GR_6-17_Nestucca_Final_Geotech_Report,_Oct2017.pdf

Nestucca River Back County Byway Phase 1 October 2017

Table of Contents 1-i

Geotechnical Report No. 6-17

Nestucca River Back County Byway Phase 1

FINAL GEOTECHNICAL REPORT

OR BLM SAL 040727(1)

U.S. Department of the Interior

Bureau of Land Management

Tillamook County, Oregon

October 2017

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Table of Contents i

TABLE OF CONTENTS

1 INTRODUCTION

1.1 Scope and Purpose

2 PROJECT DESCRIPTION

3 GEOLOGY

3.1 Geologic Hazards

3.2 Seismicity

4 SITE CONDITIONS

4.1 Average Temperatures and Precipitation

5 SUBSURFACE CONDITIONS

5.1 Laboratory Materials Testing

5.2 Soil and Rock Types

5.3 Groundwater

5.4 Landslides

6 ANALYSIS AND DESIGN RECOMMENDATIONS

6.1 MECHANICALLY STABILIZED EARTH WALLS

6.2 Special Rock Embankments

6.3 Soil Embankment Slopes

6.4 Cut Slopes

6.5 Landslide Repair

7 CONSTRUCTION CONSIDERATIONS

7.1 Excavation

7.2 Embankment

7.3 MSE Walls

7.4 Draped Mesh Landslide Area Mitigation

7.5 Aggregate Sources

8 LIMITATIONS

9 REFERENCES

List of Figures ii

LIST OF FIGURES

Figure 2-1 Project Location Map

Figure 2-2 Project Topographic Map

LIST OF TABLES

Table 3-1 Geologic Hazard Mapping Summary

Table 4-1 Climate Data Summary

Table 5-1 Groundwater Summary

Table 6-1 MSE Wall and SRE Design Summary

Table 6-2 Cut Slopes Design Summary

APPENDICES

APPENDIX A

Site Photographs

APPENDIX B

Site and Exploration Plans

APPENDIX C

Field Classifications for Soil and Rock

Unified Soil Classification System

Soil Descriptive Terminology

Rock Descriptive Terms

Boring Logs B16-01 to B16-13

Subgrade Boring Logs SG16-01 to SG16-06

Test Pit Logs TP16-01 to TP16-14

Rock Core Photos

Test Pit Photos

APPENDIX D

Laboratory Test Reports

APPENDIX E

Landslide Trip Reports

Introduction 1

1 INTRODUCTION

This report provides geotechnical investigation results, analysis, design and construction recommendations for Phase 1 of the Nestucca River Back Country Byway project. This project was performed for the Salem District of the U.S. Department of the Interior Bureau of Land

Management (BLM). The project stationing referenced in this report is from the 100% Design

Set, dated July 2017.

The following reports were provided by BLM for our use at the start of project:

• Draft Engineering Geologic Report Nestucca River National Back County Byway Road

Widening and Paving, dated September 8, 2014, by LEI Engineering and Surveying

• Nestucca Transportation Study, dated July 10, 2015, by DKS Associates

1.1 SCOPE AND PURPOSE

The geotechnical scope of work for this project included review of the above-referenced reports, a visual reconnaissance along the proposed alignment, and a subsurface exploration program consisting of 13 geotechnical test borings, 14 test pits, and 6 subgrade sample borings. Other geotechnical work included a several site visits to observe cleanup and progression of a reported landslide near mainline station 783+90. The geotechnical borings, test pits, and laboratory tests were completed by Western Federal Lands Highway Division (WFLHD) and our subcontractors.

This report was prepared to provide geotechnical recommendations for cut slope angle and construction methods, fill slope angles and materials, and retaining wall engineering, design, and construction considerations. Rockfall mitigation recommendations for the slide area are also discussed.

The current project does not include replacement of Elk Creek Bridge. However, borings for the bridge foundation were performed as part of this subsurface investigation and will be included in this memorandum as part of the subsurface information. It is our understanding that the bridge may be developed to a Type, Size, and Location (TS&L) level of effort for future use, including a

Preliminary Foundation Memo under separate cover.

The following reports were previously prepared by WFLHD:

• Nestucca River Back Country Byway, OR BLM SAL 040727(1), Preliminary

Geotechnical Recommendations, Geotechnical Memo GM15-16, dated May 2, 2016

• Preliminary Bridge Foundation Recommendations, Elk Creek Bridge Replacement, Nestucca River Back Country Byway Road Network, OR BLM SAL 040727(1), Geotechnical Memorandum GM1-17, dated June 23, 2017

This report supersedes all other previous reports for this project.

2 Project Description

2 PROJECT DESCRIPTION

The project is located approximately 23 miles west of Carlton, Oregon on the Nestucca River

Access Road in Tillamook County, Oregon as shown in Figure 2-1 Project Location Map. The project consists of an approximately 2.7-mile stretch of gravel road between mainline stations

668+50 to 810+60 that will be widened and paved. The project starts on the east end at station

668+50 near Davidson Pit and ends at station 810+60 near Elk Creek Bridge.

Widening the roadway prism will involve a combination of slope cuts and earth embankments, rock fill embankment, and retaining wall structures. Numerous culverts will be replaced, including two relatively large Aquatic Organism Passage (AOP) culverts. Backfill for the deeper culverts will require special rock embankment fill to match the steep adjacent slopes.

Improvements to Elk Bend Campground are also included in the project. These improvements include expansion and paving of the parking area, which will require the construction of

Mechanically Stabilized Earth retaining structures. A trail will also be constructed to wind down the hillside from the new parking area to the campground level below.

A moderate-sized but relatively shallow landslide occurred during project development near station 783+90 starting in March 2016. As of the writing of this report, the slide is still active, but a separate BLM contract was issued to scale the slide area for temporary stabilization until rockfall netting and long-term erosion control measures can be installed as part of the mainline construction project.

Project Description 3

Figure 2-1 Project Location Map

Figure 2-2 Project Topographic Map

4 Geology

3 GEOLOGY

The project is located in the Coast Range geologic province of Oregon. According to the

Preliminary Geologic Map of the West Half of the Vancouver (Wa.-Ore.) 1 Degree x 2 Degree

Quadrangle, Oregon - 19831, the site is mapped as “Tsr” on the approximate east half of the project, and “Ti” on the approximate western half of the project.

The “Tsr” unit is defined as Siletz River Volcanics (Lower and Middle Eocene) described as pillow flows, tuff-breccias, massive flows and sills of tholeiitic and alkalic basalt; unit pervasively zeolitized and veined with calcite; upper part of the sequence contain numerous interbeds of basaltic siltstone, sandstone, and locally derived basalt conglomerate, thick beds of basaltic tuff, and rare fossiliferous, calcareous-rich beds. The age range is reported to be on the order of

51.7 to 56 million years old.

The “Ti” unit is defined as Tertiary Intrusive Rocks (Eocene to Miocene) described as primarily sills and dikes of aphanitic to coarse-grained, aphyric to augite and plagioclase-phyric basalt;

includes intrusions in the upper part of the Siletz River Volcanics of middle to late Eocene age and intrusion of late Eocene, Oligocene and middle Micoene age, mostly in the marine sedimentary sequence.

3.1 GEOLOGIC HAZARDS

The Oregon HazVu: Statewide Geohazards Viewer2 website was used to screen the project vicinity for geologic hazards, as well as the USGS Interactive Fault Map3. HazVu maps the following geologic hazards:

1 Wells, R.E., Niem, A.R., MacLeod, N.S., Snavely, P.D., and Niem, W.A., 1983, Preliminary geologic map of the west half of the Vancouver (Wa.-Ore.) 1 degree X 2 degree quadrangle, Oregon: U.S.

Geological Survey, Open-File Report OF-83-591, scale 1:250,000.

2 http://www.oregongeology.org/hazvu/, accessed 4/14/2016.

3 http://earthquake.usgs.gov/hazards/qfaults/map/, accessed 4/14/2016.

http://www.oregongeology.org/hazvu/ http://earthquake.usgs.gov/hazards/qfaults/map/

Geology 5

Table 3-1 Geologic Hazard Mapping Summary

Geologic Hazard Mapping Description

Active Faults Nearest active fault is the

Tillamook Bay fault zone approx.

10 miles north

Based on the distance to the site, the risk of surface rupture is considered low

Liquefaction No mapping of areas that appear to be affecting the roadway in the project area

The risk is considered low based on the mapping.

Expected Earthquake

Shaking

“Very strong” mapping over the entire vicinity

Very strong ground motions expected - unavoidable

Landslide Hazard “High” mapping over the entire vicinity

Landsliding is likely

Volcanic Hazard No areas mapped as high or moderate in the region

Risk is considered low

The HazVu landslide inventory does not maps any landslides within the project corridor, except for a landslide across the river near the confluence with Elk Creek. Since the landslide is across the river, this area should not affect the roadway design.

3.2 SEISMICITY

The seismicity of the project area was considered for the retaining wall design; however, the scaled peak ground acceleration, As, for an earthquake with a return period of approximately

1,000 years was determined to be 0.366g using the USGS Seismic Design Maps website4.

Seismic design for retaining walls is not required by AASHTO (2014) where the As is less than

0.4g. Therefore, additional seismic loads were not considered in the design of the retaining structures and slopes.

It should be noted that landslides and displacements of retaining structures could occur during strong ground shaking from an earthquake, but it is not practical to mitigate the earthquake loads for these structures due to the relatively high cost, especially for a low volume road. If it is determined that seismic loads on slopes or retaining structures should be considered for this project, the WFL Geotechnical group should be contacted for additional recommendations.

4 http://earthquake.usgs.gov/designmaps/us/application.php, accessed 4/14/2016.

http://earthquake.usgs.gov/designmaps/us/application.php

6 Site Conditions

4 SITE CONDITIONS

The Nestucca River Access Road runs east-west on the north side of Nestucca River through relatively steep terrain in the Oregon Coastal Range. The slopes generally face south, southwest, and southeast down towards the river and range from relatively gentle soil slopes to near vertical rock cuts.

The slopes are typically moderately wooded with a mixture of deciduous and evergreen trees.

We understand from the Biological Assessment (BLM, 2016) that the trees are mostly red alder with some big leaf maple and conifers. The larger diameter Douglass Fir trees may contain red tree voles, which constrain the widening route due to the desire to protect the red tree vole habitat.

4.1 AVERAGE TEMPERATURES AND PRECIPITATION

The project site is in a wet and rainy climate with precipitation expected throughout the year.

Table 4-1 shows the average maximum and minimum temperatures, average monthly precipitation, and average monthly snowfall data for the period from 2006 to 2016 for the

Tillamook 6SE, Oregon (358498) weather station (Western Region Climate Center, 2017).

Table 4-1 Climate Data Summary

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

Avg. Max.

Temp. (F)

48.5 50.2 51.8 54.4 59.0 62.7 67.8 68.5 67.4 59.7 52.4 46.7 57.4

Avg. Min.

Temp. (F)

37.5 37.6 37.6 38.8 42.3 47.2 50.2 50.9 48.0 43.6 40.1 35.8 42.5

Avg. Total

Precip. (in.)

13.3 8.6 11.1 7.7 4.4 3.6 1.2 1.9 2.6 6.3 12.5 11.6 84.9

Avg. Total

Snowfall

(in.)

0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Avg. Snow

Depth (in.)

0 0 0 0 0 0 0 0 0 0 0 0 0

Note:

1) Period of Record : 08/01/2006 to 04/30/2016.

Subsurface Conditions 7

5 SUBSURFACE CONDITIONS

The approximate locations of the explorations are included on the Site and Exploration Plans in

Appendix A. The boring logs, test pits logs, and subgrade sample logs are included in Appendix

B. The explorations were performed from January 13 to 28, 2016.

The geotechnical test borings, B16-01 to B16-13, were performed for three primary structures:

1) AOP culvert replacements; 2) fill side retaining structures; and, 3) bridge foundations at Elk

Creek. The AOP culvert borings and bridge foundation borings were performed in the existing roadway with a truck-mounted CME-75 drill rig. The fill side borings were performed on the downhill slope using a skid-mounted Diedrich D-25 drill rig placed on a drilling platform with the assistance of a crane.

To evaluate the cut slope conditions and excavation potential in bedrock, test pits were performed on the cut side of the road using a 200-series excavator (Linkbelt 2800) with a 2-foot wide bucket with rock teeth. Photos of the test pits are included in Appendix C.

5.1 LABORATORY MATERIALS TESTING

Selected split-barrel (SPT) soil samples and intact Shelby tube samples were submitted to the

WFLHD Materials Laboratory for soil index testing and direct shear testing. Laboratory test reports are contained in Appendix D.

The following is a list of tests that were completed on the selected soil and rock samples and the standards that were followed:

• Particle Size Analysis – AASHTO T 88

• Liquid Limit, Plastic Limit, and Plasticity Index – AASHTO T 89/90

• Apparent Specific Gravity – AASHTO T 100

• Direct Shear – AASHTO T 236

• Natural moisture – AASHTO T 265

• Organic Content – AASHTO T 267

• Rock Unconfined Compressive Strength

The results of the soil index tests were used to classify the samples according the Unified Soil

Classification System (USCS). The USCS classification of individual laboratory tested soil samples is reported on the boring logs.

5.2 SOIL AND ROCK TYPES

The native subsurface materials appear to general consist of alluvium, colluvium, and possibly residual soils over a mix of bedrock types. The alluvial soils include loose to medium sandy silts to clayey silts, silty sands, and very soft silts with organics at the AOP culvert crossings and ravines. Colluvium or possibly breccia was observed in a recent slide area, which will be

8 Subsurface Conditions discussed in further detail. The clayey sand to silty sand soils observed in some of the test pits may be residual soils from complete weathering of bedrock.

The bedrock types encountered included mostly basalt breccia, flow basalt, and basalt boulders.

Limited material, interpreted to be volcanic sandstone, was also encountered in TP16-01 near the eastern end of the project. The breccia bedrock consisted of basalt boulders and cobbles in a sandy matrix. The sandy matrix can be weak and friable near the weathered surface but becomes increasingly strong and less weathered with depth from the cut surface. The basalt bedrock varied between very strong boulders in a silty sand matrix to weathered formations of massive weak to medium strong flow basalt. The bedrock quantity and quality varies highly along the alignment, especially at the western end of the site. In TP16-14, the basaltic boulders exhibited a spheroidal weathering pattern, where 1/8- to ¼-inch thick layers were observed to peel off like layers of an onion.

The borings performed on the side slopes encountered what we interpret to be sidecast fill materials. The fill consisted of re-graded native silty sand, clayey sand, silt, and gravel soils mixed with cobbles and boulders. The fill was generally in a very loose to loose condition and generally wet of optimum moisture content.

It should be noted that the basalt cores appear to be clay-rich. This high clay content has been known locally to produce poor quality aggregates due to the expansion and breakdown of the aggregate once crushed and wetted (Lofgren, 2017).

5.3 GROUNDWATER

Groundwater was encountered in several of the explorations. Table 5-1 below summarizes the groundwater depths encountered at the time of drilling or excavating.

Subsurface Conditions 9

Table 5-1 Groundwater Summary

Exploration GW Depth (ft) GW Elevation (ft)1

B16-01 11.5 1132±

B16-02 12 1131.5±

B16-03 NE -

B16-04 24 1162±

B16-05 10 1029±

B16-06 9.5 1029.5±

B16-07 NE -

B16-08 NK -

B16-09 NK -

B16-10 NK -

B16-11 NK -

B16-12 11.5 913.5±

B16-13 14.5 911.5±

TP16-01 NE -

TP16-02 NE -

TP16-03 NE -

TP16-04 NE -

TP16-05 NE -

TP16-06 NE -

TP16-07 NE -

TP16-08 NE -

TP16-09 NE -

TP16-10 3, 10 991, 984±

TP16-11 10 977±

TP16-12 NE -

TP16-13 NE -

TP16-14 NE -

Notes: NE = Not Encountered

NK = Not Known due to use of water while drilling 1 Estimated elevations from the topographic plan. Not surveyed elevations.

5.4 LANDSLIDES

A landslide was reported by BLM to have occurred on March 24, 2016 and again on March 28, 2016. The slide occurred approximately 0.2 mile east of the Elk Bend Campground near station

783+90. The slide appears to have been a relatively thin “skin” slide consisting of loose surficial boulders, sandy soils, and vegetation. Prior to the slide the materials in this area appeared similar to the breccia found exposed along other portions of the corridor, although after being

10 Subsurface Conditions exposed by the slide it appears darker in color, looser, and less cemented. After the area was exposed to rain, the lower portion of the slope was observed to be an intact but fractured basaltic bedrock. This area is likely weathered colluvium over the bedrock and has been relatively stable for a long time based on the diameters of the very large trees above the slope area. Additional information is provided in the Trip Reports included as Appendix C. This slide area has since been scaled for temporary stability under contract to the BLM in August 2017, in anticipation of draped mesh being installed as part of the mainline widening construction project.

Two other landslides were reported by LEI Engineering and Surveying in their Draft Engineering

Geology Report, dated September 8, 2014, included in Appendix E. One landslide was mapped in LEI’s Segment 14, which we estimate to be in the vicinity of stations 733+00 to 734+00. We were not able to identify landslide features or materials in this area during our visual reconnaissance. Furthermore, we did not perform explorations in this area since no cuts were planned in this section. The other landslide was mapped in LEI’s Segment 22, which we estimate to be near station 802+00. We were able to visually identify this slide to be a minor slump above the road. No explorations were performed in this area, since no cuts are planned.

Analysis and Design Recommendations 11

6 ANALYSIS AND DESIGN RECOMMENDATIONS

The above information was analyzed to determine design recommendations for reinforced soil slopes, rock fill slopes, and cut slopes. In general, we agree largely with the preliminary slope recommendations provided by LEI for development of the road alignment and cross-sections.

However, we recommend more retaining structures and a few flatter cut slope areas, based on the results of the explorations.

Reinforced soils slopes (RSS) were originally planned for support of the fill side (downhill) road widening, due to their ability to be planted and the reduced visual impact it would have within the scenic byway setting. However, due to the very steep embankment and natural slopes, the

RSS catch points extended downslope significantly resulting in high RSS heights. Therefore, more vertical Mechanically Stabilized Earth (MSE) walls were designed to reduce the wall heights. The MSE walls will have a bench in front of them that will be planted to screen the walls and reduce the visual impact on the scenic byway.

The following sections provide our recommendations for roadway design.

6.1 MECHANICALLY STABILIZED EARTH WALLS

MSE walls for this project will utilize typical welded wire fabric (WWF) facing elements with 18-inch vertical lifts. The WWF facing elements will have a gabion rock backfill with no hardware cloth or geogrid allowed at the face. Black wire (non-galvanized) will be acceptable. If galvanized wire is used, it must be treated with a weathering agent to reduce the brightness of the galvanization for reduced visual impact. Long-term stability of the black steel face will be mitigated by the internal wrap of the geogrid reinforcement. We understand that the plantings will be performed by the Forest Service’s revegetation team.

The design software MSEW 3.0 by ADAMA Engineering, Inc. was used with the AASHTO LRFD

Bridge Design Specifications analysis method for external, internal, and global stability analysis of the MSE walls as wrapped face geogrid walls. Each current MSE wall location was analyzed for the estimated grid length that would satisfy global stability of the retaining structure over the steep slope areas. A summary of the proposed MSE wall locations and maximum grid lengths are shown in Table 6-1 below.

6.2 SPECIAL ROCK EMBANKMENTS

Fill areas where a 1V:1.25H Special Rock Embankment (SRE) can be constructed are also recommended, although fills at these steep slope angles require the use of coarse angular rip-rap rock. These SRE slopes are typically bare due to their steepness. Over time, natural organic material will infill the rock voids and some vegetation may become established. The rock should follow the specifications for Special Rock Embankment in FP-14. A summary of the proposed

SRE slope locations is shown in Table 6-1 below.

12 Analysis and Design Recommendations

6.3 SOIL EMBANKMENT SLOPES

All other areas are considered soil embankment areas and should be generally limited to maximum slopes of 1V:1.5H for limited heights of less than approximately 10 to 15 feet. These slopes should be designed for both temporary and permanent erosion control, such as the use of a hydromulch with tackifier and native grass seed meeting BLM mix requirements.

Table 6-1 MSE Wall and SRE Design Summary

Station

Start

Station

End

Boring

No.

Recommended

Structure

Approx.

Length

(ft)

Approx.

Max.

Height

(ft)

Existing

Slope

Angle

(deg.)

Max.

Grid

Length

(ft)

668+50 668+70 - 1:1.25 SRE 20 4 - -

671+40 671+72 B16-02 1:1.25 SRE 32 16 - -

678+25 678+50 - 1:1.25 SRE 25 8 - -

680+85 681+60 - 1:1.25 SRE 75 8 38 -

691+70 692+05 - 1:1.25 SRE 35 4 35 -

699+60 699+85 - 1:1.25 SRE 25 7 - -

706+10 706+20 B16-03 1:1.25 SRE 10 8 35 -

706+20 708+90 B16-03 MSE Wall 270 9 35 10

711+65 712+10 - 1:1.25 SRE 45 7 35 -

718+25 719+25 B16-04 1:1.25 SRE 100 35 36 -

736+00 736+30 - 1:1.25 SRE 30 3 38 -

739+65 740+15 - 1:1.25 SRE 50 10 34 -

742+80 743+45 - 1:1.25 SRE 65 6 27 -

771+80 772+40 - 1:1.25 SRE 60 4 32 -

773+90 774+50 - 1:1.25 SRE 60 15 40 -

776+90 779+15 B16-07 MSE Wall 225 10 42 16

779+85 781+20 - MSE Wall 135 8 40 10

782+55 788+75 B16-08, B16-09

MSE Wall 620 11 43 12

Analysis and Design Recommendations 13

Station

Start

Station

End

Boring

No.

Recommended

Structure

Approx.

Length

(ft)

Approx.

Max.

Height

(ft)

Existing

Slope

Angle

(deg.)

Max.

Grid

Length

(ft)

789+50 790+00 B16-10 1:1.25 SRE 50 10 46 -

793+87 795+25 - MSE Wall 138 15 - 12

803+40 804+60 B16-11 MSE Wall 120 12 42 13

6.4 CUT SLOPES

Significant cut slope areas were evaluated with test pits for both stability and excavatability. Cut slope analyses are based on a combination of reported good performance of existing stable cut slopes, observed recent slide area conditions, habitat trees above certain slope areas, and cost versus risk considering the low traffic volume of the roadway. The following table provides our cut slope recommendations, although the slopes may vary locally to fit the road geometry to the lay of the land in especially in transition zones.

Table 6-2 Cut Slopes Design Summary

Design

Stations

Recommended

Cut Slope

Anticipated Soil/Rock

Conditions Comments

667+00 to

674+25

1V:1.5H Soil over sandstone

674+25 to

685+25

1V:1H Soil over sandstone Ideally, soil would be

1V:1.5H but the backslope is very steep.

685+25 to

705+00

2V:1H Breccia

705+00 to

706+25

1V:1H Soil? No test pit performed since no significant cuts planned here.

706+25 to

715+00

2V:1H Breccia

715+00 to

716+50

1V:1.5H Soil over breccia

716+50 to

717+50

2V:1H Breccia Basalt flow caps breccia upslope

14 Analysis and Design Recommendations

Design

Stations

Recommended

Cut Slope

Anticipated Soil/Rock

Conditions Comments

717+50 to

726+50

1V:1.5H to

1V:2H

Soil 1.5H:1V cut up to 10 ft cut height, 2H:1V cut for height

>10 ft

726+50 to

738+50

2V:1H Breccia and basalt Avoid cuts in LEI mapped landslide from approximately 733+00 to

734+00.

738+50 to

777+00

1V:1.5H to

1V:2H

Soil 1.5H:1V cut up to 10 ft cut height, 2H:1V cut for height

>10 ft

777+00 to

789+25

2V:1H Breccia and basalt Avoid or minimize cuts in recent slide and suspect old slide area from approx.

782+00 to 787+00.

789+25 to

803+00

1V:1.5H Soil

803+00 to

809+25

1V:1H Highly variable soil and weathered basalt boulders

6.5 LANDSLIDE REPAIR

As discussed in the attached landslide trip reports, the boulders exposed in the steep slope area may continue to ravel and fall into the road. For a permanent condition, we recommend that the upper slope consisting of soils and loose rock be cut back to a more stable angle on the order of

1:1 and stabilized with a heavy-duty erosion control fabric covered with draped mesh. The current design does not include a slope cut in this area, but some additional scaling or grading may be necessary prior to installing the anchors for the draped mesh and promote better contact between the mesh and the soil/rock. It should be noted that the purpose of the draped mesh is to control falling rocks by reducing bounce and allowing them to be deposited in the ditch for removal by maintenance crews. The draped mesh does not pin the rocks in place and prevent them from falling. A fully pinned mesh system was evaluated, but is cost prohibitive for this project given the low volume of the road.

Several of the very large trees at the top of the slope may need to be removed, which may be restricted by habitat concerns of these trees. If the slope cannot be cut back, the jersey barriers or other type of rockfall catchment system should be implemented as part of the permanent design. BLM maintenance crews should also be consulted on the preferred method of maintenance in this area, which will help determine the design of the rockfall mitigation structure.

Construction Considerations 15

7 CONSTRUCTION CONSIDERATIONS

7.1 EXCAVATION

We understand that the original road construction in the 1970’s used rock blasting. However, blasting will not be allowed now for environmental protection reasons. In general, the slightly to moderately weathered cuts from the original road construction may be able to be excavated a few feet with heavy equipment, although hydraulic breakers or other rock splitting methods will likely be needed for higher and deeper cuts and in fresher rock areas. The contractor should be responsible for walking the site and determining the best means and methods for performing the soil and rock cuts based on the constraints of the project. Some rock cuts will likely be too narrow to use a bulldozer with a ripping shank, and time intensive hydraulic hammering will likely be necessary.

Soil slopes appear to be relatively excavatable based on the test pits. Seepages may be encountered any time of the year in this relatively wet part of Western Oregon, and may require buttressing with riprap and filter fabric where encountered.

Temporary slope angles and/or the need for shoring for excavation of the MSE wall foundations should be the responsibility of the contractor based on the conditions encountered, traffic/equipment loading above the temporary cut, and other factors under their control during construction. Where competent bedrock is encountered within the planned geogrid extents, the

WFLHD geotechnical engineer should be contacted for evaluation of the conditions and potential truncation of the geogrid reinforced zone.

7.2 EMBANKMENT

Roadway embankment will likely be constructed with cut materials consisting of rock and mixture of sand, silt/clay, and gravel. Embankments constructed with silt/clay matrix material excavated on site should be constructed no steeper than 1V:2H. Care should be taken when mixing rock with soil, since open-graded rock placed against soil can allow the finer material to migrate into the voids of the rock resulting is settling or loss of ground in extreme cases.

Geotextile filter or separator fabrics or well-graded materials should be used to filter the finer materials and keep them separated.

Although coarse rock can be useful for a bridging or stabilization layer over soft subgrades, the rock should be limited in deeper fill areas, where the lower strength fine grain materials can typically be embanked and capped with coarser materials for better pavement performance.

Coarse materials must also be capped with a sufficient thickness of road base aggregate to prevent hard points under the pavements. The WFLHD Materials Engineer should be contacted for assistance with construction options if pavement subgrades differ from those assumed during design or specified for pavement support.

Due to the likelihood that the cut rock materials will have a high clay fraction and breakdown over time, the use of cut rock for fill slopes should not be planned for rip rap or SREs and should be limited to 1V:1.5H unless the material is tested with DMSO (see Section 7.5 of this report).

16 Construction Considerations

7.3 MSE WALLS

MSE walls on this project were designed by the WFLHD geotechnical and design team due to the steep terrain and as a crucial part of the designed alignment on some very tight areas.

However, to allow for open competition and cost-effective bid options contractor-design alternatives at no cost to the government may be considered that meet the intent, aesthetic, stability, and specifications of the design in the plans.

The subsurface drainage system consists of partial coverage of the cut slope with a geocomposite sheet drain. This partial coverage is intended to reduce hydrostatic pressure should incidental groundwater be encountered after construction. If areas of active seepage are encountered or identified during construction, these seepage areas should be modified to include 100 percent coverage with the geocomposite sheet drains. This additional coverage will allow direct hydraulic connection with the perforated pipe system to route the water away from the wall backfill and foundation.

A member of the Geotechnical Team should be present to observe foundation conditions of the

MSE walls to confirm that the subsurface conditions are consistent with the materials encountered in the subsurface exploration and assumed during design.

7.4 DRAPED MESH LANDSLIDE AREA MITIGATION

The recent landslide area near station 783+90 to 784+90 was temporarily scaled in August

2017. An erosion control hydromulch and seed mix should have been placed over the area at the end of summer closer to when the rainy season will begin to provide some water for grass growth. These temporary stabilization measures may or may not endure the very wet rainy season that the project area experiences on the west side of the Coast Range. Therefore, changes in the conditions of the rock and soil overburden should be expected.

The plans call for anchoring of the draped steel mesh at the top of the exposed area, after some additional scaling is performed to remove tree stumps, root overhangs, loose boulders, and loose soil wedges on the slope. The slope area is very high and difficult to access. A pioneer road may not be feasible or allowed due to the numerous vole habitat trees that would be removed by such a route. Therefore, a large crane may be needed to load heavy equipment to the upper slope, or work must be done with hand tools.

Anchors will likely encounter boulders, cobbles, gravel and other materials floating in the soil matrix of the colluvium overburden. Competent rock may be deeper than can be reached by typical draped mesh anchors. Therefore, the contractor should expect to use anchors with soil adhesion properties. No geotechnical explorations were performed at the top of the slope.

To reduce the visual impact of the draped mesh, the galvanized mesh, cables, and mounting hardware should be treated with a weathering agent to reduce brightness of the materials and blend in better with the surrounding landscape.

Construction Considerations 17

7.5 AGGREGATE SOURCES

As discussed in the Subsurface Conditions section, the basalt in the site vicinity is known from past WFLHD experience to be clay-rich and prone to premature degradation once crushed and wetted. All aggregate sources (including pavement materials, base aggregate, rip rap, and special rock embankment) for the project should be tested for durability using the standard

WFLHD Method of Test for Accelerated Weathering of Aggregate by Use of Dimethyl Sulfoxide

(DMSO), available upon request.

18 Limitations

8 LIMITATIONS

This report was prepared to provide subsurface investigation results and geotechnical recommendations for road widening along the Nestucca River Access Road in Tillamook

County, Oregon. 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 between borings. The observed water levels and/or conditions indicated on the boring and test pit logs are as recorded at the time of the exploration. The water levels and/or conditions may vary considerably, with time, according to the 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, during construction, soil conditions are encountered that vary from those discussed in this report or historical reports, 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 Eric Lim, WFLHD Geotechnical

Engineer, at (360) 619-7826, or eric.lim@dot.gov.

mailto:eric.lim@dot.gov

Limitations 19

GEOTECHNICAL REPORT NO. 6-17

FINAL GEOTECHNICAL REPORT

Nestucca River Back Country Byway Phase 1

OR BLM SAL 040727(1)

Tillamook County, Oregon

October 2017

Prepared and Reviewed by: _________________________________________

Eric Lim, PE, Geotechnical Engineer

20 References

9 REFERENCES

American Association of State Highway and Transportation Officials (2014), AASHTO LRFD

Bridge Design Specifications, 7th Edition, Washington, D.C.

BLM – Bureau of Land Management (2016), Biological Assessment for the Nestucca Back

Country Byway Project

Kavazanjian, and others (2011), LRFD Seismic Analysis and Design of Transportation

Geotechnical Features and Structural Foundations, GEC No. 3, FHWA-NHI-032.

Lofgren, David (2017), personal communication regarding aggregate deterioration along the

Nestucca River Access Road during the 1990s, January 17, 2017

Oregon Department of Geology and Mineral Industries (DOGAMI), Oregon HazVu: Statewide

Geohazards Viewer website, http://www.oregongeology.org/hazvu/, accessed 4/14/2016.

Wells, R.E., Niem, A.R., MacLeod, N.S., Snavely, P.D., and Niem, W.A., 1983, Preliminary geologic map of the west half of the Vancouver (Wa.-Ore.) 1 degree X 2 degree quadrangle, Oregon: U.S. Geological Survey, Open-File Report OF-83-591, scale 1:250,000.

Western Regional Climate Center (2015), Cooperative Climatological Data Summaries, Tillamook 6SE, OR (358498): www.wrcc.dri.edu, accessed October 2, 2017 http://www.oregongeology.org/hazvu/ http://www.wrcc.dri.edu/

APPENDIX A

Site Photographs

Photo A-2, Close up of subgrade boring SG16-05.

Photo A-1, Subgrade boring SG16-05.

Photo A-4, Boring B16-04 location facing south.

Photo A-3, Boring B16-04 location facing northwest.

Photo A-6, Boring B16-07 location facing east.

Photo A-5, Boring B16-07 location facing southwest.

Photo A-8, Boring B16-09 location facing west.

Photo A-7, Boring B16-09 location facing east.

Photo A-10, Boring B16-11 location facing northeast.

Photo A-9, Boring B16-10 location facing east.

APPENDIX B

Site and Exploration Plans

11401140

1145 11

11401140

IR

I R

I R

N

CP

15061

CP

BLM1

CP

CP

CP

CP

CP

LEGEND:

Approx. Test Pit location and number and number

Approx, Subgrade Boring location

Approx. Boring location and number

STATE PROJECT

NUMBER

SHEET

I n t_ ft

D c m y fi le s p w p r o d u c ti o n d o r b s a l4 d b .d g n

OR BLM SAL 040727(1)

A

M

J u n e

C h e c k e d b y

D e s ig n e d b y

N

E=84354.32

N=37155.26

CP

15064

CP

CP

15066

CP

B16-02

B16-01

SG16-01

TP16-01

TP16-02

SHEET 1 of 6

PLANS

SITE AND EXPLORATION

BEGIN PROJECT

M

ATCH

LIN

E A

668+50.00

Country Byway Phase 1

Nestucca River Back

OR BLM SAL 040727(1)

M A

T C

H L I N

E

MATCHLINE B

STATE PROJECT

NUMBER

SHEET

I n t_ ft m y fi le s p w p r o d u c ti o n d o r b s a l4 d c .d g n

OR BLM SAL 040727(1)

u n e

C h e c k e d b y

D e s ig n e d b y

N

N

SG16-02

TP16-03

TP16-04

B16-03

TP16-05

TP16-06

CP

CP

15069

CP

CP

CP

CP

15073 CP

CP

P

10008

PP

10009

10017

SHEET 2 of 6

PLANS

SITE AND EXPLORATION

M A

T C

H L

IN

E C

M A

T C

H L I N

E C

M A

T C

H L I N

E B

MATCHLINE D

11451145

STATE PROJECT

NUMBER

SHEET

I n t_ ft m y fi le s p w p r o d u c ti o n d o r b s a l4 d d .d g n

OR BLM SAL 040727(1)

u n e

C h e c k e d b y

D e s ig n e d b y

N

N

TP16-07

TP16-08

B16-04

SG16-03

CP

CP

CP

CP

CP

CP

SHEET 3 of 6

PLANS

SITE AND EXPLORATION

MATCHLINE E

M A T C

H L

IN

E D

M A T C

H L

IN

E E

M A

T C

H L I N

E F

10351035

D

R

EI

T- E

R V

O D

STATE PROJECT

NUMBER

SHEET

I n t_ ft m y fi le s p w p r o d u c ti o n d o r b s a l4 d e .d g n

OR BLM SAL 040727(1)

u n e

C h e c k e d b y

D e s ig n e d b y

N

N

CP

15082

CP

CP

CP

CP

15086

CP

CP

B16-05

B16-06

SG16-04

SHEET 4 of 6

PLANS

SITE AND EXPLORATION

M A

T C

H L I N

E F

M A T C H

LI

N E G

M A

T C

H L I N

E H

M A T C

H L

IN

G

970 975

990990

10051005

10101010

98098

990 990

MP

STATE PROJECT

NUMBER

SHEET

I n t_ ft m y fi le s p w p r o d u c ti o n d o r b s a l4 d f.

d g n

OR BLM SAL 040727(1)

u n e

C h e c k e d b y

D e s ig n e d b y

N

N

SG16-06

B16-11

TP16-12

B16-10

TP16-10

TP16-11

B16-07

SG16-05

B16-08

B16-09

TP16-09

CP

CP

CP

CP

15092 CP

CP

CP

15095

CP

15096

CP

15097

SHEET 5 of 6

PLANS

SITE AND EXPLORATION

M A

T C

H L

IN

E H

M A

T C

H L I N

E I

M

ATCH

LIN

E J

M A

T C

H L I N

I

E L

K C

R E E

K R

D

STATE PROJECT

NUMBER

SHEET

I n t_ ft m y fi le s p w p r o d u c ti o n d o r b s a l4 d g .d g n

OR BLM SAL 040727(1)

u n e

C h e c k e d b y

D e s ig n e d b y

N

TP16-13

TP16-14

B16-12 B16-13

CP

CP

CP

CP

10003

10001

15099

SHEET 6 of 6

PLANS

SITE AND EXPLORATION

M A

T C

H L

IN

E J

815+55.00

Country Byway Phase 1

Nestucca River Back

OR BLM SAL 040727(1)

END PROJECT

E=80839.60

N=35480.00

APPENDIX C

Field Classifications for Soil and Rock Unified Soil Classification System

Soil Descriptive Terminology Rock Descriptive Terms

Boring Logs B16-01 to B16-13 Subgrade Boring Logs SG16-01 to SG16-06

Test Pit Logs TP16-01 to TP16-14 Rock Core Photos

Test Pit Photos

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)

8 7 7 (14" = 78%)

2 2 3 (14" = 78%)

1 1 3 (12" = 67%)

2 3 2 (12" = 67%)

1 3 16 (10" = 56%)

50/3" (3" = 100%)

6 50/5" (10" = 91%)

S-1

S-2

S-3

S-4

S-5

S-6

S-7

Gravel surfacing

Silty SAND with gravel, medium dense, orange-brown, moist (Fill) less gravel rough drilling at 12 feet sample becomes wet

BRECCIA, recovered as silty SAND with gravel, very dense, dark brown with white specks of zeolite, moist slow drilling, basalt chips recovered, probable boulder

1.5

14.0

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery) 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: 25'

LIQUID LIMIT

AFTER DRILLING

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Hollow Stem Auger

671+20, 10' R

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

NOTES:

BORING B16-01

COMPANY:

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: C :\M

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S .G

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7/

Haztech LOGGER: Eric Lim

Rain, low 40's F

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Jason Adams

WEATHER:

PROJECT: Nestucca River Access Road

Automatic

WATER CONTENT (%)

11.7'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

1/15/2016

S A

M P

LE

R

1/15/2016

STATION, OFFSET:

PLASTIC LIMIT

50/5" (5" = 99%)

25/0.5" (3" = 301%)

S-8

S-9

BASALT, green-gray, moist very slow, slightly rough drilling

Boring terminated at a depth of 25 feet. Groundwater encountered at approx. 12' at time of drilling.

21.5

25.0

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery) 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: 25'

LIQUID LIMIT

AFTER DRILLING

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Hollow Stem Auger

671+20, 10' R

20.0

22.0

24.0

26.0

28.0

30.0

32.0

34.0

36.0

38.0

40.0

NOTES:

BORING B16-01

COMPANY:

F ile

: C :\M

Y F

IL

E

S \0

E

R

IX

\0

P R

O

JE

C T

S \O

R \O

R B

LM

S

A L

(1

N E

S T

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C A

R

IV

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\E X

P

LO

R A

T

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N

F

IE

LD

\N

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T U

C C

A G

IN

T

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P

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R A

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S .G

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:\U S

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S \B

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T

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Haztech LOGGER: Eric Lim

Rain, low 40's F

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Jason Adams

WEATHER:

PROJECT: Nestucca River Access Road

Automatic

WATER CONTENT (%)

11.7'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

1/15/2016

S A

M P

LE

R

1/15/2016

STATION, OFFSET:

PLASTIC LIMIT

12 5 6 (12" = 67%)

2 2 2 (18" = 100%)

1 1 2 (16" = 89%)

2 1 1 (15" = 83%)

0 0 0 (18" = 100%)

4 8 50/1" (6" = 46%)

25/0.5" (1" = 100%)

S-1

S-2

S-3

S-4

S-5

S-6

S-7

Silty GRAVEL with sand, medium dense, gray, moist (2" minus gravel surfacing)

Silty SAND to sandy SILT with gravel, medium dense, red-brown, moist, (FILL) rock in tip - N may be overstated becomes sandy silt, soft, moist

Silty SAND, very loose, orange-brown, moist, non-plastic becomes sandy SILT, very soft, orange-brown, wet

BASALT, very dense, green-gray with white specks of zeolite, moist gravelly, slow drilling

3.0

9.5

14.0

20.0

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery) 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: 20'

LIQUID LIMIT

AFTER DRILLING

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Hollow Stem Auger

671+50, 10' L

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

NOTES:

BORING B16-02

COMPANY:

F ile

: C :\M

Y F

IL

E

S \0

E

R

IX

\0

P R

O

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C T

S \O

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S T

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C A

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F

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\N

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P

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S \F

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: 1 /1

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Haztech LOGGER: Eric Lim

Overcast, low 40's F

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Jason Adams

WEATHER:

PROJECT: Nestucca River Access Road

Automatic

WATER CONTENT (%)

12'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

1/15/2016

S A

M P

LE

R

1/15/2016

STATION, OFFSET:

PLASTIC LIMIT

25/0.5" (1" = 100%)

S-8Boring terminated at a depth of 20 feet. Groundwater encountered at approx. 12 feet at time of drilling.

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery) 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: 20'

LIQUID LIMIT

AFTER DRILLING

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Hollow Stem Auger

671+50, 10' L

20.0

22.0

24.0

26.0

28.0

30.0

32.0

34.0

36.0

38.0

40.0

NOTES:

BORING B16-02

COMPANY:

F ile

: C :\M

Y F

IL

E

S \0

E

R

IX

\0

P R

O

JE

C T

S \O

R \O

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LM

S

A L

(1

N E

S T

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C A

R

IV

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\E X

P

LO

R A

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IO

N

F

IE

LD

\N

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A G

IN

T

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P

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R A

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S .G

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:\U S

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LI

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S \B

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T

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\L

IB

R A

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S \F

H W

A

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: 1 /1

7/

Haztech LOGGER: Eric Lim

Overcast, low 40's F

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Jason Adams

WEATHER:

PROJECT: Nestucca River Access Road

Automatic

WATER CONTENT (%)

12'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

1/15/2016

S A

M P

LE

R

1/15/2016

STATION, OFFSET:

PLASTIC LIMIT

1 1 2 (2" = 11%)

0 0 0 (2" = 11%)

0 1 2 (1" = 6%)

1 2 2 (12" = 67%)

2 2 4 (9" = 50%)

10 15 20 (13" = 72%)

27 27 24 (11" = 61%)

26 25 37 (14" = 78%)

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

Silty SAND, very loose, brown, wet (Fill) with angular gravel, non-plastic becomes loose

BRECCIA, sandy, dense, gray, wet

2" tan sandy silt infill

12.0

20.0

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery) 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: 20'

LIQUID LIMIT

AFTER DRILLING

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Casing Advancer

707+70, 20' L

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

NOTES:

BORING B16-03

COMPANY:

F ile

: C :\M

Y F

IL

E

S \0

E

R

IX

\0

P R

O

JE

C T

S \O

R \O

R B

LM

S

A L

(1

N E

S T

U C

C A

R

IV

E R

\E X

P

LO

R A

T

IO

N

F

IE

LD

\N

E S

T U

C C

A G

IN

T

E X

P

LO

R A

T

IO

N L

O G

S .G

C

:\U S

E R

S \P

U B

LI

C

\D O

C U

M E

N T

S \B

E N

T

LE

Y \G

IN

T

\L

IB

R A

R

IE

S \F

H W

A

LI

B R

A R

Y nt ed

: 1 /1

7/

Haztech LOGGER: Eric Lim

Rain, mid 40's F

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Jason Adams

WEATHER:

PROJECT: Nestucca River Access Road

Automatic

WATER CONTENT (%)

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: Dietrich 25

D E

P T

H ft

1/28/2016

S A

M P

LE

R

1/28/2016

STATION, OFFSET:

25/0.5" (0" = 0%)

S-9Boring terminated at a depth of 20 feet. No groundwater encountered at time of drilling.

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery) 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: 20'

LIQUID LIMIT

AFTER DRILLING

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Casing Advancer

707+70, 20' L

20.0

22.0

24.0

26.0

28.0

30.0

32.0

34.0

36.0

38.0

40.0

NOTES:

BORING B16-03

COMPANY:

F ile

: C :\M

Y F

IL

E

S \0

E

R

IX

\0

P R

O

JE

C T

S \O

R \O

R B

LM

S

A L

(1

N E

S T

U C

C A

R

IV

E R

\E X

P

LO

R A

T

IO

N

F

IE

LD

\N

E S

T U

C C

A G

IN

T

E X

P

LO

R A

T

IO

N L

O G

S .G

C

:\U S

E R

S \P

U B

LI

C

\D O

C U

M E

N T

S \B

E N

T

LE

Y \G

IN

T

\L

IB

R A

R

IE

S \F

H W

A

LI

B R

A R

Y nt ed

: 1 /1

7/

Haztech LOGGER: Eric Lim

Rain, mid 40's F

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Jason Adams

WEATHER:

PROJECT: Nestucca River Access Road

Automatic

WATER CONTENT (%)

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: Dietrich 25

D E

P T

H ft

1/28/2016

S A

M P

LE

R

1/28/2016

STATION, OFFSET:

1 2 1 (8" = 44%)

2 2 3 (10" = 56%)

1 5 6 (13" = 72%)

6 7 6 (11" = 61%)

5 6 7 (10" = 56%)

25 40 27 (12" = 67%)

21 30 30 (12" = 67%)

17 7 6 (5" = 28%)

S-1

S-2

S-3

S-4

S-5

S-6

S-7

S-8

Silty SAND with gravel, angular to subangular, very soft, brown, moist, (Fill)

Becomes slightly plastic, soft, light brown

Auger refusal. Start casing advancer.

Becomes very stiff

Drill pump breakdown. stop for day. Restart on 1/28/2016.

Silty GRAVEL with sand, black subangular basalt, brown silty sand matrix, very dense, wet (Fill)

Sandy SILT, stiff, orange-brown, wet, scattered pebble-sized subangular gravel

12.5

18.0

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery) 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: 31.5'

LIQUID LIMIT

AFTER DRILLING

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Casing Advancer

719+10, 20' L

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

NOTES:

BORING B16-04

COMPANY:

F ile

: C :\M

Y F

IL

E

S \0

E

R

IX

\0

P R

O

JE

C T

S \O

R \O

R B

LM

S

A L

(1

N E

S T

U C

C A

R

IV

E R

\E X

P

LO

R A

T

IO

N

F

IE

LD

\N

E S

T U

C C

A G

IN

T

E X

P

LO

R A

T

IO

N L

O G

S .G

C

:\U S

E R

S \P

U B

LI

C

\D O

C U

M E

N T

S \B

E N

T

LE

Y \G

IN

T

\L

IB

R A

R

IE

S \F

H W

A

LI

B R

A R

Y nt ed

: 1 /1

7/

Haztech LOGGER: Eric Lim

Rain, mid 40's F

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Jason Adams

WEATHER:

PROJECT: Nestucca River Access Road

Automatic

WATER CONTENT (%)

24'

WATER…