GM34-17_PH-1_Geotechnical_Recommendations.pdf

Memorandum

Western Federal Lands Highway Division 610 E. Fifth Street

Vancouver, WA 98661-3801

Date: January 9, 2018

In Reply Refer To: HFL-17 GM 34-17

From: Robert Kraig Geotechnical Engineer

To: Betty Chon Project Manager

Subject: Geotechnical Information & Construction Recommendations— Darrington Emergency Repairs

2016, PH-1,

WA FS ERFO 2016(1)-20(3)

Geotechnical Memorandum GM 34-17

INTRODUCTION

The purpose of this memorandum is to provide geotechnical information and construction recommendations for the subject project. The project consists of fifteen repair sites requiring culvert replacements, and/or embankment reconstruction, and/or road reconditioning. Of the fifteen repair sites, only two require substantive geotechnical assessment and recommendations. The sites requiring this assessment are Forest Development Road (FDR) 2700 at milepost (MP) 6.9, where a Special Rock Embankment is proposed, and FDR 2800 at MP 5.3, where a culvert replacement is proposed. Geotechnical subsurface investigations were performed at both repair sites.

PROJECT DESCRIPTION

The repair sites are essentially in mountainous terrain located on the west flank of the North Cascades Range, northeast of Seattle, Washington, near Darrington. The FDR 2700 MP 6.9 site is in Snohomish County, east-southeast of Darrington, approximately 18 miles (about 1 hour) driving distance. The FDR 2800 MP 5.3 site is located in Skagit County, north-northwest of Darrington, about 9 miles (roughly 30 minutes) driving distance. The repair sites are shown in Figures 1, and 2a and 2b.

Figure 1: Location of repair sites

Figure 2a: Vicinity of the of the FDR 2700 MP 6.9 repair site

Figure 2b: Vicinity of the FDR 2800 MP 5.3 repair site

GEOLOGY

The North Cascades are generally characterized by exposure of plutonic and metamorphic rocks that are resistant to erosion, display great relief, and show evidence of pronounced uplift and recent glaciation. The project sites are shown in Figures 3a and 3b within excerpts from the geologic mapping that is referenced in the figure descriptions. Reference to the figures shows that the 2700 MP 6.9 site is located at the interface of Qag and Kng mapped units and the 2800 site is situated within a Krs mapped unit. A description of the units follows.

North Fork Stillaguamish River

Figure 3a: Location of FDR 2700 MP 6.9 shown within an excerpt from Geologic Map of the Sauk River 30- by 60-minute Quadrangle, Washington, R.W. Tabor, D.B. Booth, J.A. Vance, and A.B. Ford, 2002

Figure 3b: Location of FDR 2800 MP 5.3 shown within an excerpt from Geologic Map of the Sauk River 30- by 60-minute Quadrangle, Washington, R.W. Tabor, D.B. Booth, J.A. Vance, and A.B. Ford, 2002

Qag

Kng

Krs

Qag—Alpine glacial deposits (Holocene and Pleistocene)

These glacial deposits are described as “deposits ranging from boulder till in uplands and up-valley to gravel or sand outwash on broad valley floors. On valley sides and uplands, includes areas veneered with drift, but also includes bedrock, alluvial fans, colluvium, or talus deposits.

On valley floors, also includes small fans, bogs, and modern stream alluvium. Areas of thin, sparse drift not distinguished from bedrock.”

Kng—Nason Ridge Migmatitic Gneiss (Late Cretaceous)

Described as “in south, mostly heterogeneous light-colored tonalite to granodioritic gneiss interlayered with mica schist and amphibolite similar to the Chiwaukum Schist and some ultramafic rock (Ksc). Predominantly crystal-loblastic. Most common lithology is medium-grained biotite gneiss with a slightly porphyroblastic appearance due to anasto-mosing mica layers surrounding larger plagioclase crystals or aggregate grains. Contacts between gneiss and schist are both sharp and gradational along and across strike. Cross-cutting sills, dikes, and irregular bodies of light-colored, fine-grained to pegmatitic tonalite and gneiss are also abundant in migmatitic phases. Most of unit has 50 percent or more light-colored gneiss.

Grades northward into more uniform, mostly medium grained garnet-biotite-quartz-oligoclase (or andesine) gneiss which is difficult to distinguish from Chiwaukum Schist. Rare rounded relict kyanite and sillimanite occur within sericite knots.”

Krs—Slate of Rinker Ridge (Cretaceous)

Predominantly gray to brown, little-recrystallized slate and phyllite with local foliated sandstone and semischist.

SITE CONDITIONS

The Western Federal Lands (WFLHD) Design Team performed site reconnaissance in September, 2016 to assess damage at the sites, collect data, and evaluate for appropriate repairs. Photographs taken during the site visit are contained in Attachment 1.

FDR 2700 MP 6.9

It appears that the site is located within an unpaved section of roadway. It is thought that debris flow plugged a culvert further up the road from the failure zone, thus resulting in water flowing down the toe of the cutslope to the damaged section where it was blocked and partially directed over the road by a downed tree that is lying across the ditch (Photos 1 and 3). This resulted in erosion of the road and embankment, with debris up to about 2 feet deep being deposited on the road for approximately 780 feet. The erosion took out the full road width for about 35 feet, reaching to the inside ditch. Several other lesser failures were noted in the immediate vicinity, with this site being the most severe. There is a steep vegetated slope above the failure zone that appeared to be stable. Depositional material consisting of cobbles and small boulders were observed through center of the failure as can be seen in Photos 2 and 4 through 6. No seeps were observed during the reconnaissance.

FDR 2800 MP 5.3:

This damage site is located near the North Fork Stillaguamish River, which lies slightly to the east, as shown in Figure 2b. It is probable that the culvert inlet became blocked (Photo 14), thus resulting in complete loss of the embankment as can be seen in Photo 9. The top of culvert near the inlet side is seen in Photo 13. The damage at this site is approximately 75 feet wide at the top, 34 feet wide at the bottom, and about 25 feet deep.

Bedrock outcropping was observed on the south side as can be seen in Photos 9, 10 and 12.

Interpreted bedrock outcrops were noted near the bottom of the failure as seen in Photos 11, 13, and 14.

It is our understanding that the site in not accessible from the south; thus, all observations were made from the edge of the failure at the north side.

SUBSURFACE CONDITIONS

The subsurface investigation for the project consisted of two geotechnical test hole borings drilled by Geotek Alaska, Inc. in early July 2017. Test hole B17-09 was drilled at FDR 2700 MP

6.9 and test hole B17-10 was drilled at FDR 2800 MP 5.3. The test holes were advanced to approximately 56 feet and 42 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: B17-09 test hole location at FDR 2700 MP 6.9

Figure 4b: B17-10 test hole location at FDR 2800 MP 5.3

The test holes were advanced using a CME-75 truck-mounted drill rig using a 7 5/8-inch outside diameter (OD) hollow stem auger. NQ rock coring tools were used for the last 2 feet of the FDR 2800 MP 5.3 (B17-10) test hole to obtain a rock core sample. Standard Penetration Tests (SPTs) were performed at intervals ranging from every 2.5 feet in the upper 20 feet to every 5 feet below 20 feet. SPT samples were visually classified in the field with laboratory tests performed at the WFLHD office as described below. Groundwater was not encountered in either of the test holes.

FDR 2700 MP 6.9

The test hole at 2700 MP 6.9 (B17-09) was drilled on the east side of the failure and encountered granular soils for the full depth of the test hole (about 56 feet). Select samples were submitted to the WFLHD laboratory for sieve analysis and classification tests. Samples SPT2, SPT3 and SPT4 were combined to represent the material encountered between 5.0 and

11.5 feet. (The material encountered above 5.0 feet appeared to be like the material encountered between 5.0 and 11.5 feet.) Samples SPT8 and SPT9 were combined to represent the material encountered below 11.5 feet to the bottom of the test hole.

The test boring and laboratory results show that the test hole encountered loose, well-graded sand with silt and gravel (SW-SM) above 20 feet, and dense, silty sand with gravel (SM) below 20 feet. The gravel generally consisted of 1.5-inch minus material and a few cobbles were encountered above about 25 feet. Silt size particles (material passing the #200 sieve) was generally less than 15%, with silt content increasing with depth. Laboratory results are contained in Attachment 2.

The material encountered in this test hole is consistent with the geologic mapping.

FDR 2800 MP 5.3

The test hole at 2800 MP 5.3 (B17-10) was drilled near the failure edge leading in from the north. The test hole encountered loose, well-graded sand in the upper 4 feet of the test hole that was underlain by very weak to weak (R1 to R2) metamorphic bedrock (Phyllite), although increasing drilling difficulty was reported with depth below approximately 13 feet to the point where hard slow drilling was reported near the bottom of the test hole between 35 and 40 feet. Platy foliation of the rock was reported to be about 40 to 55 degrees from the horizontal, which appears to be representative of the orientation of the discontinuities in the rock exposures visible in Photos 9 and 10.

What was encountered in the B17-10 test hole is consistent with the geologic mapping and consistent with what was observed across the failure (east side) and shown in Photos 9 and 10.

DESIGN RECOMMENDATIONS

FDR 2700 MP 6.9

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

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 reinforced SRE for the project was 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 WFLHD Hydraulics Engineering section has proposed an open-bottom arch structure to replace the culvert at this site. It is our understanding that the arch structure will be on cast-in-place or precast footings that are embedded into bedrock at least 1 foot. The rock at this site is considered to have sufficient bearing capacity for the type of structure proposed. The presumptive bearing pressure for the rock at this site was provided to the WFLHD Hydraulics team at 8 tons/ft2. This presumptive value was obtained from Table 1 appearing in the Naval Facilities Engineering Command Design Manual (NAVFAC DM-7.2) for compaction shale or other highly argillaceous rock in sound condition with an allowable range of 8 to 12 tons/ft2.

The lower value (8 tons/ft2) was assumed for this site owing to the condition of the rock.

Refer to the final contract plans for specific requirements for the arch structure.

CONSTRUCTION CONSIDERATIONS

FDR 2700 MP 6.9

Excavation for the reinforced SRE at this site is anticipated to be in predominantly granular materials. As described earlier, cobbles and boulders have been deposited within the repair limits at this site. Although boulders were not encountered in the test hole, it is possible that boulder-size rock fragments could be encountered. The Contractor should be prepared to excavate boulder-size material, if encountered.

Excavation into bedrock will be required to ensure that the footings are founded on competent rock according to Section 208 in the Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects (FP-14). The boring at the north side of this site encountered very weak to weak bedrock (R1 to R2) in the upper portion of the test hole (at about 13 feet bgs); however, it was noted that the drilling did become more difficult with depth—especially below about 30 feet bgs, although the rock was still able to be augured at that depth. A core sample with recovery of 21 inches over 1.9 feet (about 23 inches) was obtained at the bottom of the test hole. The RQD of the sample is reported as zero (RQD is the percentage of rock fragments greater than 4 inches in length), thus indicating highly fractured rock at that depth.)

The Contractor should be prepared to excavate into R1 to R2 rock with discontinuity orientation up to about 55 degrees from the horizontal. It is our opinion that the rock is excavatable using an appropriately-sized hydraulic excavator fitted with cutting teeth. The Contractor should also be aware that zones of stronger rock may be present within the excavation limits, thus requiring the use of a hydraulic splitter, or other appropriate means. It is our understanding that rock blasting will not be permitted on this project.

As discussed earlier it is our understanding that this site is not accessible from the south.

CLOSING

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

cc: Betty Chon Katie Alexander

Sven Leon Jim Neighorn Benn Oltmann Jennifer Chariarse Stephen Henry

Geotechnical File

Attachments: 1 - Site Photographs 2 - gINT Logs & Lab Results mailto:robert.kraig@dot.gov

Attachment 1

Site Photographs

(Intentionally blank)

Photo 1: FDR 2700 6.9 looking ahead toward failure zone

Photo 2: FDR 2700 6.9 looking into failure zone (ahead)

Photo 3: FDR 2700 6.9 looking back on failure zone (back). Note obstruction at ditch line.

Photo 4: FDR 2700 6.9 looking down failure zone

Photo 5: FDR 2700 6.9 looking back into failure zone

Photo 6: FDR 2700 6.9 looking down failure zone

Photo 7: FDR 2700 6.9 looking back across failure zone

Photo 8: FDR 2800 5.3 looking back (south) to failure zone

Photo 9: FDR 2800 5.3 looking over failure zone from the north

Photo 10: FDR 2800 5.3 Phyllite bedrock outcrops on west side of failure

Discontinuity orientation approx. 55o from horizontal

Photo 11: FDR 2800 5.3 looking at base of failure near culvert inlet

Photo 12: FDR 2800 5.3 Downstream of the outlet

Photo 13: FDR 2800 5.3 top of buried culvert

Photo 14: FDR 2800 5.3 culvert inlet

Attachment 2

Field Classifications for Soil and Rock Unified Soil Classification System

Soil Descriptive Terminology Rock Descriptive Terms

Boring Logs

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)

5-3-2 (11" = 61%)

6-4-3 (5" = 28%)

2-3-5 (9" = 50%)

8-7-6 (8" = 44%)

5-7-12 (11" = 61%)

8-10-10 (13" = 72%)

10-11-10 (9" = 50%)

4-11-29 (10" = 56%)

12-13-24 (12" = 67%)

10-11-11 (14" = 78%)

17-18-22 (12" = 67%)

SPT1

SPT2

SPT3

SPT4

SPT5

SPT6

SPT7

SPT8

SPT9

SPT10

SPT11

Well graded SAND with gravel, loose, light brown, moist, subangular to angular, gravel up to 3/4" in diameter.

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

From 5 to 7.5', drill rig grinding on cobbles.

Below 7.5', brown, trace silt

Below 10', medium dense, gravel up to 1 1/2" in diameter.

Below 15', gravel up to 1/4" in diameter.

From 15 to 17.5', drill rig grinding on cobbles.

Below 17.5', gravel up to 1 3/4" in diameter.

Silty SAND with gravel, dense, light brown, moist, subangular to angular, gravel up to 1 1/2" in diameter.

Drill rig grinding at 24'

Below 25', slightly more moist, gravel up to 3/4" in diameter.

Below 35', gravel up to 1 1/4" in diameter.

5.0

20.0

40.0

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 48° 11' 55.01" (48.198615°)

LONGITUDE (DEGREES): W -121° 22' 39.41" (-121.377614°)

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: 56.5'

LIQUID LIMIT

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

2700 MP 6.9

0.0

4.0

8.0

12.0

16.0

20.0

24.0

28.0

32.0

36.0

40.0

MP 6.9, Stake had been pulled out, hole drilled 12' back from edge of failure and 5' from edge of road on inside.

NOTES:

BORING B17-09

COMPANY:

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Geotek Alaska LOGGER: N. Jenks

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

7/2/2017

S A

M P

LE

R

7/2/2017

STATION, OFFSET:

PLASTIC LIMIT

15-16-15 (16" = 89%)

15-25-34 (12" = 67%)

14-12-15 (14" = 78%)

12-16-16 (16" = 89%)

SPT12

SPT13

SPT14

SPT15

Well graded SAND with silt and gravel, dense, brown, moist, subangular, gravel up to 1" in diameter.

Below 45', very dense, subangular to angular.

Well graded SAND with gravel, medium dense, brown, moist, subangular to angular, gravel up to 3/4" in diameter.

Bottom of Boring at 56.5'

No groundwater encountered.

50.0

56.5

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 48° 11' 55.01" (48.198615°)

LONGITUDE (DEGREES): W -121° 22' 39.41" (-121.377614°)

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: 56.5'

LIQUID LIMIT

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

2700 MP 6.9

40.0

44.0

48.0

52.0

56.0

60.0

64.0

68.0

72.0

76.0

80.0

MP 6.9, Stake had been pulled out, hole drilled 12' back from edge of failure and 5' from edge of road on inside.

NOTES:

BORING B17-09

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Geotek Alaska LOGGER: N. Jenks

Sunny

DATE STARTED: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

7/2/2017

S A

M P

LE

R

7/2/2017

STATION, OFFSET:

PLASTIC LIMIT

15-60/3.5" (9" = 95%)

30-60/4" (10" = 100%)

23-50/2.5" (8" = 94%)

22-50/0.5" (6" = 93%)

50/0.5" (1" = 208%)

50/3" (3" = 100%)

50/2" (1" = 69%)

50/1.5" (2" = 128%)

SPT1

SPT2

SPT3

SPT4

SPT5

SPT6

SPT7

SPT8

Well graded SAND with silt and gravel, very dense, brown to gray, moist, angular, gravel up to 1 1/4" in diameter.

Top 5" sampler: brown silt, gravel.

Lower 4" sampler: gray silty rock.

PHYLLITE, dark gray to brown, highly weathered, very weak to weak (R1 to R2), platy foliation are 40 to 55 degrees from assumed horizontal. Residual soil is Silty SAND with gravel, very dense, gray, moist to dry, angular, gravel up to 1" in diameter.

Below 10', occasional drill rig grinding still but still mostly smooth drilling action.

At 12.5', rock fragments of phyllite, fragments are elongate and platy in shape.

Below 13', drill rig grinding, slower drilling.

From 20 to 25', steady drill rig grinding, a little slower drilling, slighty harder from 24 to 25'.

4.0

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 48° 21' 4.66" (48.351294°)

LONGITUDE (DEGREES): W -121° 37' 28.41" (-121.624559°)

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: 42'

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 40', NQ Core below 40'.

2800 MP 5.3

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

20.0

22.5

25.0

MP 5.3, Boring located 2' back on alignment from staked location, 18' from main scarp and 6' from secondary scarp.

NOTES:

BORING B17-10

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Geotek Alaska LOGGER: N. Jenks

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

7/3/2017

S A

M P

LE

R

7/3/2017

STATION, OFFSET:

Rec. = 88%

RQD = 0%

50/2.5" (2" = 79%)

50/0.5" (1" = 208%)

50/0.5" (1" = 208%)

50/1" (1" = 83%)

SPT9

SPT10

SPT11

SPT12

R1

At 25', a few slightly larger rock fragments.

Below 25', hard, slow drilling with drill rig grinding.

At 30', more silt, very little gravel.

From 30 to 35', cuttings consist of sandy silt, or silty sand, and little gravel. Slow hard drilling.

Sample collected.

From 35 to 40', hard slow drilling. Pounded on inner drill steel at 36' with hammer to see if it could break up rock to keep augering (repeated at 37 and 38'). Easier drilling from

39.5 to 40'.

At 40', rock fragments. Appear to be phyllite, fragments are elongate and platy in shape.

Bottom of Boring at 42.0'

No groundwater encountered.

42.0

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

LATITUDE (DEGREES): N 48° 21' 4.66" (48.351294°)

LONGITUDE (DEGREES): W -121° 37' 28.41" (-121.624559°)

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: 42'

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 40', NQ Core below 40'.

2800 MP 5.3

25.0

27.5

30.0

32.5

35.0

37.5

40.0

42.5

45.0

47.5

50.0

MP 5.3, Boring located 2' back on alignment from staked location, 18' from main scarp and 6' from secondary scarp.

NOTES:

BORING B17-10

COMPANY:

F ile

: C :\M

Y F

IL

E

S \P

W _P

R O

D U

C T

IO

N

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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

: 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

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LT

S \F

H W

A

LI

B R

A R

Y nt ed

: 1 /9

/2

Geotek Alaska LOGGER: N. Jenks

Sunny

DATE STARTED: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

7/3/2017

S A

M P

LE

R

7/3/2017

STATION, OFFSET: