GM_15-18_Design_&_Construction_Recommendations.pdf

Western Federal Lands Highway Division 610 E. Fifth Street

Vancouver, WA 98661 Phone 360-619-7700

Fax 360-619-7846

DATE: June 7, 2018

TO: Matt Miller Project Manager

FROM: Robert Kraig Geotechnical Engineer

SUBJECT: Geotechnical Memo 15-18 Geotechnical Design & Construction Information Snoqualmie Repairs 2016

WA FS ERFO 2016(1)-20(4)

Mt. Baker-Snoqualmie National Forest, WA

INTRODUCTION

In July 2017, the Western Federal Lands Highway Division (WFLHD or WFL) conducted site reconnaissance to investigate incurred damage to forest roads in the Mt. Baker-Snoqualmie National Forest, Washington. This memorandum contains geotechnical and construction recommendations for the damage sites located on Forest Development Roads (FDR):

• 5200 at milepost (MP) 6.1;

• 5640 at MP 0.04;

• 5700 at MP 23.03;

• 7810 MP 0.1;

Although information is provided in this memorandum for all the sites listed above, the primary purpose of the memorandum is to provide geotechnical design and construction information for the mitigation at the FDR 5200 MP 6.1 and FDR 5700 MP 23.03 sites, which are described in the greatest detail.

An additional damage site (9000216-0.132) was added to the project after the WFLHD Geotechnical Section visited the sites in July 2017. It is our understanding that geotechnical assessment is not required for this site; consequently, this memorandum contains no information pertaining to that site.

PROJECT DESCRIPTION

The four (4) sites addressed in this memorandum are part of a larger regional damage event that recently qualified for assistance under the Emergency Relief of Federally Owned Roads (ERFO) program due to damage sustained during the winter of 2015/2016. Figure 1 shows the general location of the project sites in northwest Washington. The sites are in the Mt. Baker-Snoqualmie National Forest (Forest) located in King County. The sites range from about 50 to 80 miles driving distance from Seattle (approximately 1 to 2 hours driving time), and are located along narrow forest road corridors. Site Local Vicinities are shown in Figures 2a through 2d.

Figure 1: Project location relative to Seattle, Tacoma and Everett, WA.

Figure 2a: Site vicinity of FDR 5200 MP 6.1 relative to Lester, WA.

(Image captured from 7/2017 Google Earth imagery)

Project Location

Figure 2b: Site vicinity of FDR 5640 MP 0.04 relative to North Bend, WA.

Figure 2c: Site vicinity of FDR 5700 MP 23.03 relative to Skykomish, WA.

Figure 2d: Site vicinity of FDR 9035 MP 0.8 relative to Snoqualmie Pass, WA.

GEOLOGY

Geologic map excerpts described under this section were obtained from three separate geologic maps obtained through the USGS online National Geologic Map Database. The geologic maps used are listed under the figures and under the References at the end of this memorandum. Discussions of the geologic map units follows. The individual sites are shown in Figures 3a through 3d.

FDR 5200 MP 6.1

Figure 3e shows this site to be located in a deposit of alluvium, Qa. (Holocene and Pleistocene) described as:

Moderately sorted cobble gravel along rivers to poorly sorted gravelly sand on small tributary fans;

some fan material is lithologically similar to that included in talus gravels that are perched above present day flood-plain surfaces.

The adjacent valley slopes are comprised of rocks of the Ohanapecosh Formation (Oligocene). The Ohanapecosh Formation (To) is described as:

Well bedded, multicolored, volcanic- and crystal-lithic andesitic tuff and breccia and volcaniclastic sedimentary rocks alternating with massive tuff breccia, subordinate basalt and andesite flows and flow breccia, and minor rhyolite tuff.

Figure 3a: FDR 5200 MP 6.1 shown within excerpt from the

Geologic Map of the Snoqualmie Pass 30 x 60 Minute Quadrangle, Washington

FDR 5640 MP 0.04

Figure 3b shows that the FDR 5640 site is located adjacent to the Taylor River within a mapped surficial deposit of alluvium (Qa) and adjacent to a Glaciolacustrine deposit, Qvgl. Refer to the description for Qa above under FDR 5200 MP 6.1. The Qvgl unit (Pleistocene) is described as:

Bedded silt and clay containing sand lenses and sparse dropstones; present in mountain valleys.

Distinguished on map from other Vashon-age deposits (mainly unit Qvr) only where continuous and thick.

Figure 3b: FDR 5640 MP 0.04 shown within excerpt from Geologic Map of the

Skykomish River 30- by 60- Minute Quadrangle, Washington

FDR 5700 MP 23.03

Figure 3c shows this repair site to be located below (to the southwest of) Prospectors Ridge along Lennox Creek within a unit of Alpine-glacier deposits, Qag (Pleistocene) described as:

Ranges from till upvalley and in uplands to gravelly outwash on broad valley floors; includes areas mostly veneered with drift but having small areas of protruding bedrock or overlying small fans, colluvium, or other discontinuous deposits. Grades into unit Qgp in headward reaches of alpine valleys. (Qgp: glacial and protalus deposits of the Holocene and Pleistocene.)

Based on the geologic mapping, Lennox Creek appears to have eroded in the project vicinity through mapped units of TST (a component of the Snoqualmie batholith), or possibly TKwa (a component of the western mélange belt) as described below.

TST: (Tonalite and granodiorite of the Miocene and Oligocene); Biotite-hornblende tonalite and granodiorite, medium-grained, mostly equigranular, with hypidiomorphic texture; locally contains clinopyroxene. Mostly light-colored (CL 9-24), coarsely jointed rock. Description adapted from Erikson (1969, p. 2218-22-19).

TKwa: (Argillite and graywacke of the early Tertiary to mid-Cretaceous.); Pervasively sheared, scaley matrix of mostly argillite containing steep-sided, outcrop- to mountain-sized clasts of volcanic rocks, altered glass, and plagioclase crystals; also contains clasts of chert, sandstone, and siltstone.

Variabley altered to smectites, epidote, and calcite. Locally hornfelsic near Tertiary plutons, most extensively south of Yongs Creek stock. Near Calligan Lake, unit includes andesite and dacite porphyry dike swarm.

Figure 3c: FDR 5700 MP 23.03 shown within excerpts from Geologic map of the

Skykomish River 30- by 60- Minute Quadrangle, Washington

FDR 9035 MP 0.8

Figure 3d shows this site to be located in a deposit of alluvium, Qa (Holocene and Pleistocene) described as:

Moderately sorted cobble gravel along rivers to poorly sorted gravelly sand on small tributary fans;

some fan material is lithologically similar to that included in talus (unit Qt). Includes postglacial terrace gravels that are perched above present day flood-plain surfaces

Figure 3d: FDR 9035 MP 0.8 shown within excerpt from the

Geologic Map of the Snoqualmie Pass 30 x 60 Minute Quadrangle, Washington

SITE CONDITIONS

Site photographs are provided as Attachment 1 as Photos A1-1 through A1-28.

FDR 5200 MP 6.1 (Approx. coordinates 47.193566° North Latitude, -121.403258° West Longitude)

Damage site photos appear in the attachment as Photos A1-1 through A1-10.

The damage site is located along the Green River in a narrow corridor on a bench cut into the hillside about 100 feet horizontal distance and 40 to 80 feet vertical distance from the river. (Measurements estimated using Google Earth and USGS Topographic maps, respectively). We interpret that surface erosion and saturated soil conditions led to failure during a storm event during the winter of 2015/2016.

The damage extends about 14 feet into the traveled way, thus rendering the road impassible, with length along the outside shoulder of approximately 30 feet. The upper face of the failure appeared slightly damp during our site visit in July 2017 and we observed a small seep in the cut located slightly above ditch line with wet conditions in the ditch. (See Photo A1-3.) We also noted rilling/erosion along the outside of the road originating from the north and leading into far side of the failure zone, which appears to have originated at the next culvert about 350’ ahead. It is likely that the culvert became blocked and/or was overwhelmed and led to the water running along the road back to the failure zone where it scoured over the outside shoulder.

Rock outcrops were observed in cutslope, especially in the cut leading into the damage zone. Bedrock outcrops were not observed in the face of the failure; however, it was encountered in the test borings.

(Assumed to be rock of the Ohanapecosh Formation described under Geology and shown in Photo A1-8.)

FDR 5640 MP 0.04 (Approx. coordinates 47.556336° North Latitude, -121.536511° West Longitude)

Photos for this damage site appear in the attachment as Photos A1-11 through A1-14.

This damage site located about 300 feet (or less) to the east of the Taylor River and is at near river elevation. According to DSR, a debris slide on the main stem of the Taylor River diverted flow across the road and flowed in a channel on the opposite side of the road and caused severe erosion damage in three areas from MP 0.04 to 0.10. (See Photos A1-11, A1-13 and A1-14.) The undamaged portions of the road appear to be comprised of road fill placed over native alluvium. (We interpret that Photos A1-11 and A1-14 show the Qa moderately sorted cobble gravel described under the Geology section.)

The road fill was noted to be “rocky” as shown in Photo A1-13. There is a rock exposure to the right (east) as pointed out in Photo A1-10, which is interpreted to be the toe of Garfield Mountain located to the east and described under the Geology section as volcanic rock (Tv). There is an existing berm that was constructed on the stream side, a portion of which was breached at the time of the damage.

FDR 5700 MP 23.03 (Approx. coordinates 47.652786° north latitude, -121.568961° west longitude)

Damage site photos appear in the attachment as Photos A1-15 through A1-23.

The site is located on the north side of Lennox Creek. High storm flows in the creek eroded into the bank and undermined the road for about 140 feet.

The bedrock, exposed in the channel and in the cuts, appears massive and blocky with moderately to widely spaced discontinuities. (Photos A1-17 and A1-18) We collected a specimen sample from the site for evaluation at the WFLHD office as discussed in the following section. The bedrock exposure at the stream bank was not evident through the entire length of the damaged area with some areas showing exposed soils.

FDR 9035 MP 0.8 (Approx. coordinates 47.395006° North Latitude, -121.469178° West Longitude)

Photos for this damage site appear in the attachment as Photos A1-23 through A1-27.

The site is approximately 3.5 miles direct distance west from Snoqualmie Pass and south of Granite Lookout Mountain. The road shoulder was overwhelmed during high flows in the South Fork Snoqualmie River and failed leaving a precipice at the road’s edge. The site sustained complete loss of the road shoulder for approximately 75 feet. Riprap has been temporarily placed at the precipice.

SUBSURFACE INVESTIGATION

The subsurface investigation for the project consisted of two geotechnical test hole borings drilled by Geotek Alaska, Inc. in late July, 2017. Approximate test hole locations are shown in Figure 4. The test holes were logged by WFLHD personnel at the time of drilling.

The test holes were advanced using a CME-75 truck-mounted drill rig using a 7.625 inch outside diameter (OD) hollow stem auger and/or a casing advancer system. NQ sized rock coring tools were used to obtain core samples when rock was encountered. Standard penetration tests (SPTs) consisting of 2 inch OD standard split spoon samplers were performed at 2.5 foot intervals in soils.

SPT samples were visually classified in the field and at the WFLHD office in Vancouver. Laboratory tests were performed on select samples for soil classification and/or index tests and appear in the discussions below.

FDR 5200 MP 6.1

Test hole boring B17-13 was drilled near the south edge of the failure limits (Photo A1-9) and B17-04 was drilled near the north edge (Photos A1-10). The B17-13 boring was advanced to 20.1 feet below ground surface (BGS) and B17-14 was advanced to 28 feet BGS. Laboratory tests were performed on select samples from each test hole. Approximate test hole locations are shown in Figure 4. Soil profiles and subsurface conditions in each test hole boring are described below. Boring logs and laboratory results are contained in Attachment 2.

B17-13

• Encountered predominantly granular soils overlying bedrock (Breccia).

• 0 to 10.0 feet: Sand with gravel, very loose to very dense, gray, dry to moist, fine to coarse sand, rounded to angular. Noted to be very dense below 7.5 feet.

• 10.0 feet to BOH: Bedrock (Breccia), grayish green with red to green to brown to black clasts, fine to very coarse grained, slightly weathered, weak to medium strong (R2 to R3).

Drilling rate was noted to slow below 14 feet.

• No groundwater was encountered during drilling.

B17-14

• Encountered predominantly granular soils overlying bedrock (Breccia).

• 0 to 11.0 feet: Silty sand with gravel, loose, brown to gray to green, moist, fine to coarse sand. Laboratory testing showed this material to classify as SM in the Unified Soil Classification System (USCS) with a Liquid Limit (LL) of 34 and a Plasticity Index (PI) of 7 (slightly plastic).

• 11.0 feet to BOH: Bedrock (Breccia), grayish green with red to green to brown to black clasts, fine to very coarse grained, slightly weathered, weak to medium strong (R2 to R3).

Discontinuity spacing below 20 feet reported as closely to moderately spaced and in good to excellent condition. Discontinuities ranged from about 0 to 10 degrees from assumed horizontal although a high angle oxidized discontinuity or vug was recorded from 27.2 to 28 feet BGS. RQD ranged from 37% to 62% with CR of 66% to 96%.

• No groundwater was encountered during drilling.

Figure 4: Approximate test hole location at FDR 5200 MP 6.1

FDR 5700 MP 23.03

We did not perform a subsurface investigation at this site; however, a rock specimen was obtained for evaluation following the site visit as shown in Photo A1-23. We assessed the strength of the rock by performing a simple non-laboratory test (field test) using the hammer end of a geologic hammer. We found that many firm blows were required to fracture the specimen or that we were only able to chip the surface using the same effort. According to this test procedure, the specimen had a relative rock strength of very strong (R5) to extremely strong (R6), with R5 representing approximate uniaxial compressive strength of 14,500 to 36,000 pounds per square inch (psi) and R6 representing rock strength of greater than 36,000 psi.

Cursory examinations of the specimen reveal larger crystal structure (coarse grained to very coarse grained), thus indicating an intrusive igneous rock type. Our preliminary evaluation is that the rock type is granodiorite, which corresponds with the geologic mapping discussed Geology section above and is likely a component of the Snoqualmie Batholith.

FDR 5640 MP 0.04 and FDR 9035 MP 0.8

Subsurface investigations were not conducted at these two repair sites.

ANALYSIS

Analysis for this project included site reconnaissance, determination of subsurface conditions, and the selection of the recommended option (discussed below). Additional geotechnical design analyses were not deemed necessary for the project given the level of damage at the sites, the scope of the ERFO program, and our prior experience with similar storm damage in the region. Designs are based on WFLHD standard ERFO design templates and recommendations for the appropriate repairs as discussed below.

DESIGN RECOMMENDATIONS

FDR 5200 MP 6.1

A Reinforced Soil Slope (RSS), Mechanically Stabilized Earth (MSE) Wall, and Special Rock Embankment (SRE) were all considered as potential options for repairing these sites. However, due to lower cost and reduced construction time, a SRE is recommended as the preferred option. A SRE can be constructed as steep as 1:1 to reduce material quantities if reinforcements are used. In this case, it is referred to as a reinforced SRE.

A reinforced SRE consists of placing alternating layers of reinforcement and mechanically placed rock that is benched into the existing slope with a maximum slope face ratio of 1:1 and a geotextile separation fabric placed behind and below the SRE. The SRE may be constructed flatter than 1:1;

however, reinforcements are required for slopes steeper than 1:1.25 (V:H). Anything flatter than 1:1.25 can be constructed unreinforced. A conceptual illustration of a reinforced SRE is shown in Figure 5.

The proposed reinforced SRE for the project repair sites are designed to be constructed at 1:1.25 maximum steepness. At the time of this memo, the anticipated maximum design height for the reinforced SRE is 22 feet. Refer to the final contract plan set for specific design requirements.

Figure 5: Conceptual illustration of a reinforced SRE at 5200 MP 6.1

It is likely that some drainage improvements will be required in ditch at this site.

FDR 5640 MP 0.04

The proposed repair at this site was designed mainly by the WFLHD Hydraulics and Design sections.

It is our understanding that repairs will consist of reconstruction of the road bed using class 2 riprap at two locations (first near the beginning and the second near the end of the damaged zone) and placing unclassified borrow and roadway aggregate, some drainage improvements, and repairing of the damaged portion of the existing berm with unclassified borrow. Refer to the project plan set for specific requirements for the design.

FDR 5700 MP 23.03

The proposed repair at this site was designed by the WFLHD Hydraulics and Design sections. It is our understanding that repairs will consist of placing class 9 riprap at a 1:1 finished face through the damaged zone that will toe into the stream channel and will be capped on top with unclassified borrow.

Refer to the project plan set for specific requirements for the design.

FDR 9035 MP 0.8

The proposed repair at this site was designed by the WFLHD Hydraulics and Design sections. It is our understanding that the repair will consist of bank stabilization using class 5 riprap placed at a 1:1.25 (V:H) finished face and toed into the stream channel that incorporates woody materials such as log deflectors and root wads to create aquatic habitat. Refer to the project plan set for specific requirements for the design.

CONSTRUCTION CONSIDERATIONS

It is our understanding that a Government-provided material source will be available for unclassified borrow for this project. This material source is located nearby the FDR 5640 MP 0.04 site, approximately 1 miles driving distance. Although it is reported that this site has been used in the past on Government projects, the WFLHD did not specifically test this source for the current project and it will be the Contractor’s responsibility to ensure that the source meets the contract requirements for unclassified borrow.

FDR 5200 MP 6.1 (Photos A1-1 through A1-10.

A reinforced special rock embankment, as shown in the conceptual illustration appearing in Figure 5, is the proposed repair for this damage site. The preliminary plans call for a maximum height of approximately 22 feet. Refer to the final contract plan set for specific design requirements.

The site is located within a narrow corridor of the FDR 5200 road that is bounded by steep slopes.

The existing damage at this site reaches about 14 feet into the travel way as can be seen in Photo A1-9 (among others), that may impact construction logistics.

Seeps were noted in the cutslope above the ditch, where standing water was observed during the site reconnaissance performed in July 2017, but seeps were not observed in the face of the failure during the same site reconnaissance. Groundwater was not encountered at the two test holes drilled in late June 2017.

Depending on seasonal conditions, wet conditions may impact construction efforts, including but not limited to allowable benching heights, temporary cutslope ratios and time allowed for the excavation to be open. We recommend construction at this site to commence during the dry season (late July to mid-August) when seepage activity is expected to be at a minimum and to provide increased stability of the temporary cut during construction.

Both test hole borings encountered bedrock at relatively shallow depths (10 feet BGS in B17-13 and 11 feet BGS in B17-14); however, it is not uncommon to encounter bedrock contacts that are irregular.

The Contractor must be prepared to excavate into, and handle, weak to medium-strong bedrock (R2 to R3) with RQD that was shown to vary from 37 to 62, or possibly higher (an auger was used to advance the test holes for much of the drilling depth). Except for the foundation width, it may be possible to reduce the bench widths with approval from the CO for potential bench width reductions into bedrock. In that case the project geotechnical engineer should be notified to evaluate impacts that shorter bench widths may have on the design requirements.

FDR 5640 MP 0.04 (Photos A1-11 through A1-14.

The Contractor should be prepared to scarify into the existing roadbed materials, which appear to be rocky road fill over native alluvium as seen in Photos A1-11, A1-13 and A1-14. Boulders up to 14 inches were observed during the site investigation. It should be expected to encounter boulders that size and larger.

FDR 5700 MP 23.03 (Photos A1-15 through A1-22.

The Contractor must be prepared to handle and place class 9 riprap through this failure zone. The bedrock at this site was estimated to have a relative strength of very strong (R5) to extremely strong (R6), making it impossible to excavate using conventional equipment without drilling and blasting. It is our understanding that benching into intact bedrock will not be required and that placement of the class 9 riprap will be against the existing rock exposures were bedrock is exposed, and keyed into the areas where soil or fragmented rock materials are present. The intent of this repair is to achieve an overall interlocking mass that can withstand erosive forces caused by the stream. Bedrock exposures are likely irregular. See Photos A1-16 and A1-17 for illustrations of possible bedrock exposures.

Like most of the other repair sites this site is in a narrow corridor and loss of some of the travel way may increase construction effort. Pass through construction techniques may be required. It is our understanding that water diversion is required through the construction zone. Refer to the contract documents for water diversion requirements.

FDR 9035 MP 0.8 (Photos A1-23 through A1-27.

The Contractor must be prepared to handle and place class 5 riprap and woody material the extends below stream elevation where it is keyed in at the toe as shown on the plans. It is our understanding that water diversion will be required through the construction zone. Refer to the contract documents for water diversion requirements.

REFERENCES

• Google Earth

• United States Geological Survey (USGS), National Geologic Map Database; online access;

https://ngmdb.usgs.gov/ngmdb/ngmdb_home.html; accessed 5/9/2018.

• Geologic Map of the Skykomish River 30- by 60-Minute Quadrangle, Washington by Tabor, R.W., Frizzell, V.A., Booth, D.B., Waitt, R.B., Whetten, J.T., and Zartman, R.E.: U.S. Geological Survey I-1963, scale 1:100,000.

• Geologic Map of the Snoqualmie Pass 30 x 60 Minute Quadrangle, Washington; R.W. Tabor, V.A. Frizzell, Jr., D.B. Booth, and R.B. Waitt; USGS, 2000

CLOSING

This memorandum was prepared to provide observations made during site reconnaissance, the subsurface investigation results, and geotechnical recommendations for the Snoqualmie Repairs 2016 project on FDR 5200 at MP 6.1, FDR 5640 at MP 0.04, FDR 5700 at MP 23.03 and FDR 9035 at MP

0.8 in Mt. Baker-Snoqualmie National Forest, WA. Professional judgments and recommendations are presented in this memorandum. They are based partly on evaluation of the technical information gathered and partly on the WFLHD Geotechnical Team’s general experience with subsurface and other conditions in the region. It should be noted the explorations, where performed, might not represent potentially unfavorable subsurface conditions beyond the immediate location of the exploration. The observed water levels, and/or conditions indicated on the boring 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.

During construction, if subsurface conditions are encountered that vary from those discussed in this memorandum, or if design loads, project stationing, and/or configurations change, the WFLHD Geotechnical Team should be notified immediately to evaluate what effects, if any, the changes have on the recommendations contained herein. The recommendations presented in this memorandum are applicable only to this specific project as described. These data are not to be used for other purposes.

Please contact Robert Kraig at (360) 619-7699 or robert.kraig@dot.gov with any questions regarding this memorandum.

RK

https://ngmdb.usgs.gov/ngmdb/ngmdb_home.html mailto:robert.kraig@dot.gov

CC: Matt Miller Nathan Jenks

Jim Burke Jennifer Chariarse Jim Neighorn Steve Henry Mike Baron Geotechnical File

Attachments:

1. Project Photos

2. Site Investigation Results

Attachment 1

Site Photographs

(Intentionally blank)

FDR 5200 MP 6.1

Photo A1-1: Looking back to failure zone.

Photo A1-2: Cutside above failure zone.

Photo A1-3: Ditch area behind head of failure zone. Note wet conditions.

Photo A1-4: Looking back over failure zone.

Photo A1-5: Looking ahead over failure zone.

Photo A1-6: Looking up at upper limits of failure zone.

Photo A1-7: Looking down from road into failure zone.

Photo A1-8: Rock outcrop in cut slightly back online. (Ohanapecosh Formation?)

Photo A1-9: Location of the B17-13 test hole.

Photo A1-10: Location of the B17-14 test hole.

FDR 5640 MP 0.04

Photo A1-11: Erosion channels across road. Note possible native alluvium.

Photo A1-12: Bedrock exposure adjacent to damage area. Interpreted to be the toe of the Garfield Mountain.

Rock outcrop

Possible native alluvium

Transverse erosion channel

Photo A1-13: Erosion channel across road. Note rocky road fill.

Photo A1-14: Erosion channel across road. Note possible native alluvium.

Possible native alluvium

Rocky road fill

Transverse erosion channel

Transverse erosion channel

Possible native alluvium

FDR 5700 MP 23.03

Photo A1-15: Looking ahead. (July 2017)

Photo A1-16: Looking ahead. Note possible bedrock exposure. (Dec 2017) bedrock exposure

Predominantly soil exposed

Photo A1-17: Looking back. Note possible bedrock exposure. (Dec 2017)

Photo A1-18: Looking back. (July 2017) bedrock exposure

Photo A1-19: Bedrock exposure on north cut. (July 2017)

Photo A1-20: Bedrock exposure on north cut. (July 2017)

Photo A1-21: Looking across stream at exposure of TKwa. (July 2017)

Photo A1-22: Looking across stream at exposure of TKwa. (July 2017)

Photo A1-23: Specimen of Granodiorite at the project site.

FDR 9035 MP 0.8

Photo A1-24: (July 2017)

Photo A1-25: (July 2017)

Photo A1-26: (July 2017)

Photo A1-27: (July 2017)

Photo A1-28: (July 2017)

Attachment 2

Field Classifications for Soil and Rock Unified Soil Classification System

Soil Descriptive Terminology Rock Descriptive Terms

Boring Logs

(Intentionally blank)

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)

5-2-2 (6" = 33%)

3-2-2 (12" = 67%)

25-35-36 (18" = 100%)

50/6 (6" = 100%)

50/2 (2" = 83%)

50/2 (2" = 83%)

50/1 (1" = 42%)

50/1 (0" = 0%)

S01

S02

S03

S04

S05

S06

S07

S08

Well Graded SAND with gravel, very loose, gray, dry to moist, fine to coarse sand, rounded to angular.

Below 7.5', very dense

BRECCIA, grayish green with red to green to brown to black clasts, fine to very coarse grained, slightly weathered, weak to medium strong (R2 to R3).

Below 14', drill rig chatter and slowed drilling rate.

Below 16', very slow drilling rate.

Bottom of Boring at 20.1'

No groundwater encountered.

10.0

20.1

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 47° 11' 36.48" (47.193467°)

LONGITUDE (DEGREES): W -121° 24' 11.62" (-121.403228°)

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: 20.1'

AFTER DRILLING

Hollow Stem Auger

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Hollow Stem Auger

5200 MP 6.1

0.0

4.0

8.0

12.0

16.0

20.0

24.0

28.0

32.0

36.0

40.0

NOTES:

BORING B17-13

COMPANY:

F ile

: C :\M

Y F

IL

E

S \P

W _P

R O

D U

C T

IO

N

\D

\M

T . B

A K

E R

-S K

Y K

O M

IS

H

-D A

R R

IN

G

T O

N L

O G

S .G

P J

L ib : C

M

Y F

IL

E

S \P

R O

JE

C

T S

\U P

P E

R H

O H

R

IV

E R

R O

A D

\G

IN

T L

O G

S

L A

B R

E S

U

LT

S \F

H W

A

LI

B R

A R

Y .G

LB

ri nt ed

: 1 2/

/2

Geotek Alaska LOGGER: O. George

Mostly Sunny

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

James Beckner

WEATHER:

PROJECT: WA ERFO 2016 (1), WA ERFO 2016(2), WA ERFO 2016(3)

Automatic

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/28/2017

S A

M P

LE

R

6/28/2017

STATION, OFFSET:

Rec. = 66%

RQD = 37%

Rec. = 96%

RQD = 62%

4-3-3 (0" = 0%)

4-3-2 (12" = 67%)

1-1-5 (12" = 67%)

8-30-50/5 (17" = 101%)

50/3 (3" = 83%)

50/2 (2" = 83%)

50/2 (2" = 83%)

50/2 (2" = 83%)

GS01

S02

S03

S04

S05

S06

S07

S08

R1

R2

Silty SAND with gravel, loose, brown to gray to green, moist, fine to coarse sand.

Below 7.5', decreased sand content, increased silt and clay content.

BRECCIA, grayish green with red to green to brown to black clasts, fine to very coarse grained, slightly weathered, weak to medium strong (R2 to R3).

Run 1: Discontinuities are closely to moderately spaced and are in good to excellent condition, CR = 66%, RQD = 37%, FF = 3, discontinuities range from 0 to 10 degrees from assumed horizontal.

Run 2: High angle oxidized discontinuity or vug from 27.2 to 28', stained dark brown. CR = 96%, RQD = 62%, FF = 0.8.

Bottom of Boring at 28'

No groundwater encountered.

11.0

28.0

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 47° 11' 36.84" (47.193567°)

LONGITUDE (DEGREES): W -121° 24' 11.78" (-121.403272°)

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: 28'

LIQUID LIMIT

RQD (%)

AFTER DRILLING

Hollow Stem Auger

NQ Rock Core

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Hollow Stem Auger to 20', NQ Core below 20'

5200 MP 6.1

0.0

4.0

8.0

12.0

16.0

20.0

24.0

28.0

32.0

36.0

40.0

NOTES:

BORING B17-14

COMPANY:

F ile

: C :\M

Y F

IL

E

S \P

W _P

R O

D U

C T

IO

N

\D

\M

T . B

A K

E R

-S K

Y K

O M

IS

H

-D A

R R

IN

G

T O

N L

O G

S .G

J

L ib : C

M

Y F

IL

E

S \P

R O

JE

C

T S

\U P

P E

R H

O H

R

IV

E R

R O

A D

\G

IN

T L

O G

S

L A

B R

E S

U

LT

S \F

H W

A

LI

B R

A R

Y .G

LB

ri nt ed

: 1 2/

/2

Geotek Alaska LOGGER: N. Jenks

Cloudy

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

James Beckner

WEATHER:

PROJECT: WA ERFO 2016 (1), WA ERFO 2016(2), WA ERFO 2016(3)

Automatic

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/29/2017

S A

M P

LE

R

6/29/2017

STATION, OFFSET:

PLASTIC LIMIT

Attachment 2_ Lab Test Results