GR 9-18 Wallowa Geotech Report.pdf

Wallowa Mountain Loop Road Reconstruction Project April 2018

Table of Contents 1-i

Geotechnical Report No. 9-18

Wallowa Mountain Loop Road Reconstruction Project

FINAL GEOTECHNICAL REPORT

OR WALLOWA 4602(1)

Wallowa County, Oregon

April 2018

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Table of Contents i

TABLE OF CONTENTS

1 INTRODUCTION

1.1 Project Description

1.2 Purpose and Scope

2 GEOLOGY

2.1 Geologic Hazards

2.1.1 Site Seismicity

2.1.2 Liquefaction

3 SITE CONDITIONS

3.1 Average Temperatures and Precipitation

3.2 Scour

4 SUBSURFACE CONDITIONS

4.1 Little Sheep Creek Borings

4.2 Subgrade Borings

5 FOUNDATION ANALYSIS AND RECOMMENDATIONS

5.1 Bridge Layout and Foundation Considerations

5.2 Design Loads and Bearing Resistance

5.3 Design Soil and Geotextile Parameters

5.4 GRS-IBS Layout

6 ALIGNMENT RECOMMENDATIONS

6.1 Cut and FIll Slopes

6.2 Subexcavation

7 CONSTRUCTION CONSIDERATIONS

7.1 Excavation

7.2 Dewatering

7.3 GRS-IBS Construction

8 LIMITATIONS

9 REFERENCES

List of Figures ii

LIST OF FIGURES

Figure 1 – Project Vicinity Map

Figure 2 – Geologic Map of Project Vicinity (Walker, 1979)

Figure 3 – 5-Percent-Damped-Design Response Spectrum for Little Sheep Creek site

Figure 4 – Typical GRS-IBS Cross-Section (Adams, et al. 2011)

Figure 5 – Example Shoulder Stabilization

LIST OF TABLES

Table 1 – Summary of Seismic Parameter

Table 2 – Climate Data Summary

Table 3 – Final Bridge Design Loads

Table 4 – Soil Parameters Used for GRS-IBS Design

Table 5 – Recommended Reinforced Shoulder Stabilization Locations (70% Alignment Stationing)

APPENDICES

APPENDIX A

Site Photographs

APPENDIX B

Boring Location Plans Unified Soil Classification System Field Classifications for Soil and Rock Boring Logs BH16-01, BH16-02, SG16-01 to SG16-11

APPENDIX C

Laboratory Test Reports

APPENDIX D

Little Sheep Creek GRS-IBS LRFD Calculations

Introduction 3

1 INTRODUCTION

This report provides the geotechnical investigation results, analysis, and final foundation recommendations for the Wallowa Mountain Loop Road Project. The project area is located approximately seven miles east of Joseph, Oregon, beginning at the intersection of Highway 350 and Wallowa Mountain Loop Road (County Road 4602) and continuing five miles south along the road to the USFS boundary. The coordinates of the project beginning are approximately 45.3407° N and 117.0745° W and the project terminus coordinates are 45.2711° N and 117.0896° W. The project vicinity is shown in Figure 1 - Vicinity Map.

Figure 1 – Project Vicinity Map

1.1 PROJECT DESCRIPTION

The project involves reconstructing approximately 5 miles of Wallowa Mountain Loop Road. Little Sheep Creek currently crosses the roadway via two 6-foot diameter culverts and one overflow culvert in the flood plain. The culvert crossing will be replaced with a single span bridge. The proposed bridge is planned to be approximately 54-ft long by 28-ft wide single span structure with concrete girders supported on Geosynthetic Reinforced Soil – Integrated Bridge System (GRS- IBS) abutments. Loss of shoulder and raveling of the existing fill slope has occurred at several locations. Shoulder stabilization will be performed to widen and preserve the roadway prism where required. It is planned to rehabilitate the roadway using full depth reclamation.

4 Introduction

1.2 PURPOSE AND SCOPE

The purpose of this report is to provide geotechnical recommendations for bridge foundation and roadway design and construction considerations. The geotechnical scope of work included a visual reconnaissance along the proposed alignment, a subsurface exploration program, laboratory soil index testing, preparation of interim memorandums, participation in bridge foundation selection meetings, and preparation of this report.

The stationing referenced in this report is based on the 70% plan sheets.

Geology 5

2 GEOLOGY

The project is located adjacent to Little Sheep Creek. Overburden materials consist of alluvium of Little Sheep Creek and colluvium from the valley walls. As shown Figure 2, the bedrock in the vicinity is Imnaha Basalt (TBf) of the Columbia River Basalt Group. Walker (1979) describes the basalt as mostly thin to moderately thick basalt flows and minor flow breccia of the Miocene Age (5 to 23 million years ago).

Figure 2 – Geologic Map of Project Vicinity (Walker, 1979)

Wallowa Mtn Loop Road

6 Geology

2.1 GEOLOGIC HAZARDS

Geologic hazards can include active faults, liquefaction and related phenomenon, soft or subsiding ground, strong ground shaking, and landsliding, among other natural hazards. Our search did not discover a published geologic hazard map for the vicinity. Based on the geologic mapping and the subsurface conditions encountered in our borings (discussed later in this report), it is our opinion that the relevant geologic hazards in the site vicinity may include: active faults, liquefaction/lateral spreading, and strong ground shaking. These hazards are discussed further in the Site Seismicity section below.

2.1.1 SITE SEISMICITY

Information from the USGS Quaternary fault and fold database for the United States website was used to locate nearby active faults. The closest active fault is the Wallowa Fault. The eastern mapped terminus is located approximately 5 miles southwest of the bridge site. This normal fault is approximately 56 km in length with a slip rate less than 0.2 mm/yr. The fault is mapped with the most recent movement occurring in the mid to late Quaternary (less than 750,000 years ago). No other faults are mapped within 30 miles of the bridge site (USGS, 2006).

AASHTO LRFD Bridge Design Specifications (7th Edition, 2014, with 2015 and 2016 Interim Revisions) use earthquake design ground motion with a 7 percent probability of exceedance in 75 years, approximately equivalent to a return period of 1,000 years. 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 current AASHTO Specifications are: 1) small to moderate earthquakes should be resisted without significant damage; 2) realistic seismic ground motion intensities and forces should be used in the design; and 3) exposure to shaking from large earthquakes may cause damage to the bridge, but the probability of collapse will be low and the damage will be limited to areas of the structure that are accessible for inspection and repair.

The AASHTO LRFD Bridge Design Specifications (2016) state that a site-specific probabilistic analysis to develop design response spectra shall be used if the site is located within 6 miles of an active fault and studies shall be considered to quantify near-fault effects on ground motions to determine if these could significantly influence the bridge response. The Wallowa fault eastern section appears to be within approximately 5 miles from the bridge sites.

USGS hazard mapping efforts are very comprehensive and include a series of regional workshops to gather input from local geologic experts and to improve seismic source models.

This level of effort cannot be easily duplicated and thus site-specific seismic hazard analyses are generally not justified outside of major projects on life-line routes.

The results of a seismic deaggregation found that the Wallowa fault already contributes significantly to the seismic hazard determined using the USGS hazard maps. Therefore, the higher ground motion due to the proximity of the active fault has already been accounted for in the national ground motion maps. Furthermore, AASHTO states that directivity effects are normally evaluated only for essential or critical bridges having natural periods of vibration longer

Geology 7 than 0.5 s. Therefore, we feel use of the general procedure using the national ground motion maps is appropriate for this project.

The procedures outlined in Section 3.10 of the AASHTO LRFD manual were followed to characterize the seismic hazard. Based on the AASHTO procedures, and the standard penetration resistance in the top 100 feet of the soil profile at the project site, AASHTO seismic Site Class C is recommended for the bridge site.

The U.S. Seismic Design Maps were used to determine the peak ground acceleration and spectral accelerations at the project site based on Site Class B rock. The spectral accelerations were then scaled to Site Class C using the site factors recommended by AASHTO to represent the seismic accelerations based on actual ground conditions. The results of this analysis are presented Table

1. It should be noted that the U.S. Seismic Design Maps website uses the 2002 USGS dataset for the AASHTO 2009 Guide Specifications for LRFD Seismic Bridge Design selection, which is still the dataset referenced by the 2014 AASHTO LRFD BDS.

Table 1 – Summary of Seismic Parameter

Parameter Value

Site Latitude 45.341°

Site Longitude -117.074°

Site Class at Project Site (by Soil Type and Penetration Resistance in Top 100 feet of Soil Profile)

C

Horizontal Peak Ground Acceleration on Site Class B Rock, PGA (g) 0.117

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

0.268

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

0.080

Mapped Peak Ground Acceleration Coefficient, FPGA 1.200

Mapped Short-Period Spectral Acceleration Coefficient, Fa 1.200

Mapped 1-sec Period Spectral Acceleration Coefficient, Fv 1.700

Scaled Peak Ground Acceleration for Project Site, Site Class C, As(g) 0.141

Scaled Horizontal Response Spectral Acceleration at a Period of 0.2 sec for Project Site, Site Class C, SDS(g)

0.322

Scaled Horizontal Response Spectral Acceleration at a Period of 1.0 sec for Project Site, Site Class C, SD1(g)

0.137

AASHTO Seismic Design Category A

8 Geology

The values in Table 1 were used to develop the 5-percent-damped-design response spectrum shown in Figure 3 for the project site.

Figure 3 – 5-Percent-Damped-Design Response Spectrum for Little Sheep Creek site

2.1.2 LIQUEFACTION

Soil liquefaction is a phenomenon in which cohesionless soil deposits below the groundwater table lose a substantial amount of strength due to pore pressure generation resulting from earthquake strong ground shaking (Kavazanjian, 2011). Given the low design peak ground acceleration, dense alluvial soils below the water table, and relatively shallow bedrock, liquefaction is not expected at the site during a design seismic event.

Site Conditions 9

3 SITE CONDITIONS

From the intersection with OR Highway 350, Wallowa Mountain Loop Road crosses Little Sheep Creek and travels up the Little Sheep Creek Valley. The elevation climbs steadily along the roadway, ranging from approximately 4,190 to 4,830 feet elevation. The roadway is located on the lower slope of the valley wall, above Little Sheep Creek. It appears side cast construction was utilized to build the original roadway. Cut and fill slopes are often approaching and at the angle of repose. A shallow failure has occurred in the cut slope at ~STA 143+50. Cut side ditches have generally been infilled with soil, gravel, and debris. Most ditches were dry during site visits;

however, several locations appear to be wet year-round from seeps in the uphill slopes including from approximately STA 93+00 to 106+00 and STA 245+00. Several oversized culverts cross under the roadway. At ~STA 118+70 the top of a fully buried 60-72” culvert was observed. It appears these large culverts were installed as livestock crossings, rather than for drainage.

Vegetation along the roadway consists primarily of evergreen trees with deciduous trees commonly located along the banks of Little Sheep Creek. The understory is comprised primarily of bushes and grasses.

Wallowa County maintenance personnel have removed tree stumps from the pavement/embankment structure several times over the years. The pavement is in fair to poor condition with cracking, rutting, and frost heaves present along the alignment. Details regarding the existing pavement conditions are presented in the Pavement Evaluation and Repair Recommendation Memo, dated August 2, 2017 (WFL, 2017a).

Photos of the site conditions are presented in Appendix A.

3.1 AVERAGE TEMPERATURES AND PRECIPITATION

Table 2 shows the average maximum and minimum temperatures, average monthly precipitation, and average monthly snowfall data for the period from 1931 to 2000 for the Enterprise RS, Oregon (352672) weather station (Western Region Climate Center, 2018).

10 Site Conditions

Table 2 – Climate Data Summary

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

Avg. Max.

Temp. (F)

33.9 40.0 47.3 56.7 65.5 72.3 82.9 82.1 73.3 61.2 45.3 36.5 58.1

Avg. Min.

Temp. (F)

13.9 18.6 23.0 28.9 34.8 39.9 42.8 40.4 35.1 29.1 22.3 17.5 28.9

Avg. Total Precip. (in.)

0.91 0.70 0.99 1.17 1.66 2.08 0.69 0.78 1.01 1.08 1.00 1.02 13.10

Avg. Total Snowfall

(in.)

10.9 7.5 7.0 2.2 0.4 0.1 0.0 0.0 0.0 0.8 4.7 7.9 41.6

Avg. Snow Depth (in.)

2 2 0 0 0 0 0 0 0 0 0 1 0

Note:

1) Period of Record: 12/01/1931 to 04/07/2000.

2) Percent of possible observations for period of record: Max. Temp.: 98.5% Min. Temp.: 98.8%

Precipitation: 99.2% Snowfall: 98.5% Snow Depth: 95.7%.

3.2 SCOUR

The Little Sheep Creek was evaluated by WFLHD hydraulics engineers. Scour elevations were provided by the WFLHD Hydraulics Group in a TSL Bridge Hydraulics Memo Report dated, June 15, 2017 (WFL, 2017b). The recommended abutment scour elevations are 4180.0 feet. The bottom of the bridge structure should be placed at or below this elevation. Please refer to the hydraulics report for more information, including rip rap recommendations.

Subsurface Conditions 11

4 SUBSURFACE CONDITIONS

Thirteen subsurface borings were completed at the site October 26 through 29, 2016. The borings consisted of two bridge borings and 11 subgrade borings. One bridge boring was performed at each proposed abutment location. Subgrade borings were performed at approximately ½ mile increments along the project alignment. The boring location map and boring logs are included in Appendix B. The location of the bridge borings are displayed on the boring location map.

Approximate stationing of the subgrade explorations is provided on the boring logs. Approximate stationing of each boring is provided on the logs. The laboratory test results are presented in Appendix C.

4.1 LITTLE SHEEP CREEK BORINGS

Boring BH16-01 on the west side of Little Sheep Creek encountered medium dense clayey gravel and sand to a depth of 8.5 feet. We interpreted this material to be embankment fill material.

Cobbles and boulders are likely nested in the embankment fill. From 8.5 to 29.6 feet below the ground surface, the borings encountered firm/medium dense to very dense silty gravel with sand, cobbles and boulders which was interpreted to be alluvium. The alluvium contained 1 to 3 feet thick layers of lean clay with sand and gravel and poorly graded sand with gravel. Below the alluvium, slightly weathered medium strong to strong (R3-R4) basalt was encountered to the bottom of the boring at a depth of 50.5 feet. Ground water was encountered at a depth of approximately 11 feet below the ground surface.

Boring BH16-02 on the east side of Little Sheep Creek encountered medium dense/firm to very stiff clayey gravel with sand/lean clay with gravel and sand from the ground surface to approximately 7.5 feet in depth, which we interpret to be embankment fill. Boulders and cobbles could be encountered in this fill. From 7.5 to 10 feet below the ground surface, the boring encountered firm to stiff lean clay with sand which was interpreted to be alluvium. From 10 to 34.5 feet below the ground surface, the boring encountered medium dense to very dense poorly graded and silty gravel with clay, sand, cobbles and boulders also interpreted to be alluvium.

Below the alluvium moderately weathered to fresh, medium strong to strong (R3-R4) basalt was encountered. The boring was terminated at a depth of 74.6 feet. Groundwater was encountered at a depth of 13.5 feet.

Groundwater was measured at 11 and 13.5 feet below the ground surface in borings BH16-01 and -02 at the time of drilling. Although small perched areas of groundwater may be encountered above the adjacent elevation of Little Sheep Creek; the groundwater at the abutments is expected to be within 1 to 2 feet of the elevation of Little Sheep Creek. The groundwater and soil moisture conditions should be expected to fluctuate with the stream levels, precipitation, nearby irrigation, and other seasonal factors.

4.2 SUBGRADE BORINGS

Eleven subgrade borings (SG16-01 to SG16-11) were advanced at approximately 0.5 mile intervals along Wallowa Mountain Loop Road. The borings were advanced to depths ranging from

12 Subsurface Conditions

4.1 to 5.5 feet below the ground surface with a 12-inch diameter continuous flight solid stem auger. Subgrade soils generally consisted of silty/clayey gravel to poorly graded gravel with sand and cobbles which was interpreted to be side cast fill. Groundwater was not encountered in the subgrade borings although there does appear to be locations along the alignment with saturated subgrade conditions.

Foundation Analysis and Recommendations 13

5 FOUNDATION ANALYSIS AND RECOMMENDATIONS

5.1 BRIDGE LAYOUT AND FOUNDATION CONSIDERATIONS

The proposed bridge will be a single span 54-foot long, voided, prestressed slab superstructure.

Based on the site and subsurface information, the site is suitable for Geosynthetic Reinforced Soil

– Integrated Bridge System (GRS-IBS) abutments. GRS-IBS abutments consist of closely spaced layers of geosynthetic reinforcement and compacted granular fill with a segmental retaining wall facing unit (SRWU) to create an abutment and integrated approach for the bridge. A reinforced soil foundation (RSF) is typically constructed as a base, the geosynthetic reinforced soil and block facing is constructed on the RSF, and the bridge deck is supported directly on a bearing bed atop the GRS structure. A typical cross-section through a GRS-IBS abutment is shown in Figure 4.

The system is easy to design and inexpensive to construct. It can be quickly built in variable weather conditions with semi-skilled labor and equipment and can easily be modified in the field.

GRS-IBS is more flexible compared to other foundation alternatives during seismic events. The GRS-IBS system integrates the superstructure into the abutment and approach embankment and thereby eliminates the bump at the end of the bridge that typically occurs with deep foundations.

Based on these considerations, GRS-IBS abutments are the recommended foundation type for this project.

The proposed GRS-IBS abutments will likely bear in the silty gravel layer at the bridge site.

Excavation at the bridge site will encounter very dense alluvial soils and may be difficult and require large equipment. Seeps and layers of running sand could be encountered. Cobbles and boulders may be encountered. Excavation of boulders may result in subgrade voids that will require replacement with foundation fill or choker material to provide a level subgrade.

Figure 4 – Typical GRS-IBS Cross-Section (Adams, et al. 2011)

14 Foundation Analysis and Recommendations

5.2 DESIGN LOADS AND BEARING RESISTANCE

WFLHD Structures Group, provided the bridge foundation loads per abutment via email on April 2, 2018 summarized in Table 3.

Table 3 – Final Bridge Design Loads

Load Type Unfactored Load (kips)

Service I Limit State Strength I Limit

State Load

Factor (γ)

Factored Load (kips)

Load Factor

(γ)

Factored Load (kips)

Dead load of superstructure and substructure (DC)

242.5 1.0 242.5 1.25 303.1

Dead load of wearing surface (DW)

36.2 1.0 36.2 1.50 54.3

Vehicular live load (LL) 158.2 1.0 158.2 1.75 276.8 Total 436.9 - 436.9 - 634.2

The superstructure will be set directly on top of the beam seat of the GRS-IBS abutment. The bearing bed reinforcement under the beam seat consists of closely spaced reinforcement to shed the loads. The calculated service limit state and strength limit state bearing loads at the top of the GRS-IBS abutment were 3.4 ksf and 5.9 ksf, respectively. These are within the typical allowable values of 4 ksf and 6 ksf, respectively. This is based on a recommended minimum beam seat width of 4 feet.

5.3 DESIGN SOIL AND GEOTEXTILE PARAMETERS

Table 4 shows the soil parameters used in the GRS-IBS analysis. The bottom of the reinforced soil foundation (RSF) for the GRS-IBS will bear at elevation 4180 feet on the project datum. This is below the upper layers of clayey gravel and clay encountered in the subsurface investigation borings. The RSF will bear on the underlying silty gravel or poorly graded gravel layer.

Table 4 – Soil Parameters Used for GRS-IBS Design

Property Units

Foundation Soil

Retained Soil

Reinforced Soil

RSF

Soil

Unit Weight pcf 130 120 125 125

Friction Angle deg 42 30 38 38

Cohesion pcf 0 0 0 0

Maximum Particle Size in. - - 1.5 -

The design was completed assuming the geotextile will be a woven geotextile with an ultimate biaxial tensile strength of at least 4800 lb/ft and tensile strength at 2 percent strain of at least 960 lb/ft.

Foundation Analysis and Recommendations 15

5.4 GRS-IBS LAYOUT

The bridge layout was dictated by the hydraulic conditions in order to provide adequate clearance across the full channel width and provide adequate embedment of the foundations for scour protection.

The height of the GRS-IBS with SRWU facing (measured from the beam seat to the scour elevation) will be approximately 15.2 feet at Abutment 1 and 17.4 feet at Abutment 2. These heights are the approximate since the bridge deck will have a 4 percent superelevation. The reinforced soil foundation (RSF) will extend 2.5 feet below the base of the GRS-IBS abutment.

The GRS-IBS abutment will be 39.1 feet wide and the wing wall will extend 15 feet back at a 90-degree angle from the abutment face. The RSF limits will extend 2.5 feet horizontally outside the limits of the facing.

The main geotextile reinforcement lengths in the GRS-IBS will be 10 feet in length for all abutments. The main reinforcement layers are installed between subsequent layers of SRWU blocks with a vertical spacing not exceeding 8 inches. The bearing bed zone, directly below the beam seat, will include 5 additional geotextile layers at mid-block height, each 6 feet in minimum length, resulting in vertical spacing no greater than 4 inches between subsequent layers.

The integrated approach zone will include 2 layers of geotextile reinforcement evenly spaced 8 inches vertically starting at the bottom of the beam elevation to the provide a seamless transition from the approach fill to the bridge deck. Each layer wraps back behind the end of the beams with a 4-foot-long tail.

GRS-IBS abutments using CMU blocks typically specify that the top 3 rows of hollow blocks are filled with concrete and rebar to tie them together. Since this project is specified for SRWUs with shear connectors, and grouting of SRWU units is more difficult to perform depending on the manufacturer’s void shape, it is our opinion that grouting the upper 3 rows is not necessary on this project. Half height caps should be used and a polyurethane construction adhesive used to bond them to the top of the abutments and wingwalls.

16 Alignment Recommendations

6 ALIGNMENT RECOMMENDATIONS

6.1 CUT AND FILL SLOPES

The existing cut slopes are generally near the angle of repose. Steepening cut slopes within the project area will generally lead to unstable conditions; therefore, cut slopes should remain at angles similar to the existing cut slopes and should not be steepened.

Fill slopes should be constructed to 1V:2H where possible and may be constructed to 1V:1.5H where a flatter slope would extend beyond the right of way. Slopes steeper than this will likely require shoulder stabilization, a retaining wall, or rock embankment. An examples of shoulder stabilization is provided in Figure 5.

Figure 5 – Example Shoulder Stabilization

Recommended locations of reinforced shoulder stabilization have been developed based on a review of the cross sections and site visits. Generally, reinforced shoulder stabilization is recommended at locations where the paved width of the roadway is less than 21 feet and in some locations where the paved width is less than 22 feet. Table 5 presents approximate recommended reinforced shoulder stabilization locations. It is appropriate for the CO to field fit the exact start and end locations of the stabilization. It is recommended to use biaxial geogrid reinforcement.

Alignment Recommendations 17

Table 5 – Recommended Reinforced Shoulder Stabilization Locations (70% Alignment Stationing)

Beginning Station

Ending Station Alignment Length (ft)

Reinforcement Length (ft)

16+25 18+50 225 7

21+25 23+50 225 7

97+25 98+50 125 7

134+50 135+75 125 7

145+25 147+25 200 13

184+00 184+75 75 7

215+00 216+50 150 7

221+25 223+25 200 7

229+25 233+75 450 7

241+25 242+50 125 7

249+75 252+75 300 7

267+75 269+50 175 7

6.2 SUBEXCAVATION

Areas recommended for subexcavation due to frost action and/or pavement distress have been identified in the WFL Pavement Evaluation and Repair Recommendation Memo, dated August 2, 2017 (WFL, 2017a). It is recommended to overexcavate 24-inches below the subgrade level and replace with Select Granular Backfill. Areas of subexcavation should be lined with a separation geotextile. The subexcavations should be daylighted or include underdrains to provide drainage and avoid a “bathtub” type effect.

18 Construction Considerations

7 CONSTRUCTION CONSIDERATIONS

7.1 EXCAVATION

The proposed GRS-IBS abutments will likely bear in the silty gravel layer at Little Sheep Creek.

Cobbles and boulders may be encountered during excavation and should be expected.

Excavation will be difficult and may require very large equipment and/or hydraulic breakers.

Excavation of boulders may result in subgrade voids that will require replacement with foundation fill or choker material to provide a level subgrade prior to construction of the RSF.

Excavation and road work along the alignment may encounter buried obstructions such as tree stumps. County personnel have indicated they have removed several large stumps that have “floated” up through the roadway over the years (including in the past few years). The contractor should be prepared to encounter buried stumps along the alignment. If any stumps are encountered, they should be removed and the resulting void should be backfilled with suitable embankment material.

Obstructions were also noted within the pavement structure, including a several inch-long piece of metal (see Appendix A, photo A-9). The contractor should be prepared to encounter, and remove if necessary, such obstructions during construction.

7.2 DEWATERING

The elevation of the bottom of the RSF is 4177.5 feet. This elevation is well below the creek surface elevation. The silty gravel layer at the RSF bearing elevation has a relatively high permeability and it is likely the excavations will require dewatering. If the excavation is inundated with water, dewatering is required so the backfill can be placed and compacted in the dry. The soils encountered in the borings will cave if left unsupported when excavations extend below the groundwater table.

7.3 GRS-IBS CONSTRUCTION

The fundamental component of the GRS-IBS system is closely spaced layers of geotextile reinforcement with well-compacted granular backfill. Careful attention should be given to the installation of the first row of blocks. Since all other courses of block are built off the first row, it is essential to ensure that the bottom row is level and even for construction. If larger rock is used in the RSF, a choker material should be used to provide a leveling pad for the first row of SRWUs.

It is highly recommended that the contractor reviews the following resources that provide further details on successful construction of GRS-IBS abutments.

FHWA provides a GRS-IBS construction video located at the following website:

http://www.fhwa.dot.gov/everydaycounts/technology/grs_ibs/multimedia.cfm

This construction video also can be viewed on the FHWA's YouTube channel at:

https://www.youtube.com/watch?v=w_5WFoAdoUw

Construction Considerations 19

The construction video follows the guidance outlined in the GRS-IBS Implementation Guide, FHWA-HRT-11-026, dated January 2011, which is available at the following website:

http://www.fhwa.dot.gov/publications/research/infrastructure/structures/11026/index.cfm

20 Limitations

8 LIMITATIONS

This report was prepared to provide subsurface investigation results and geotechnical recommendations for the proposed Wallowa Mountain Loop Road Reconstruction 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 borings. The observed water levels and/or conditions indicated on the logs are as recorded at the time of the exploration.

The water levels and/or conditions may vary considerably, with season/time, changes in 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 design loads, project stationing, and/or configurations 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 site. These data are not to be used for other purposes.

Questions regarding this report should be addressed to Evan Garich, WFLHD Geotechnical Engineer, at (360) 619-7824, or evan.garich@dot.gov.

22 References

9 REFERENCES

AASHTO LRFD Bridge Design Specifications, Seventh Edition (2014 with 2015 and 2016 interim revisions) American Association of State Highway and Transportation Officials, Washington, D.C.

U.S. Geological Survey, USGS Earthquake Hazards Program website, Unified Hazard Tool, Dynamic: Conterminous US 2008 (v3.3.1) Edition, https://earthquake.usgs.gov/hazards/interactive/ accessed September 27, 2017.

U.S. Geological Survey, USGS Earthquake Hazards Program website, U.S. Seismic Design Maps, http://earthquake.usgs.gov/designmaps/us/application.php, accessed September 27, 2017.

U.S. Geological Survey, 2006, Quaternary fault and fold database for the United States, accessed September 27, 2017, from USGS web site: http://earthquakes.usgs.gov/hazards/qfaults/ .

Walker, GW (1979), Reconnaissance Geologic Map of the Oregon Part of the Grange

Western Federal Lands (2017a), Pavement Evaluation and Repair Recommendation Memorandum, Wallowa Mountain Loop Road Reconstruction, Stephen Henry, August 2, 2017.

Western Federal Lands (2017b), Little Sheep Creek Bridge TSL Bridge Hydraulics Memo, Wallowa Mountain Loop Road, Sven Leon, June 15, 2017.

Western Regional Climate Center (2018), Cooperative Climatological Data Summaries, Enterprise RS, Oregon (352672): https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?or2672, accessed March 27, 2018.

Appendix A – Site Photographs

Photo A‐2, Little Sheep Creek facing upstream from roadway.

Photo A‐1, Beginning of project from intersection with OR 350. Little Sheep Creek crosses under roadway at visible person.

Photo A‐4, Facing downstation toward Little Sheep Creek and OR 350 intersection.

Photo A‐3, Little Sheep Creek, facing downstream from roadway.

Photo A‐6, Seep and ponded water in cut side ditch, ~STA 100.

Photo A‐5, water in ditch, ~STA 106.

Photo A‐8, One of several locations at which the County has removed tree stumps from the roadway embankment. ~STA 72.

Photo A‐7, Buried culvert at ~STA 188+70. Top of culvert is exposed adjacent to roadway.

Photo A‐10, View of alignment and shoulder.

Photo A‐9, Metal in roadway.

Photo A‐12, View of alignment.

Photo A‐11, View of alignment and shoulder.

Photo A‐13, View of alignment and shoulder.

Photo A‐14, View of alignment and shoulder.

Photo A‐15, Cut slope failure at ~STA 143+50.

Appendix B – Borehole Location Plan Boring Logs

FIGBRIDGE BORING LOCATION PLAN

Wallowa Mountain Loop Road Project

WALLOWA COUNTY, OREGON

Project No.

Scale:

File Name:

Date:

OR_WALLOWA_4602(1)

N.T.S

JULY 14, 2016

Western Federal Lands Highway Division 610 East Fifth Street Vancouver, WA 98661

N

SOIL DESCRIPTIVE TERMINOLOGY

CONSISTENCY OF COHESIVE SOILS

SPT N-Value (blows/ft) Consistency Field Identification

0 - 1 Very Soft Easily penetrated several inches by first

2 - 4 Soft Easily penetrated several inches by thumb

5 - 8 Firm Moderate effort required to penetrate several inches by thumb

9 - 15 Stiff Readily indented by thumb but penetrated only with great effort

16 - 30 Very Stiff Readily indented by thumbnail

> 30 Hard Indented with difficulty by thumbnail

RELATIVE DENSITY OF

COHESIONLESS SOILS

SPT N-Value (blows/ft) Relative Density

0 - 4 Very Loose

5 - 10 Loose

11 - 30 Medium Dense

31 - 50 Dense

> 50 Very Dense

PARTICLE SIZE

Term Sieve Size Boulder > 12” (>300mm)

Cobble 3” - 12” (75mm - 300mm)

Gravel – coarse ¾” - 3” (19mm - 75mm)

Gravel – fine #4 - ¾” (4.75mm - 19mm)

Sand – coarse #10 - #4 (2.00mm - 4.75mm)

Sand – medium #40 - #10 (0.425mm - 2.00mm)

Sand – fine #200 - #40 (0.075mm - 0.425mm)

Silt & Clay < #200 (<0.075mm)

MOISTURE CONTENT

Dry Dusty, dry to the touch

Moist Damp, but no visible free water

Wet Visible free water, saturated, over optimum

ROCK DESCRIPTIVE TERMS

ROCK WEATHERING

Field Identification Term Crystals are bright. Discontinuities may show some minor surface staining.

No discoloration in rock fabric. Fresh

Rock mass is generally fresh. Discontinuities are stained and may contain clay. Some discoloration in rock fabric.

Slightly Weathered

Significant portions of rock show discoloration and weathering effects.

Crystals are dull and show visible chemical alteration. Discontinuities are stained and may contain secondary mineral deposits.

Moderately Weathered

Rock can be excavated with geologist’s pick. All discontinuities exhibit secondary mineralization. Complete discoloration of rock fabric. Surface of core is friable and usually pitted due to washing out of highly altered minerals by drilling water.

Highly Weathered

Rock mass is completely decomposed. Original rock “fabric” may be evident. May be reduced to soil with hand pressure. Decomposed

DISCONTINUITY SPACING ROCK QUALITY DESIGNATION (RQD)

Spacing (in) Spacing Term RQD % Designation < 2.5 Very Close 0 - 25 Very poor

2.5 – 8 Close 25 - 50 Poor 8 – 24 Moderately close 50 - 75 Fair 24 – 80 Wide 75 - 90 Good

> 80 Very Wide 90 - 100 Excellent (RQD is the percent of a core run with intact lengths greater than 4 inches excluding breaks caused by drilling.)

INTACT ROCK STRENGTH

Field Identification UCS (psi) Hardness Term Indented by thumbnail. 35 - 150 Extremely Weak (R0) Crumbles under firm blows with point of geological hammer, can be peeled by a pocket knife. 150 - 725 Very Weak (R1)

Can be peeled by a pocket knife with difficulty, shallow indentations made by firm blow with geological hammer.

725 – 3,500 Weak (R2)

Cannot be scraped or peeled with a pocket knife, specimen can be fractured with a single blow of geological hammer.

3,500 – 7,000 Medium Strong (R3)

Specimen requires more than one blow of geological hammer to fracture it. 7,000 – 15,000 Strong (R4)

Specimen requires many blows of geological hammer to fracture it. 15,000 – 36,000 Very Strong (R5)

Specimen can only be chipped with geological hammer. > 36,000 Extremely Strong (R6) (UCS – Unconfined Compressive Strength)

11-9-7

6-8-13

5-6-6

5-3-8

3-2-5

4-5-13

12-21-22

26-41-43

48-50/4¾"

Asphalt Concrete (0.2 ft thick) Clayey GRAVEL with sand, medium dense, brown to gray, moist, fine to coarse, subrounded to subangular, homogeneous. Fill.

Lean CLAY with gravel and sand, firm, dark gray, moist, fine to coarse subangular clasts, low plasticity, homogeneous.

Alluvium.

Silty GRAVEL with sand, medium dense to dense, brown, wet, fine to coarse, subrounded to subangular, homogeneous. Alluvium.

Poorly graded SAND with gravel, dense, light brown, wet, fine to coarse, rounded, homogeneous. Alluvium.

Silty GRAVEL with sand, very dense, brown, wet, fine to coarse, subrounded to subangular, homogeneous, with cobbles, possible boulders. Alluvium.

Boring extended from 20 to 29½' with HQ coring methods, but actual bedrock not encountered until 29½'.

Some clay at 19'.

Run 1: 1:42-2:12 BASALT, white to dark gray, very fine grained, slightly weathered, medium strong (R3). Discontinuities are closely spaced and in fair condition, CR = 72%, RQD = 10%, FF = 2.2, RCT = 30 minutes, joints and fractures ranges from 15° to 45° from assumed horizontal.

Run 2: 2:25-2:50 BASALT, gray, very fine grained, slightly weathered, medium strong (R3). Discontinuities are very closely spaced and in fair condition, CR = 100%, RQD = 33%, FF = 2.4, RCT = 25 minutes, joints and fractures range 30° from assumed horizontal.

Run 3: 3:00-3:10 BASALT, gray, very fine grained, slightly weathered, medium strong to strong (R3-R4). Discontinuities are closely spaced and in fair condition, CR = 100%, RQD =

0.2

8.5

11.0

15.0

16.0

29.6

30.5

35.5

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 45° 20' 26.35" (45.340653°)

LONGITUDE (DEGREES): W -117° 4' 27.26" (-117.074238°)

D E

P T

H ft

Sheet 1 of 2

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 50.5'

LIQUID LIMIT

RQD (%)

AFTER DRILLING

Rock / Soil Core

Split Spoon

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

8" hollow-stem auger to 29.6'. HQ3 from 29.6' to 50.5'.

11+20, 10R

0.0

4.0

8.0

12.0

16.0

20.0

24.0

28.0

32.0

36.0

40.0

NOTES:

BORING BH16-01

COMPANY:

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SK Geotechnical LOGGER: Brandon Western

Cloudy

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Erik Hollibaugh

WEATHER:

PROJECT: OR WALLOWA 4602(1)

Automatic

WATER CONTENT (%)

10.7'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: Diedrich D120

D E

P T

H ft

10/26/2016

S A

M P

LE

R

10/26/2016

STATION, OFFSET:

PLASTIC LIMIT

14%, FF = 4, RCT = 10 minutes, joints and fractures range 30° from assumed horizontal.

Run 4: 3:15-3:20 BASALT, gray, very fine grained, slightly weathered, medium strong (R3). Discontinuities are closely spaced and in fair condition, CR = 100%, RQD = 0%, FF = 0.33, RCT = 5 minutes, joints and fractures range 30° from assumed horizontal.

Run 5: 3:25-4:06 BASALT, highly vesicular, gray to red, very fine grained, slightly weathered, medium strong (R3). Discontinuities are closely spaced and in fair condition, CR = 100%, RQD = 0%, FF = 4.5, RCT = 41 minutes, joints and fractures ranges from 5° to 30° from assumed horizontal. Silts in seams starting at 42½ ft.

Run 6: 4:15-4:45 BASALT, highly vesicular, red to gray, very fine grained, slightly weathered, medium strong (R3). Discontinuities are closely spaced and in fair condition, CR = 90%, RQD = 43%, FF = 1.6, RCT = 30 minutes, joints and fractures ranges from 10° to 45° from assumed horizontal.

END OF CORING at 50.5 ft

Water at 10 ft 8 in with 11 1/2 ft of hollow-stem auger in the ground.

Boring then backfilled.

40.5 41.0

45.5

50.5

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 45° 20' 26.35" (45.340653°)

LONGITUDE (DEGREES): W -117° 4' 27.26" (-117.074238°)

D E

P T

H ft

Sheet 2 of 2

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 50.5'

LIQUID LIMIT

RQD (%)

AFTER DRILLING

Rock / Soil Core

Split Spoon

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

8" hollow-stem auger to 29.6'. HQ3 from 29.6' to 50.5'.

11+20, 10R

40.0

44.0

48.0

52.0

56.0

60.0

64.0

68.0

72.0

76.0

80.0

NOTES:

BORING BH16-01

COMPANY:

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: 3 /2

9/

SK Geotechnical LOGGER: Brandon Western

Cloudy

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Erik Hollibaugh

WEATHER:

PROJECT: OR WALLOWA 4602(1)

Automatic

WATER CONTENT (%)

10.7'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: Diedrich D120

D E

P T

H ft

10/26/2016

S A

M P

LE

R

10/26/2016

STATION, OFFSET:

PLASTIC LIMIT

14-12-15

10-11-11

10-13-3

8-7-6

2-4-6

18-29-43

30-50/5¾"

19-33-50/4½"

50-4¼"

30-50/2¾"

27-50/2"

50/¾"

Asphalt Concrete (0.2 ft thick) Clayey GRAVEL with sand, medium dense, brown, moist, fine to coarse, subangular to subrounded, homogeneous.

Fill.

Lean CLAY with gravel, stiff to very stiff, brown to gray, moist, low plasticity, homogeneous, fine to coarse angular clasts, red basalt clasts. Fill.

Lean CLAY with sand, firm to stiff, brown, moist, low plasticity, homogeneous, fine rounded clasts. Alluvium.

Poorly graded GRAVEL with silt, medium dense, brown, moist, fine to coarse, subrounded, homogeneous. Alluvium.

Poorly graded GRAVEL with silt and sand, very dense, brown, moist to wet, fine to coarse, rounded, homogeneous, with cobbles. Alluvium.

Silty GRAVEL with clay, sand, and cobbles, very dense, brown, moist to wet, fine to coarse, rounded to subrounded.

Alluvium.

Clayey GRAVEL with sand, very dense, brown, wet, fine to coarse, subrounded, homogeneous, with cobbles. Alluvium.

Difficult drilling. Switched to HQ3 coring at 30'.

Run 1: 2:40-3:50 Clayey GRAVEL with sand, very dense, brown, wet, fine- to coarse-grained, subrounded, homogeneous with cobbles and boulders. CR = 44%, RQD = 0%, RCT = 70 minutes.

After coring, advanced auger to 34.5'.

Run 2: 4:00-4:30 BASALT, dark gray, very fine grained, slightly weathered, medium strong to strong (R3-R4). Discontinuities are very closely spaced and in poor to fair condition, silt in fractures starting at 37 ft, CR = 100%, RQD = 24%, FF = 2.5, RCT = 30 minutes, joints and fractures ranges from 5° to 30° from assumed horizontal.

0.2

3.5

7.5

10.0

12.0

18.0

27.3

30.0

34.5

40.0

NP

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 45° 20' 26.14" (45.340594°)

LONGITUDE (DEGREES): W -117° 4' 26.58" (-117.07405°)

D E

P T

H ft

Sheet 1 of 3

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 74.6'

LIQUID LIMIT

RQD (%)

AFTER DRILLING

Rock / Soil Core

3" Shelby Tube

Split Spoon

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

8" hollow-stem auger to 30.0'. HQ3 from 30.0' to 74.6'.

11+70, 10L

0.0

4.0

8.0

12.0

16.0

20.0

24.0

28.0

32.0

36.0

40.0

NOTES:

BORING BH16-02

COMPANY:

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9/

SK Geotechnical LOGGER: Brandon Western

Cloudy

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Erik Hollibaugh

WEATHER:

PROJECT: OR WALLOWA 4602(1)

Automatic

WATER CONTENT (%)

13.5'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: Diedrich D120

D E

P T

H ft

10/27/2016

S A

M P

LE

R

10/28/2016

STATION, OFFSET:

PLASTIC LIMIT

Run 3: 7:50-8:12 BASALT, gray, very fine-grained, slightly weathered, medium strong to strong (R3-R4). Discontinuities are closely spaced and in poor to fair condition, CR = 100%, RQD = 43%, FF = 3, RCT = 22 minutes, joints and fractures ranges from 5° to 25° from assumed horizontal.

Run 4: 8:28-8:53 BASALT, gray, very fine grained, slightly weathered, strong (R4). Discontinuities are closely to moderately spaced and in poor to fair condition, CR = 100%, RQD = 67%, FF = 4, RCT = 25 minutes, joints and fractures ranges from 5° to 30° from assumed horizontal.

Run 5: 9:14-9:34 BASALT, slightly vesicular, red to dark gray, very fine grained, slightly to moderately weathered, medium strong (R3). Discontinuities are very closely spaced and in poor condition, interlaced with silt, CR = 100%, RQD = 24%, FF = 2.5, RCT = 18 minutes, joints and fractures ranges from 15° to 35° from assumed horizontal.

Run 6: 9:50-9:56 BASALT, slightly vesicular, red to dark gray, very fine grained, slightly to moderately weathered, medium strong (R3). Discontinuities are very closely spaced and in poor condition, interlaced with silt, CR = 100%, RQD = 0%, FF = 6, RCT = 6 minutes, joints and fractures 35° from assumed horizontal.

Run 7: 10:00-10:12 BASALT, slightly to moderately vesicular, red to dark gray, very fine grained, slightly weathered, medium strong (R3).

Discontinuities are closely spaced and in fair condition, interlaced with silt, CR = 100%, RQD = 83%, FF = 4, RCT = 12 minutes, joints and fractures ranges from 15° to 30° from assumed horizontal.

Run 8: 10:26-10:48 BASALT, moderately vesicular, red, very fine grained, fresh to slightly weathered, medium strong (R3). Discontinuities are closely to moderately spaced and in poor to fair condition, interlaced with silt, CR = 100%, RQD = 73%, FF = 1.4, RCT = 22 minutes, joints and fractures ranges from 5° to 45° from assumed horizontal.

Run 9: 11:05-11:24 BASALT, slightly vesicular, red to gray, very fine grained, slightly weathered, medium strong (R3). Discontinuities are closely to moderately spaced and in poor condition, CR = 100%, RQD = 51%, FF = 4, RCT = 19 minutes, joints and fractures ranges from 5° to 30° from assumed horizontal.

Run 10: 11:41-11:55 BASALT, slightly to moderately vesicular, red to brown, very fine grained, slightly weathered, medium strong (R3).

Discontinuities are closely to moderately spaced and in poor to fair condition, CR = 100%, RQD = 33%, FF = 5, RCT = 11 minutes, joints and fractures ranges from 5° to 90° from assumed horizontal.

Run 11: 12:09-12:31 BASALT, slightly vesicular, red to gray, very fine grained, slightly weathered, medium strong (R3). Discontinuities are closely spaced and in poor to fair condition, CR = 100%, RQD = 33%, FF = 3.5, RCT = 20 minutes, joints and fractures ranges from 5° to 60° from assumed horizontal.

END OF CORING at 74.6 ft

45.0

50.0

53.5 54.1

55.0

60.0

65.0

70.0

74.6

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 45° 20' 26.14" (45.340594°)

LONGITUDE (DEGREES): W -117° 4' 26.58" (-117.07405°)

D E

P T

H ft

Sheet 2 of 3

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 74.6'

LIQUID LIMIT

RQD (%)

AFTER DRILLING

Rock / Soil Core

3" Shelby Tube

Split Spoon

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

8" hollow-stem auger to 30.0'. HQ3 from 30.0' to 74.6'.

11+70, 10L

40.0

44.0

48.0

52.0

56.0

60.0

64.0

68.0

72.0

76.0

80.0

NOTES:

BORING BH16-02

COMPANY:

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: 3 /2

9/

SK Geotechnical LOGGER: Brandon Western

Cloudy

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Erik Hollibaugh

WEATHER:

PROJECT: OR WALLOWA 4602(1)

Automatic

WATER CONTENT (%)

13.5'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: Diedrich D120

D E

P T

H ft

10/27/2016

S A

M P

LE

R

10/28/2016

STATION, OFFSET:

Water at 13 1/2 ft with 11 1/2 ft of hollow-stem auger in the ground.

Boring then backfilled.

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 45° 20' 26.14" (45.340594°)

LONGITUDE (DEGREES): W -117° 4' 26.58" (-117.07405°)

D E

P T

H ft

Sheet 3 of 3

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 74.6'

LIQUID LIMIT

RQD (%)

AFTER DRILLING

Rock / Soil Core

3" Shelby Tube

Split Spoon

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

8" hollow-stem auger to 30.0'. HQ3 from 30.0' to 74.6'.

11+70, 10L

80.0

84.0

88.0

92.0

96.0

100.0

104.0

108.0

112.0

116.0

120.0

NOTES:

BORING BH16-02

COMPANY:

F ile

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9/

SK Geotechnical LOGGER: Brandon Western

Cloudy

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Erik Hollibaugh

WEATHER:

PROJECT: OR WALLOWA 4602(1)

Automatic

WATER CONTENT (%)

13.5'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: Diedrich D120

D E

P T

H ft

10/27/2016

S A

M P

LE

R

10/28/2016

STATION, OFFSET:

6-12-18

29-50/1½"

Asphalt Concrete (0.3 ft thick) Silty GRAVEL with sand, brown, moist, fine to coarse, angular, homogeneous. Base.

Well graded GRAVEL with clay and sand, medium dense to very dense, brown to red, moist, fine to coarse, angular, homogeneous. Fill.

(A-2-6) END OF BORING - Auger Refusal at 4.1 ft

Water not observed with 3 1/2 ft of solid-stem auger in the ground.

Boring then backfilled.

Base sample 3.5" - 5".

Subgrade sample 5" - 4.1'.

0.3 0.4

4.1

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 45° 20' 24.80" (45.340222°)

LONGITUDE (DEGREES): W -117° 4' 25.63" (-117.073787°)

D E

P T

H ft

Sheet 1 of 1

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 4.1'

LIQUID LIMIT

AFTER DRILLING

Split Spoon

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

12" solid stem auger.

13+00, 14L

0.0

4.0

8.0

12.0

16.0

20.0

24.0

28.0

32.0

36.0

40.0

NOTES:

BORING SG16-01

COMPANY:

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9/

SK Geotechnical LOGGER: Brandon Western

Cloudy

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Erik Hollibaugh

WEATHER:

PROJECT: OR WALLOWA 4602(1)

Automatic

WATER CONTENT (%)

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: Diedrich D120

D E

P T

H ft

10/29/2016

S A

M P

LE

R

10/29/2016

STATION, OFFSET:

4-5-5

2-1-6

Asphalt Concrete (0.2 ft thick) Silty GRAVEL with sand, loose, brown, moist, fine to coarse, angular, homogeneous. Fill.

Silty SAND, loose, brown, wet, fine, rounded, homogeneous. Fill.

END OF BORING

Water not observed with 4 ft of solid-stem auger in the ground.

Boring then backfilled.

Base sample NA.

Subgrade sample 1.5' - 3.5'.

0.2

4.0

5.5

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 45° 20' 7.06" (45.335294°)

LONGITUDE (DEGREES): W -117° 4' 39.72" (-117.077701°)

D E

P T

H ft

Sheet 1 of 1

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 5.5'

AFTER DRILLING

Split Spoon

AT COMPLETION

G R

A P

H

I…