earth + water Aspect Consulting, LLC 26, 2011 Aspect … · classified in general accordance with the ASTM D-2488, “Standard Practice for Description and Identification of Soils”

MEMORANDUM October 26, 2011 Project No.: 060036-003-05

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field by measuring from existing Site features. Both borings were located on the east side of the roadway within the gravel shoulder.

Borings EB-12 and EB-13 were advanced to a maximum depth of 51.5 feet and 45.83 feet below the ground surface, respectively. The borings were drilled using a modified B-53 track-mounted hollow-stem auger drill rig equipped with an 8-inch-diameter auger. The drill was operated by Davies Drilling under the direction of Aspect. Split spoon (1 3/8-inch inner diameter) samples were obtained from the borings in general accordance with Standard Penetration Test Procedures (American Society for Testing and Materials [ASTM D-1586]), at 2.5- and 5-foot intervals. The split spoon sampler is driven 18 inches into the soil by a 140-pound hammer falling 30-inches. The number of blows required to drive the sampler are counted for each 6 inches of penetration. The blow count for the first 6 inches of penetration is discarded, and the remaining blow counts are summed to produce the Standard Penetration Resistance (N).

Logs of the borings indicating the type of soils encountered are attached as Appendix A. The depths indicated on the logs where conditions changed may represent gradational variations between soil types. Changes logged between sample intervals in our borings were interpreted. Soils were classified in general accordance with the ASTM D-2488, “Standard Practice for Description and Identification of Soils” (Visual and Manual Procedure).

Stratigraphy As shown on the attached exploration logs, our explorations encountered active landslide debris overlying relatively undisturbed glaciolacustrine. More detailed descriptions of the soils encountered at the Site are provided below:

Fill Road embankment fill was encountered in both borings at the ground surface to a depth of 5 feet below the existing ground surface. The presence of fill was inferred to be the remnants of past grading operations in the area. Typically the roadway fill consisted of loose to medium dense, moist, dark brown, silty, sandy GRAVEL (GM) with scattered asphalt debris.

Landslide Debris The loose to medium dense sand was encountered in both borings underlying the roadway fill and extended to depths of 45.5 and 30.5 feet below the existing ground surface in EB-12 and EB-13, respectively. This unit was interpreted as active landslide debris derived from previously intact, Vashon advance outwash sediments, located upslope of the Site. The landslide debris encountered in the borings is the result of ongoing vertical and horizontal displacement of the soil. The landslide debris typically consisted of loose to medium dense, moist to wet, brown to gray, poorly graded SAND (SP) with varying amounts of silt and gravel and scattered organics debris. Groundwater levels at the time of drilling were encountered in the landslide debris unit at depths of 34.0 feet and 22.5 feet below the existing ground surface in EB-12 and EB-13, respectively.

Vashon Glaciolacustrine Underlying the landslide debris were glaciolacustrine soils. Both borings were terminated in relatively undisturbed and intact glaciolacustrine clay. A disturbed zone of the lacustrine unit ranging from 4.5 to 14.5 feet in thickness was present immediately underlying the landslide debris in both


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borings. This disturbed zone was interpreted as prehistoric landslide debris consisting of highly fractured silty CLAY (CL) with interbedded zones of fine sand. Underlying the disturbed zone, were relatively intact glaciolacustrine soils consisting of hard, moist, blue-gray, silty CLAY (CL) with thin laminae visible and an undisturbed texture.

Based on the presence of groundwater in the overlying landslide debris, the undisturbed glaciolacustrine soils encountered at depth in the borings are interpreted as the base of the active landslide area.

Hydrology Groundwater was encountered in EB-12 at a depth of 34.0 feet and in EB-13 at a depth of 22.5 feet below the existing ground surface at the time of drilling. These depths correspond to elevations of approximately 57 feet and 63.5 feet, respectively. We observed groundwater seepage exposed on the slope, upslope from the right-of-way. The seepage was located above a prominent clay outcrop that represents the contact between the in-place advance outwash sand (above) and the in-place glaciolacustrine (below). The contact represents the undisturbed stratigraphic column outside the active landslide area. The seepage flow rate observed was estimated between 1 and 5 gallons per minute.

Monitoring Station Installations and Details Following completion of the borings, slope inclinometer casings were installed to approximately the bottom of each borehole. The inclinometer casing consisted of a 2.75-inch-outside diameter ABS pipe with a pair of orthogonal slots, or grooves, that permit a calibrated instrument probe to be lowered to the bottom of the pipe. When the ground surrounding the inclinometer casing moves, the casing will distort within the zone of movement allowing the instrument probe to record the deflections and distortion.

A vibrating-wire piezometer (VWP) was also secured to each inclinometer casing to measure groundwater levels. The piezometer (including the porous stone) was saturated and checked for proper function prior to being installed. During installation of the inclinometer casing, the piezometer was attached in an inverted position to the casing at a pre-determined location to be installed below the observed and historic groundwater level. The piezometer and cable were secured to the inclinometer casing using fiberglass tape.

Following installation of the inclinometer casing and the piezometer, the casing was tightly capped, and the annular space between the casing and borehole wall was filled by pumping a cement-bentonite grout into the borehole. Following the grouting process, a single-channel datalogger was connected to the piezometer to record water levels every 12 hours. A metal monument with a flush-mount lid was installed to protect the top of the inclinometer and datalogger.

Monitoring Plan Aspect proposes monitoring these new installations monthly until January 2012. At that time, a summary of data will be prepared and submitted to the County. Changes in the monitoring schedule will be discussed relative to the current weather issues and any changes in the reporting systems for water elevation readings will be discussed.


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References Aspect Consulting, LLC (Aspect), 2006, Subsurface Exploration, Geologic Hazard, And

Geotechnical Engineering Report, Washington Boulevard Landslide Kingston, Washington, prepared for Kitsap County Department of Public Works. March 30, 2006.

Limitations Work for this project was performed and this memorandum prepared in accordance with generally accepted professional practices for the nature and conditions of work completed in the same or similar localities, at the time the work was performed. It is intended for the exclusive use of Kitsap County Department of Public Works for specific application to the referenced Site. This memorandum does not represent a legal opinion. No other warranty, expressed or implied, is made.

Attachments Figure 1 – Site and Exploration Plan – New Explorations and Monitoring Stations Appendix A – Exploration Logs

W:\_GEOTECH\060036 Washington Boulevard Landslide\Deliverables\New Monitoring Stations Memo\Installation Memo.docx

APPENDIX A

Exploration Logs

Classifications of soils in this report are based on visual field and/or laboratory observations, which include density/consistency, moisture condition, grain size, and plasticity estimates and should not be construed to imply field or laboratory testing unless presented herein. Visual-manual and/or laboratory classification methods of ASTM D-2487 and D-2488 were used as an identification guide for the Unified Soil Classification System.

Terms Describing Relative Density and Consistency

Estimated Percentage

Symbols

Moisture ContentPercentageby Weight

SamplerType

Sampler TypeDescription

Blows/6" orportion of 6"

Component DefinitionsSize Range and Sieve Number

Larger than 12"Descriptive Term

Smaller than No. 200 (0.075 mm)

3" to 12"

Coarse-Grained Soils

Fine-Grained Soils

DensityVery LooseLooseMedium DenseDenseVery Dense

SPT blows/foot0 to 44 to 1010 to 3030 to 50>50

(2)

0 to 22 to 44 to 88 to 1515 to 30>30

ConsistencyVery SoftSoftMedium StiffStiffVery StiffHard

SPT blows/foot(2)

2.0" OD Split-Spoon Sampler(SPT) Continuous Push

Non-Standard SamplerBulk sample

3.0" OD Thin-Wall Tube Sampler (including Shelby tube)

Grab Sample

Portion not recovered

(1)

ATD = At time of drillingStatic water level (date)

Percentage by dry weight(SPT) Standard Penetration Test (ASTM D-1586)In General Accordance withStandard Practice for Description and Identification of Soils (ASTM D-2488)

Test Symbols

Depth of groundwater(4)

(1)

(2)

(3)

Cement grout surface seal

Groutseal

End cap

Filter pack with blank casing section

Boulders

Silt and Clay

Gravel Coarse Gravel Fine Gravel

Cobbles

Sand Coarse Sand Medium Sand Fine Sand

Dry - Absence of moisture, dusty, dry to the touch

Slightly Moist - Perceptible moisture

Moist - Damp but no visible water

Very Moist - Water visible but not free draining

Wet - Visible free water, usually from below water table

Hig

hly

Org

anic

S

oils

Fin

e-G

rain

ed S

oils

- 5

0%

or

Mor

e P

asse

s N

o. 2

00 S

ieve

(1)

Coa

rse-

Gra

ined

Soi

ls -

Mor

e th

an 5

0%

Ret

aine

d on

No.

200

Sie

ve

Gra

vels

- M

ore

than

50%

o

f Coa

rse

Fra

ctio

n R

etai

ned

on N

o. 4

Sie

ve15

% F

ines

5% F

ines

San

ds -

50%

o

r M

ore

of C

oars

e Fr

actio

n P

asse

s N

o. 4

Sie

veS

ilts

and

Cla

ysLi

quid

Lim

it Le

ss th

an 5

0S

ilts

and

Cla

ysLi

quid

Lim

it 50

or

Mor

e

(5) Combined USCS symbols used for fines between 5% and 15% as estimated in General Accordance with Standard Practice for Description and Identification of Soils (ASTM D-2488)

(1)

(1)

15%

Fin

es5%

Fin

es(5

)(5

)(5

)(5

)

FC = Fines ContentG = Grain SizeM = Moisture Content A = Atterberg Limits C = ConsolidationDD = Dry DensityK = PermeabilityStr = Shear StrengthEnv = EnvironmentalPiD = Photoionization

No. 4 (4.75 mm) to No. 10 (2.00 mm)No. 10 (2.00 mm) to No. 40 (0.425 mm)No. 40 (0.425 mm) to No. 200 (0.075 mm)

3" to No. 4 (4.75 mm)3" to 3/4"3/4" to No. 4 (4.75 mm)

No. 4 (4.75 mm) to No. 200 (0.075 mm)

Well-graded gravel and gravel with sand, little to no fines

Poorly-graded gravel and gravel with sand, little to no fines

Silty gravel and silty gravel with sand

Clayey gravel and clayey gravel with sand

Well-graded sand and sand with gravel, little to no fines

Poorly-graded sand and sand with gravel, little to no fines

Silty sand and silty sand with gravel

Clayey sand and clayey sand with gravel

Silt, sandy silt, gravelly silt, silt with sand or gravel

Clay of low to medium plasticity; silty, sandy, or gravelly clay, lean clay

Organic clay or silt of low plasticity

Elastic silt, clayey silt, silt with micaceous or diato-maceous fine sand or silt

Clay of high plasticity, sandy or gravelly clay, fat clay with sand or gravel

Organic clay or silt of medium to high plasticity

Peat, muck and other highly organic soils

GW

GP

GM

GC

SW

SP

SM

SC

ML

CL

OL

MH

CH

OH

PT

Trace

Slightly (sandy, silty,clayey, gravelly)Sandy, silty, clayey,gravelly)Very (sandy, silty,clayey, gravelly)

Modifier<5

5 to 15

15 to 30

30 to 49

Screened casing or Hydrotip with filter pack

Bentonitechips

FIGURE NO.

PROJECT NO.DATE:

REVISED BY:

DRAWN BY:

DESIGNED BY:

www.aspectconsulting.com

earth + water Exploration Log Key

A-1

Q:\_

AC

AD

Sta

ndar

ds\S

tand

ard

Det

ails

\Exp

lora

tion

Log

Key

A1.

dwg

Detector

Grouted Transducer

BGS = below ground surface

ROAD FILL

Medium dense, slightly moist, brown to black,sandy GRAVEL (GM); poorly graded fine sand,slightly silty.

ACTIVE SLIDE DEBRIS

Loose, slightly moist, brown SAND (SP); poorlygraded fine to medium sand, slightly gravelly, fineto coarse, subrounded gravel, trace silt.

Becomes moist, oxidation and rust staining,scattered organic debris at 10 feet.

Loose, moist, light brown, SAND (SP); poorlygraded fine to medium sand, scattered finegravel.

5710

3510

322

222

S-1

S-2

S-3

S-4

Data logger (S/N

37414) and steel flush

monument at ground

surface

Installed 2-3/4" dia.

slope indicator casing

to 48.33' bgs.

Casing grouted in

place with mix

containing 94 lb

Portland cement, 25 lb

bentonite gel, 30

gallons water.

Grout take estimated at

150% of the theoretical

volume.

Ground Surface Elev

30 40

EB-12Washington Boulevard Landslide

Project Number Sheet

Figure No.

Depth to Water (ft BGS)

5

10

15

0

9/27/2011-9/28/2011

_GE

OT

EC

H B

OR

ING

LO

G W

AS

HIN

GT

ON

BO

ULE

VA

RD

LA

ND

SLI

DE

.GP

J O

ctob

er 2

6, 2

011

Logged by:

Start/Finish Date

A- 2

Davies Drilling / Modified B-53 Track Rig

MR: Mud Rotary

Driller/Equipment:

10 20

Blows/

Approved by:

HSA / Cathead / 140# / 30" Drop

Project Name:

Location:

1 of 3

Boring Log

Borehole Completion MaterialType

SampleType/ID

JLP

Drilling Method:

HSA: Hollow Stem Auger

Washington Boulevard NE, Kingston, WA

5

10

15

91

Depth /Elevation

(feet)

Tests

No Recovery

50

Sampler Type:

Depth(ft)

Drilling Method/Hammer:

Description

AJH

Standard Penetration Test(ASTM D1586)

Boring Number

060036

90

85

80

75

N-valueWater Content %

34.0

6"

Loose, moist, light brown, SAND (SP); poorlygraded fine to medium sand, scattered finegravel.

Prominent zone of gravel at 22.5 feet based ondrill action.

Loose to medium dense, moist, brown, SAND(SP-SM); poorly graded fine sand, slightly silty,trace fine gravel.

VASHON GLACIOLACUSTRINE

Stiff, slightly moist, gray, CLAY (CL); highlyfractured, intermixed laminae of loose, lightbrown SAND (SP).Medium dense, wet, gray, SAND (SP); poorlygraded fine to medium sand, trace gravel and silt.

Interbedded with stiff, very moist, blue-gray, siltyCLAY (CL); low plasticity, highly fractured,disturbed texture.

424

346

8109

61219

S-5

S-6

S-7

S-8

S-9

Ground Surface Elev

30 40



Figure No.


25

30

35

0

9/27/2011-9/28/2011

_GE

OT

EC

H B

OR

ING

LO

G W

AS

HIN

GT

ON

BO

ULE

VA

RD

LA

ND

SLI

DE

.GP

J O

ctob

er 2

6, 2

011

Logged by:

Start/Finish Date

A- 2


MR: Mud Rotary

Driller/Equipment:

10 20

Blows/

Approved by:


Project Name:

Location:

2 of 3

Boring Log


SampleType/ID

JLP

Drilling Method:



25

30

35

91

Depth /Elevation

(feet)

Tests

No Recovery

50

Sampler Type:

Depth(ft)


Description

AJH


Boring Number

060036

70

65

60

55


34.0

6"

Medium dense, wet, gray, SAND (SP); poorlygraded fine to medium sand, trace gravel and silt.

Interbedded with stiff, very moist, blue-gray, siltyCLAY (CL); low plasticity, highly fractured,disturbed texture.

Hard, moist, gray, CLAY (CL); low to mediumplasticity, slightly silty, frequent lighter coloredlaminae, scattered fine sand laminae, relativelyundisturbed.

Bottom of boring at 51.5 feet.

71110

71716

111018

S-10

S-11

S-12

Vibrating wire piezo

(S/N 11-5477) installed

at 45.5' bgs.

Ground Surface Elev

30 40



Figure No.


45

50

55

0

9/27/2011-9/28/2011

_GE

OT

EC

H B

OR

ING

LO

G W

AS

HIN

GT

ON

BO

ULE

VA

RD

LA

ND

SLI

DE

.GP

J O

ctob

er 2

6, 2

011

Logged by:

Start/Finish Date

A- 2


MR: Mud Rotary

Driller/Equipment:

10 20

Blows/

Approved by:


Project Name:

Location:

3 of 3

Boring Log


SampleType/ID

JLP

Drilling Method:



45

50

55

91

Depth /Elevation

(feet)

Tests

No Recovery

50

Sampler Type:

Depth(ft)


Description

AJH


Boring Number

060036

50

45

40

35


34.0

6"

ROAD FILL

Loose, moist, dark brown, silty, sandy GRAVEL(GM); poorly graded fine to coarse, subroundedto subangular gravel, poorly graded fine tomedium sand, scattered asphalt debris.

ACTIVE SLIDE DEBRIS

Loose, moist, brown SAND (SP); poorly gradedfine to medium sand, trace gravel and silt.

Becomes medium dense, brown to light gray withslight rust staining/oxidation at 10 feet.

Becomes loose at 15 feet.

641

644

487

322

S-1

S-2

S-3

S-4

Data logger (S/N

37415) and steel flush

monument at ground

surface

Installed 2-3/4" dia.

slope indicator casing

to 43.04' bgs.

Casing grouted in

place with mix

containing 94 lb

Portland cement, 25 lb

bentonite gel, 30

gallons water.

Grout take estimated at

110% of the theoretical

volume.

Ground Surface Elev

30 40



Figure No.


5

10

15

0

9/28/2011-9/30/2011

_GE

OT

EC

H B

OR

ING

LO

G W

AS

HIN

GT

ON

BO

ULE

VA

RD

LA

ND

SLI

DE

.GP

J O

ctob

er 2

6, 2

011

Logged by:

Start/Finish Date

A- 3


MR: Mud Rotary

Driller/Equipment:

10 20

Blows/

Approved by:


Project Name:

Location:

1 of 3

Boring Log


SampleType/ID

JLP

Drilling Method:



5

10

15

86

Depth /Elevation

(feet)

Tests

No Recovery

50

Sampler Type:

Depth(ft)


Description

AJH


Boring Number

060036

85

80

75

70


22.5

6"

ACTIVE SLIDE DEBRIS

Loose, moist, brown SAND (SP); poorly gradedfine to medium sand, trace gravel and silt.Becomes very moist to wet at 20 feet.

Becomes very loose at 25 feet.

VASHON GLACIOLACUSTRINE

Stiff, very moist, blue-gray, silty CLAY (CL); lowplasticity, high angle fractures, disturbed texture.

Intermixed zones of medium dense, wet, graySAND (SP); poorly graded fine to medium sandwith scattered gravel.

Hard, moist, blue-gray, silty CLAY (CL); lowplasticity, thin laminae, relatively undisturbed.

123

102

3410

142142

S-5

S-6

S-7

S-8

Vibrating wire piezo

(S/N 11-5478) installed

at 38.04' bgs.

Ground Surface Elev

30 40



Figure No.


25

30

35

0

9/28/2011-9/30/2011

_GE

OT

EC

H B

OR

ING

LO

G W

AS

HIN

GT

ON

BO

ULE

VA

RD

LA

ND

SLI

DE

.GP

J O

ctob

er 2

6, 2

011

Logged by:

Start/Finish Date

A- 3


MR: Mud Rotary

Driller/Equipment:

10 20

Blows/

Approved by:


Project Name:

Location:

2 of 3

Boring Log


SampleType/ID

JLP

Drilling Method:



25

30

35

86

Depth /Elevation

(feet)

Tests

No Recovery

50

Sampler Type:

Depth(ft)


Description

AJH


Boring Number

060036

65

60

55

50


22.5

6"

50+

Hard, moist, blue-gray, silty CLAY (CL); lowplasticity, thin laminae, relatively undisturbed.

Bottom of boring at 45.83 feet.

2650/3.5"

4450/4"

S-9

S-10

Ground Surface Elev

30 40



Figure No.


45

50

55

0

9/28/2011-9/30/2011

_GE

OT

EC

H B

OR

ING

LO

G W

AS

HIN

GT

ON

BO

ULE

VA

RD

LA

ND

SLI

DE

.GP

J O

ctob

er 2

6, 2

011

Logged by:

Start/Finish Date

A- 3


MR: Mud Rotary

Driller/Equipment:

10 20

Blows/

Approved by:


Project Name:

Location:

3 of 3

Boring Log


SampleType/ID

JLP

Drilling Method:



45

50

55

86

Depth /Elevation

(feet)

Tests

No Recovery

50

Sampler Type:

Depth(ft)


Description

AJH


Boring Number

060036

45

40

35

30


22.5

6"

50+

50+

Documents

earth + water Aspect Consulting, LLC 26, 2011 Aspect … · classified in general accordance with the ASTM D-2488, “Standard Practice for Description and Identification of Soils”