GM_03-18_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: February 2, 2018

TO: Matt Miller Project Manager

FROM: Robert Kraig Geotechnical Engineer

SUBJECT: Geotechnical Memo 03-18 Geotechnical Design & Construction Information Skykomish Emergency Repairs

WA FS ERFO 2016(1)-20(2)

Mt. Baker-Snoqualmie National Forest, WA

INTRODUCTION

In June and July 2017, the Western Federal Lands Highway Division (WFLHD) conducted site reconnaissance to investigate storm 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 Road (FDR) 6066 at MP 5.59, FDR 6300 at MP 16.6, FDR 6300 at MP 17.2, and FDR 6500 at MP 2.5.

PROJECT DESCRIPTION

The four sites addressed in this memorandum are part of larger regional damage event that recently qualified for assistance under the Emergency Relief of Federally Owned Roads (ERFO) program.

Figure 1 shows the general location of the project sites relative to Everett and Seattle, Washington.

The sites are in the Mt. Baker-Snoqualmie National Forest (Forest) in Snohomish and King Counties, Washington, and range from about 4 to 30 miles driving distance from Skykomish (not visible in the figures). Site vicinities are shown in Figures 2a through 2c.

Figure 1: Project location

Figure 2a: FDR 6066 MP 5.59 (captured from 7/2017 Google Earth imagery)

Project Location

Figure 2b: FDR 6300 MP 16.6 & MP 17.2 (captured from 7/2017 Google Earth imagery)

Figure 2c: FDR 6500 MP 2.5 (captured from 7/2017 Google Earth imagery)

GEOLOGY

Geologic map excerpts described under this section were obtained from the Geologic Map of the Skykomish River 30- by 60-Minute Quadrangle, Washington by R.W. Tabor, V.A. Frizzell, Jr., D.B.

Drainage Channel (former site)

Drainage Channel

Drainage Channel (Redirected location)

Booth, Waitt, J.T. Whetten, and R.E. Zartman, 1993. Discussions of the geologic units are under the sites listed below.

FDR 6066 MP 5.59 & FDR 6500 MP 2.5

FDR 6066 MP 5.59 is located within a mapped unit of Granodiorite (Ksb) as follows:

Granodiorite of the Beckler Peak stocks (early-to-late Cretaceous): Biotite granodiorite, hypidiomorphic-granular to xenomorphic with microcline microperthite. Stocks are commonly highly sheared and cataclastic. See Yeats (1958a, p. 74-77) for further description.

FDR 6500 MP 2.5 is located within a mapped alluvium deposit (Qa) of the Holocene and Pleistocene.

The unit is described as:

Moderately sorted pebble to cobble gravel along rivers to poorly sorted gravelly sand on small tributary fans; some fan material similar to that included in unit Qt.

Figure 3a: FDR 6066 MP 5.59 & FDR 6500 MP 2.5 shown within geologic map excerpt

FDR 6300 MP 16.6 & FDR 6300 MP 17.2

The FDR 6300 sites are located within a mapped Qa with a mapped rock unit (Ktp) shown at the slope at the west of the sites. The Qa unit is described under FDR 6500 MP 2.5. The Ktp unit is described as follows:

Phyllite, semischist, schist, and biotie-hornblende gneiss and amphibolite of the early-to-late Cretaceous.

Ksb

Qa

Figure 3b: FDR 6300 MP 16.6 & MP 17.2 shown within geologic map excerpt

SITE CONDITIONS

Site photographs are provided as Attachment 1.

FDR 6066 MP 5.59

Damage site photos appear in the attachment as Photos 1 through 8.

We interpret that saturated soils resulting from heavy rainfall caused the shoulder and hillside to fail.

There is an 18-inch culvert located immediately east of the failure limits that was observed to be passing water during our site visit. We noted water in the ditch above the culvert during the site visit (Photo 3); however, the WFLHD Hydraulics section reported that the flow is intermittent.

We observed bedrock outcrops (Photos 4, 5, 6, 7) with exposed boulders 4-feet to 5-feet diameter (and possibly larger) in a matrix of silty sand and gravel with cobbles. A subsurface investigation was performed, as discussed later. A possible outcropping of bedrock was observed at about 35 feet (vertical) in the fill slope below the road.

FDR 6300 MP 16.6 & FDR 6300 MP 17.2

The FDR 6300 repair sites are located on the western valley side slope above the North Fork Skykomish River. Both sites are located at natural drainage channels, as shown in Figure 2b.

Reference to Google Earth indicates that the channels extend a mile or more upslope, thus providing great potential for water and debris transport. Site photos are presented in the attachment as Photos 9 through 24.

Qa

FDR 6300 MP 16.6

There is an existing 9-foot by 5-foot corrugated metal pipe arch culvert that became blocked when large debris was carried down the drainage channel during the storm event, filled in the channel, overtopped and eroded the road, and deposited material in the roadway in the vicinity of the channel. Damage site photos are provided as Photos 9 through 17.

As seen in the photos, large debris consisting of timber and boulders is scattered through the damage area. Boulders generally measured 1 to 3 feet, but larger sizes are likely present.

The site is approximately 750 feet horizontal distance from the river and about 120 feet vertical distance above, as measured using Google Earth and USGS topographic mapping.

FDR 6300 MP 17.2 (existing)

Like the MP 16.6 site, a large debris flow down the channel plugged the reported 8-foot culvert at this location. Water scoured alongside the culvert, thus leaving much of it exposed. Reference to Google Earth shows that a channel split occurred approximately 875 feet upslope from the road, thus causing it to shift and cross the road about 150 feet to the south. Debris was deposited on and along the road for about 280 feet. This repair site is shown in Photos 18 through 22. Note the coarse debris consisting partially of timbers, with large boulders also present at the proposed repair location.

Referencing Google Earth and USGS topographic mapping, the site is about 550 feet horizontal distance from, and approximately 120 feet vertical distance above the river.

MP 17.2 (Proposed)

As discussed above, the drainage channel was redirected and now crosses at approximately 150 feet south of the existing culvert location at MP 17.2, as shown in Figure 2b. The redirection resulted in loss of the roadway. Coarse material partially consisting of timbers and large boulders is also present at this location. See Photos 21 through 24.

FDR 6500 MP 2.5

See site Photos 25 through 31.

One or more storm events caused damage to the Beckler River Road in the Skykomish area. The road shoulder was overwhelmed during high flows and failed, leaving a precipice at several locations at the road’s edge. It is assumed that a clogged 36-inch culvert uphill from the failure zone sent ditch flows across the road, thus resulting in embankment damage consisting of complete or limited loss at several locations through the damaged zone.

There is a berm along the edge of road that was formed during the debris clearing operation. We observed large boulders in the embankment that do not appear to be naturally-deposited (see Photos 27, 28, 30 and 31), which might suggest previous failure and repair at this location, or could represent them being incorporated as part of the original embankment construction. In addition to possible incorporation of boulders into the original construction, the embankment appears to contain cohesionless soils that include gravel and cobble-size fragments.

This damage site is located approximately 400 feet horizontal distance from, and 120 feet vertical distance above the Beckler River, as measured using Google Earth and USGS topographic maps.

SUBSURFACE CONDITIONS

The subsurface investigation for the project consisted of two geotechnical test hole borings drilled by Geotek Alaska, Inc. in late June and early July 2017. Test hole B17-12 was drilled at FDR 6066 MP

5.59 and test hole B17-15 was drilled at FDR 6300 MP 16.6. The test holes were advanced to approximately 27.5 feet and 22.5 feet, respectively. Approximate test hole locations are shown in Figures 4a and 4b. The test holes were logged by WFLHD personnel at the time of drilling.

Figure 4a: Approximate test hole location at FDR 6066 MP 5.59

(captured from 7/2017 Google Earth imagery)

Figure 4b: Approximate test hole location at FDR 6300 MP 16.6

(captured from 7/2017 Google Earth imagery)

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 rock coring tools were used to obtain core samples when rock was encountered. Standard Penetration Tests (SPTs) were performed at 2.5- foot intervals where possible. SPT samples were visually classified in the field and at the WFLHD office in Vancouver. No laboratory tests were performed on the samples.

Groundwater, when encountered, was recorded on the boring logs.

FDR 6066 MP 5.59

Test hole boring B17-12 was drilled at this site at the inside edge of the graveled travel way approximately 13 feet from culvert. The boring was advanced to 27.5 feet bgs.

The return flow in the boring was reported to be lost almost immediately after starting the NQ coring at about 7.5 feet bgs. Groundwater was not reported on the boring log; however, at the end of drilling water was noted at 9.5 feet bgs but was assumed to be the product of the drilling fluid used in the investigation. Possible seeps were reported coming out of the embankment slope about 20 feet below road grade.

The test boring encountered loose, silty gravel with sand with gravel up to 1.5 inches in the first 4 feet bgs underlain by medium-strong (R3), light gray, diorite bedrock with closely to moderately spaced discontinuities and rock quality designation (RQD) ranging from 47 percent in the upper region of the rock and increasing to 98 percent with depth.

Test hole boring B17-15 was drilled approximately 150 feet south of the existing culvert at FDR 6300 MP 16.6. The FDR 6300 MP 17.2 site was not accessible due to the damage at the MP 16.6 site and the scope of the drilling contract. However, we anticipate that the subsurface conditions and geology are similar to the conditions that were encountered in the MP 16.6 test boring based on the geologic mapping and visual assessments of the sites.

The test boring was advanced to 22.5 feet bgs and encountered predominantly cohesionless materials consisting of medium dense, well graded sand to approximately 15 feet bgs underlain by dense, well graded gravel with sand to the bottom of the boring at approximately 22.5 feet. Scattered cobbles and possible boulders were reported on the log.

Groundwater was recorded at 14.5 feet bgs with augers in and dropped to 16.5 feet bgs with augers out.

ANALYSIS

Geotechnical design analyses were not deemed necessary for the project given the level of damage at the sites. Designs are based on WFLHD standard ERFO design recommendations for the appropriate repair as discussed below.

DESIGN RECOMMENDATIONS

FDR 6066 MP 5.59 & FDR 6500 MP 2.5

A Reinforced Soil Slope (RSS), Mechanically Stabilized Earth (MSE) Wall, and Special Rock Embankment (SRE) were all considered to be appropriate options for repairing these sites.

However, due to lower cost and reduced construction time, we recommend a SRE 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. The special rock embankment may be constructed flatter; however, reinforcements are still required for slope steepness up to 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 is designed to be constructed at 1:1 steepness. Refer to the final contract plan set for specific design requirements.

Figure 5: Conceptual illustration of a reinforced SRE at 2700 MP 6.9

The proposed AOP precast box culverts and wingwalls were designed by the WFLHD Hydraulics section for these two repair sites. The proposed culverts will measure approximately 20 feet by 16 feet. We provided allowable bearing pressure for both locations to the Hydraulics Section as 5 tons per square foot (tsf) in an email dated October 11, 2017.

Refer to the contract documents for specific design requirements pertaining to the AOP box culverts.

CONSTRUCTION CONSIDERATIONS

FDR 6066 MP 5.59 (Photos 1 through 8)

The corridor is narrow through this repair site, as can be seen in the photos. There is a culvert located nearby with reported intermittent flow. Water was observed present in the ditch above the culvert, but might not exist during the dry season. Bedrock outcrops and exposed boulders of 4-feet to 5-feet estimated diameter are present.

The SRE proposed for this site requires benching into the damaged embankment. The Contractor must be prepared to excavate into medium-strong (R3) bedrock with closely to moderately spaced discontinuities and have equipment large enough to handle the boulders. Bench widths may be reduced with the permission of the CO where competent bedrock is encountered.

FDR 6300 MP 16.6 & FDR 6300 MP 17.2 (Photos 9 through 24)

The Contractor must be prepared to handle large boulders that have washed down from the drainage channel. Most of the boulders are thought to be on the surface since none were encountered in the nearby boring. However, encountering boulders while excavating for footing construction should not be ruled out. Encountering bedrock for the proposed footing elevations is not anticipated at these repair sites. Note that a subsurface investigation was not performed at the MP 17.2 site, as discussed earlier in this memorandum.

FDR 6500 MP 2.5 (Photos 25 through 31)

Large boulders are exposed in the damaged embankment at this repair site. The Contractor must be prepared to handle large boulders to construct the planned SRE. Bedrock is not anticipated at this repair site.

REFERENCES

• Google Earth

• Geologic Map of the Skykomish River 30- by 60-Minute Quadrangle, Washington by R.W.

Tabor, V.A. Frizzell, Jr., D.B. Booth, Waitt, J.T. Whetten, and R.E. Zartman, 1993USGS Topographic Maps

CLOSING

This memorandum was prepared to provide observations made during site reconnaissance, the subsurface investigation results, and geotechnical recommendations for the Skykomish Emergency Repairs project on FDR 6066 at MP 5.59, FDR 6300 at MP 16.6, FDR 6300 at MP 17.2, and FDR 6500 at MP 2.5 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 area. 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 in order 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

CC: Matt Miller Nathan Jenks Jim Burke Jim Neighorn Chris Kelly Jennifer Chariarse Steve Henry Geotechnical File

Attachments:

1. Site Photos

2. Subsurface Investigation Results mailto:robert.kraig@dot.gov

Attachment 1

Site Photos

(Intentionally blank)

FDR 6066 MP 5.59

Photo 1: FDR 6066 MP 5.59 looking west across site

Photo 2: FDR 6066 MP 5.59 looking east across site

Photo 3: FDR 6066 MP 5.59 standing water in ditch immediately east of failure

Photo 4: FDR 6066 MP 5.59 Possible bedrock outcrop visible in backstation ditch

Photo 5: FDR 6066 MP 5.59 Possible bedrock outcropping in driving surface

Photo 6: FDR 6066 MP 5.59 Possible bedrock outcropping visible at culvert inlet

Photo 7: FDR 6066 MP 5.59 Possible bedrock outcropping visible at culvert outlet

Photo 8: FDR 6066 MP 5.59 residual soils weathered to coarse-grained

FDR 6300 MP 16.6

Photo 9: FDR 6300 MP 16.6 looking up the drainage channel

Photo 10: FDR 6300 MP 16.6 looking up the drainage channel.

Note 9’ x 5’ corrugated metal pipe arch culvert.

Photo 11: FDR 6300 MP 16.6 looking south across site.

Photo 12: FDR 6300 MP 16.6 looking south. Note 9’ x 5’ corrugated metal pipe arch culvert.

Photo 13: FDR 6300 MP 16.6 looking over outlet side.

Photo 14: FDR 6300 MP 16.6 looking up at outlet.

Photo 15: FDR 6300 MP 16.6 cobble and boulder-size fragments. Larger fragments exist.

Photo 16: FDR 6300 MP 16.6 cobble and boulder-size fragments. Larger fragments exist.

Photo 17: FDR 6300 MP 16.6 cobble, boulder-size fragments. Larger fragments exist.

FDR 6300 MP 17.2 (existing/old location)

Photo 18: FDR 6300 MP 17.2 (existing location) looking upstream of the drainage channel.

Photo 19: FDR 6300 MP 17.2 (existing location) looking downstream of the drainage channel.

Photo 20: FDR 6300 MP 17.2 (existing location) noting boulder-size fragments.

Photo 21: FDR 6300 MP 17.2 (existing location) looking across site to new AOP culvert location.

FDR 6300 MP 17.2 (Proposed AOP location)

Photo 22: FDR 6300 MP 17.2 looking ahead at new AOP culvert location.

Photo 23: FDR 6300 MP 17.2 view upstream at proposed new AOP location. Note boulders.

Photo 24: FDR 6300 MP 17.2 (Proposed AOP location) Note boulders.

FDR 6500 MP 2.5

Photo 25: FDR 6500 MP 2.5 looking at the site from the southwest

Photo 26: FDR 6500 MP 2.5 close up of one failure viewed from the southwest

Photo 27: FDR 6500 MP 2.5 close up of one failure viewed from the southwest

Photo 28: FDR 6500 MP 2.5 close up view of another embankment slope. Note large boulders.

Note large boulder

Photo 29: FDR 6500 MP 2.5 view of failure zone from the northeast

Photo 30: FDR 6500 MP 2.5 view of failure zone from the northeast. Note boulders.

Note large boulder

Photo 31: FDR 6500 MP 2.5 looking up toward road from below

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)

Rec. = 96%

RQD = 47%

Rec. = 98%

RQD = 87%

Rec. = 91%

RQD = 85%

Rec. = 98%

RQD = 98%

7-6-3 (9" = 50%)

50/.5" (0" = 0%)

50/.5" (0" = 0%)

SPT1

SPT2

SPT3

R1

R2

R3

R4

Silty GRAVEL with sand, loose, dark brown, moist, subangular to angular, gravel to up 1 1/2" in diameter. A few small pieces of wood.

From 2.5 to 4', some organic material coming out in cuttings at start of run. Dusty fine sand to small gravel sized rock fragments coming out in cuttings.

DIORITE, light gray, coarse grained, fresh, medium strong rock (R3).

Run 1: Discontinuities are closely to moderately spaced and are in good condition, FF = 3.5, RCT = 28 minutes, discontinuities range 0 to 5 degrees relative to horizontal. Lost return flow almost immediately after starting coring at 7.5'.

Run 2: Discontinuities are moderately spaced, FF = 1.8, RCT = 20 minutes.

Run 3: FF = 1.5, RCT = 16 minutes. Fracture zone at 20 to 20.5'.

Run 4: FF = 1.25, RCT = 15 minutes.

Bottom of Boring at 27.5'

At end of drilling, water level observed at 9.5' BGS. Value not trusted as water was used for coring and no water/seep was visible in cut slope at this well. Seeps appear to be coming out of fill/slope at 20' vertical below road level.

4.0

27.5

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 47° 43' 29.87" (47.724963°)

LONGITUDE (DEGREES): W -121° 16' 57.46" (-121.282628°)

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: 27.5'

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

Casing Advancer to 7.5', NQ Core below 7.5'

6066 MP 5.59

0.0

4.0

8.0

12.0

16.0

20.0

24.0

28.0

32.0

36.0

40.0

MP 5.6, Photos 322-332, At staked location, on inside (left) edge of graveled road, approx. 13' BOA from culvert. Water level after drilling is 9.5 bgs, but this is influenced by coring fluid. Water is seeping out of failure at a point approximately 20 vertical feet down from the roadway elevation.

NOTES:

BORING B17-12

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Geotek Alaska LOGGER: N. Jenks

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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)

7/1/2017

S A

M P

LE

R

7/1/2017

STATION, OFFSET:

2-3-4 (11" = 61%)

5-6-5 (11" = 61%)

8-9-8 (4" = 22%)

10-13-14 (10" = 56%)

70/6" (5" = 28%)

44-17-26 (7" = 39%)

35-54-65 (12" = 67%)

50/3" (0" = 0%)

9-24-50/1.5"

SPT1

SPT2

SPT3

SPT4

SPT5

SPT6

SPT7

SPT8

SPT9

ROADWAY AGGREGATE, 6" thick Well graded SAND with silt and gravel, loose, brown, moist, subangular, gravel to up 3/4" in diameter. FILL.

Well graded SAND with silt and gravel, loose, brown, moist, subangular, gravel up 3/4" in diameter.

At 2', grinding on cobble. Adjusted location of auger.

Well graded SAND with gravel, medium dense, brown, moist, subangular to angular, gravel to up to 1/2" in diameter.

Well graded SAND with silt, medium dense, brown, moist, subangular to angular, trace gravel up to 1.5" in diameter, coarse gravel stuck in sampler tip.

Well graded SAND with gravel, medium dense, light brown, moist, subangular to angular, gravel up to 1 in diameter.

At 11', drill rig grinding on a cobble or boulder, a 5" diameter cobble came up in cuttings at 12.0'.

Below 12.5', very dense, brown, moist, subangular, gravel up to 1/2" in diameter, trace silt, rock fragments in sampler tip, likely pounding on cobble.

Well graded GRAVEL with sand, dense, gray, wet, angular, gravel up to 1 1/2" in diameter.

Below 17.5', trace silt, very dense, gray, wet, angular to subangular, gravel up to 1 1/4" in diameter.

At 20', no recovery, on cobble or boulder.

Run 1: Cobble, subangular to subrounded, gravel diameter ranges from 1/2 to 2", possible boulders. CR = 48%, RCT = 11 minutes. Alternating hard/soft drilling.

Poorly graded SAND with gravel and cobbles, dense, gray, wet, subangular, gravel up to 2" in diameter, possible boulders. Sample is not representative, may contain slough.

Bottom of Boring at 22.51

0.5

2.0

5.0

7.5

10.0

15.0

21.9 22.5

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 47° 54' 37.98" (47.91055°)

LONGITUDE (DEGREES): W -121° 18' 48.42" (-121.31345°)

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: 22.5'

AFTER DRILLING

Casing Advancer

Hollow Stem Auger

NQ Rock Core

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

Hollow Stem Auger to 13.75', Casing Advancer from 13.75 to 20', NQ Core below 20'

6300 MP 17.2

0.0

4.0

8.0

12.0

16.0

20.0

24.0

28.0

32.0

36.0

40.0

MP 17.2, Photos 299-321,At staked location, 7" from stake at edge of gravel road. Boring located 152' from cener of existing (damaged) culvert, BOA, on fill side of road, GPS point not collected

NOTES:

BORING B17-15

COMPANY:

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2" OD Split Spoon (SPT)

Geotek Alaska LOGGER: N. Jenks

Sunny

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

James Beckner

WEATHER:

16.5'

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

Automatic

14.5'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/30/2017

S A

M P

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6/30/2017

STATION, OFFSET: