation Analyses & Design

Figure 6-1 Factored Bearing Resistance Curves

Table 6-2 Select Bearing Resistance Values

B’ (ft) Strength 1 Limit

State, qo (ksf)

Service 1 Limit State, q0 (ksf)

Extreme Event Limit State, q0 (ksf)

6 3.64 4.83 8.09

8 4.31 4.13 9.58

10 4.91 3.67 10.92

12 5.45 3.36 12.11

14 5.93 3.09 13.17

16 6.34 2.97 14.08

18 6.68 2.72 14.85

6.3 SOIL PARAMETERS FOR ABUTMENT FOUNDATION DESIGN

Except for the Passive Lateral Earth Pressure Coefficient (kp), the nominal soil parameters for abutment foundation design are provided in Table 6-3. Per AASHTO 3.11.5.4, kp is reduced by the reduction factor, R, so R*kp, which is also provided in the table. In addition to the values of kp and ka (Active Lateral Earth Pressure Coefficient) presented in the table for level backfill, Figure 6-3 shows graphically the variation of ka for changing fill angles above abutment walls.

Kaufman Creek Foundation Analyses & Design 27

Table 6-3 Recommended Soil Parameters for Abutment & Foundation Design

Description Value

Nominal and Factored Bearing Resistance See Figure 6-1 and Table 6-3

Design Subgrade Soils and Preparation Notes

Poorly graded SAND with gravel to poorly graded SAND with silt and gravel.

Prepare foundation soils per FP-14 Section

Minimum Depth for Frost 4.2 ft

Minimum Footing Elevation for Scour 6415.0 feet

Assumed design depth for bearing, Df 2 ft

Soil Angle of Internal Friction, ’fill 33 degrees

Moist Unit Weight, fill 115 pcf

Active Earth Pressure Coefficient, ka, with backfill sloped at 30o from horizontal (see Figure 6-3) 0.496

Active Equivalent Fluid Pressure (when backfill is sloped at 30o from horizontal) 57.1 psf/ft

Active Earth Pressure Coefficient, ka with level backfill (see Figure 6-3) 0.266

Active Equivalent Fluid Pressure (when backfill is level behind the wall) 30.5 psf/ft

At-Rest Earth Pressure Coefficient, k0 (assumes level backfill behind the wall) 0.455

At-Rest Equivalent Fluid Pressure (assumes level backfill behind the wall) 52.4 psf/ft

Reduced Passive Earth Pressure Coefficient, R*kp (for footing) 6.392

Passive Equivalent Fluid Pressure (for footing) 735.1 psf/ft

Friction angle, , between precast concrete and subgrade 19 deg

Nominal coefficient of sliding, tan , between precast concrete and subgrade 0.34

Friction angle, , between cast-in-place concrete and subgrade 26.5 deg

Nominal coefficient of sliding, tan , between cast-in-place concrete and subgrade 0.50

The above values are unfactored.

1. R*kp derived from AASHTO BDS Figure 3.11.5.4.-1.

28 Kaufman Creek Foundation Analyses & Design

Figure 6-2 Active Earth Pressure, ka, Chart (for ’ = 33o)

Foundation Fill per FP-14 subsection 704.01 should be used at a 1:1 spread-out beneath foundations. Structural Backfill per FP-14 Subsection 704.04 should be used as backfill behind abutment foundation walls and wing walls. Geocomposite sheet drains connected to a perforated footing drain pipe should be installed behind abutment/walls and drained to daylight to ensure adequate drainage. The soil parameters listed in Table 6-3 may be used to determine the lateral earth pressures exerted and sliding resistance of the abutment foundation and wing walls. The parameters listed in Table 6-3 assume a vertical abutment/wall.

Geotechnical Recommendations 29

7 GEOTECHNICAL RECOMMENDATIONS

As noted earlier, formal ditches were not present along much of the project. It is generally the case that the absence of ditches can lead to saturation of the subgrade and loss of roadway support, although direct evidence of this was not observed through the paved sections of the proposed project. Regardless, it is considered good practice to establish positive drainage where possible to reduce future risk of weakening the subgrade.

As stated earlier, we are not aware of frost-heave issues within the project limits and the subsurface investigation and laboratory testing indicated that the subgrade conditions are anticipated to be good. Given that, we do not anticipate subexcavations will be necessary on the project and that the possibility of encountering unsuitable subgrade conditions is low. However, it is still possible that unsuitable subgrade conditions might be encountered as isolated occurrences. If unexpected subgrade conditions are encountered, the project Geotechnical Engineer should be notified to assess the subgrade conditions and to evaluate possible remedies.

7.1 FOOTING SIZE RECOMMENDATIONS –KAUFMAN CREEK

The length of the footings at Kaufman Creek are anticipated to be approximately 20 feet. Based on the bearing resistance and settlement analyses alone, our recommendation is to use cast-in-place strip footings with a minimum effective width of 8.0 feet and maximum bearing pressure, qo, of approximately 4.30 ksf. Footing widths of this size are anticipated to result in total settlement of 1.0 inch, or less, if the specified bearing pressure is not exceeded. It is our understanding that additional checks for sliding, eccentricity and other checks under the appropriate limit states and loading conditions have been performed by the project Bridge Design Team that have resulted in additional bearing pressure and footing size requirements. Refer to the project plan set for final footing size requirements.

30 Construction Considerations

8 CONSTRUCTION CONSIDERATIONS

Conform to Sections 204, 208, and 209 of the FHWA Standard Specifications FP-14 for all excavations.

Bedrock was not encountered in the test borings for the project, so we do not anticipate excavation into bedrock will be required on this project. However, boulders and cobbles were noted in some of the borings and in TP-06 but were not encountered in test boring MWR 2018 BH-14 drilled adjacent to the proposed bridge site. Nevertheless, it is advisable that the contractor be prepared to encounter cobbles and boulders of unknown maximum size during excavation at the proposed bridge at Kaufman Creek.

We recommend planning for OSHA type C soil type designation for excavation safety, unless another soil type designation is warranted by qualified construction personnel. Other large excavations are not anticipated for this project.

8.1 MATERIAL & AGGREGATE SOURCES

Except for a stockpile of soil for manufactured topsoil, there is no Government-provided material source for this project. It is the Contractor’s responsibility to provide approved materials from an available commercial or private source that meet the requirements of the contract when construction materials are needed. Refer to the contract documents for the location of the stockpile of soil to be used for manufactured topsoil.

Per subsection 204.08 of FP-14, all suitable roadway excavation material should be used for embankment construction prior to using borrow materials. Laboratory tests performed on the subgrade materials sampled in the gravel section have indicated that the subgrade soils within the tested limits are suitable for use as unclassified borrow. However, it is incumbent upon the Contractor to ensure that the materials are suitable and processed to meet contract specifications.

Laboratory tests were performed on the samples obtained from the MWR 2018 BH-14 test hole drilled at Kaufman Creek. Based on the tested samples, the material excavated from the Kaufman Creek site is indicated to be suitable for use as unclassified borrow. However, it is again the Contractor’s responsibility to show that the excavated materials meet the contract requirements.

9 LIMITATIONS

This report was prepared to provide subsurface investigation results and geotechnical recommendations for the proposed Moose Wilson Phase 1 Project. Professional judgments and recommendations are presented in this report. They are based partly on evaluation of the technical information gathered and partly on the Geotechnical Team’s general experience with subsurface conditions in the area. It should be noted the borings might not represent potentially unfavorable subsurface conditions away from the boring. The observed water levels and/or conditions indicated on the logs are as recorded at the time of the exploration and described herein. The water levels and/or conditions may vary considerably, with season/time, changes in

Limitations 31 climate, rainfall, and other factors and are otherwise dependent on the duration of, and methods used in, and interpretations made from the exploration program.

If soil conditions are encountered during construction that vary from those discussed in this report, or if the nature of the design or project needs, project stationing, and/or configurations should change, the WFLHD Geotechnical Team should be notified immediately in order to evaluate what effects, if any, the changes have on the recommendations contained in this report. The recommendations presented in this report are applicable only to this specific project. These data are not to be used for other purposes.

Questions regarding this report should be addressed to Robert Kraig, WFLHD Geotechnical Engineer, at (360) 619-7699, or robert.kraig@dot.gov.

32 Limitations

GEOTECHNICAL REPORT NO. 21-20

Moose Wilson Phase 1 Final Geotechnical Recommendations

Project

WY NPS GRTE 2017(1)

Teton County, Wyoming

April 2021

Prepared by: _________________________________________ Robert Kraig, Geotechnical Engineer

Reviewed by: _________________________________________ Eric Lim, Sr. Geotechnical Engineer

Approved by: _________________________________________ Doug Anderson, Geotechnical Team Lead

ERIC J. LIM

Digitally signed by ERIC J. LIM Date: 2021.04.12 11:45:34 -07'00'

DOUGLAS A

ANDERSON

Digitally signed by DOUGLAS A

ANDERSON

Date: 2021.04.13 08:23:32 -07'00'

ROBERT

KRAIG

Digitally signed by

ROBERT KRAIG

Date: 2021.04.13 09:21:24 -07'00'

References 33

10 REFERENCES

Kraig, Robert, Geotechnical Memo 30-18, Subsurface Investigation Results & Preliminary Recommendations, Moose Wilson Corridor Management Study, December 15, 2018

Kraig, Robert, Geotechnical Memo 02-20, Preliminary Foundation Recommendations, Proposed Bridge at Kaufman Creek, WY NPS GRTE 2017(1) – Moose Wilson Phase 1, January 24, 2020

AASHTO LRFD Bridge Design Specifications, 9th Edition, 2020

Love, J.D., John C. Reed, Jr., and Ann Coe Christiansen, (1992), Geologic Map of Grand Teton National Park, Teton County, Wyoming, U.S. Department of the Interior, U.S. Geological Survey, Miscellaneous Investigations Series, Map I-2031

Edmund, R.W., Structural Geology and Physiography of the Northern End of the Teton Range, Wyoming, Augustana College Library Publications, No. 23, 1951, Rock Island, Ill.

Google Earth Pro

Leon, Sven, December 11, 2019, Kaufman Creek Bridge TSL Bridge Hydraulics Memo, dated December 11, 2019, U.S. Department of Transportation, Federal Highway Administration, Western Federal Lands Highway Division.

National Oceanic and Atmospheric Administration (NOAA), National Centers for Environmental Information (2020), Normals Monthly Station Details: https://www.ncdc.noaa.gov/cdo-web/datasets/NORMAL_MLY/stations/GHCND:USC00486428/detail Accessed 1/7/2021;

https://www.ncdc.noaa.gov/cdo-web/datasets/NORMAL_MLY/stations/GHCND:USC00486428/detail Accessed 1/7/2021;

JACKSON, WY US USC00484910 Accessed 1/7/2021

Appendix A Boring Location Figures

(Intentionally blank)

TP-06

Appendix B FLH Descriptive Terminology for Boring Logs

Boring Log Legend Boring Logs

10/04/2018

SOIL CLASSIFICATION CHART

Criteria for Assigning Group Symbols and Group Name Using Laboratory TestsA Group

Symbol Group NameB

COARSE-GRAINED

SOILS

More than 50% retained on No. 200 Sieve

GRAVELS

More than 50% of coarse fraction retained on No. 4 Sieve

Clean GRAVELS Less than 5% fines E

C GW Well-graded GRAVEL D

Cu < 4 and/or C GP Poorly-graded GRAVEL D

GRAVELS with fines More than 12% fines E

Fines classify as ML or MH GM Silty GRAVEL D,F Fines classify as CL or CH GC Clayey GRAVEL D,F

SANDS

Less than 50% retained on No. 4 Sieve

Clean SANDS Less than 5% fines I

C SW Well-graded SAND H

C SP Poorly-graded SAND H

SANDS with fines More than 12% fines I

Fines classify as ML or MH SM Silty SAND F,H Fines classify as CL or CH SC Clayey SAND F,H

FINE-GRAINED

SOILS

50% or more passes the No. 200 Sieve

SILTS and CLAYS Liquid limit less than 50

Inorganic PI > 7 and plots on or above the “A” line J CL Lean CLAY K,L,M PI < 4 or plots below “A” line J ML SILT K,L,M

Organic Liquid limit – oven dried Liquid limit – not dried < 0.75 OL Organic CLAY K,L,M,N

Organic SILT K,L,M,O

SILTY and CLAYS Liquid limit 50 or more

Inorganic PI plots on or above “A” line CH Fat CLAY K,L,M PI plots below “A” line MH Elastic SILT K,L,M

Organic Liquid limit – oven dried Liquid limit – not dried < 0.75 OH Organic CLAY K,L,M,P

Organic SILT K,L,M,Q

HIGHLY ORGANIC

SOILS Primarily organic matter, dark in color, and organic odor PT PEAT A -inch sieve.

B If field sample contains cobbles or boulders, add “with cobbles” or “boulders” or both, to group name.

C Cu = D /D10 Cc = (D )2 / (D10 x D ) D E Gravels with 5 to 12% fines require dual symbols:

GW-GM well-graded GRAVEL with silt GW-GC well-graded GRAVEL with clay GP-GM poorly-graded GRAVEL with silt GP-GC poorly-graded GRAVEL with clay

F If fines classify as CL-ML, use dual symbol GC-GM or SC-SM G If fines are organic, add “with organic fines” to group name.

H I Sand with 5 to 12% fines require dual symbols:

SW-SM well-graded SAND with silt SW-SC well-graded SAND with clay SP-SM poorly-graded SAND with silt SP-SC poorly-graded SAND with clay J If Atterberg limits plot in hatched area, soil is a CL-ML, silty

CLAY.

K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel”, whichever is predominant.

L “sandy” to beginning of group name.

M antly…