Geotechnical Report Shotgun Cove Road Improvements

Whittier, Alaska

NOVEMBER 2004

Submitted To: Arctic Slope Consulting Group

3900 C Street. Suite 501 Anchorage, Alaska 99503

By: Shannon & Wilson, Inc.

5430 Fairbanks Street, Suite 3 Anchorage, Alaska 99518

Phone: 907-561-2120 Fax: 907-561-4483

E-mail: wsb@shanwil.com

Project Number: 32-1-01657

SHOTGUN COVE ROAD STATION 98+00 TO 104+00

PAGES HAVE BEEN REMOVED FROM APPENDICES A, B, AND C BEARING DATA FROM EXPLORATION BEYOND THE PROJECT LIMITS.

(5/12/2015)

SHANNON & WILSON, INC.

APPENDIX A

PLAN AND PROFILE SHEETS

TABLE OF CONTENTS

Section A.1 Subsurface Investigation

A 1.1 Geotechnical Borings A 1.1.1 Soil Sampling A 1.1.2 Rock Sampling·

A2 Surface Reconnaissance

LIST OF FIGURES

Page A-1 A-1 A-2 A-2 A-3

Figure A-1 Figures A-2 through A-10

Plan and Profile Sheet Legend Plan and Profile Sheets

32-1-01657

SHANNON & WILSON, INC.

The Shotgun Cove Road Improvement Project is located along approximately 2 miles of Shotgun

Cove Road extending from the east end of Whittier. The purpose of the explorations described

below is to provide a banlc of subsurface information that can be used in the design/build phase

of tllis project. The information included herein should be considered a starting point as

adjustments from the currently proposed alignment later in the project life or other data needs

may require additional explorations along the project alignment.

A.l Subsurface Investigations

Subsurface explorations consisted of advancing and sampling 33 soil borings designated Borings

B-01 through B-32 to evaluate subsurface conditions. Borings B-06 through B-08 and Borings

B-21 and B-23 were advanced at bridge abutment locations. Borings B-26 through B-29 vvere

advanced along Salmon Run Road and Borings B-30 through B-32 were advanced along

Blackstone Road. The remaining borings were generally advanced every 400 to 500 feet along

the existing alignment of Shotgun Cove Road. The approximate locations of these explorations

are included on the plan and profile sheets in Appendix A. Logs of the borings are included in

Appendix B.

A.l.l Geotechnical Borings

Borings were conducted at many locations along the road alignment for several purposes.

Borings located at the bridge abutments were drilled to bedrock and were advanced at least 7 feet

into bedrock so that bedrock could be confirmed and classified. Borings positioned near boggy

areas were intended to evaluate the peat thickness and to classify the nature of the soils beneath

the surface organics. The remaining borings were advanced through the road prism and/or

embankment fill areas to auger refusaL

Drilling services for this project were provided by Discovery Drilling, of Anchorage, Alaska,

using a track mounted CME 55-drill rig. Through soils, borings were advanced with 3-1 I 4- inch

inner diameter (ID), continuous-flight, hollow-stem augers. In the borings at bridge abutment

locations, rock coring was used to sample and confirm bedrock. This was accomplished using an

A W-34 (34 mm I 1.3 inch inner diameter) core barrel.

An experienced geologist from Shannon & Wilson was present continuously during the field

work to locate the borings, observe drilling operations, recover soil samples, and log the

GEOTECHNICAL REPORT Shotgun Cove Road Improvements, Whittier, Alaska ASCG

November 2004 Page A-1

32-1-01657

SHANNON & WILSON, INC.

subsurface conditions encountered in each boring. At the completion of the borings, they were

backfilled using the cuttings removed during the drilling activity.

A.l.l.l Soil Sampling

As a boring was advanced through soil, sampling was generally accomplished at 5-foot depth

intervals using Standard Penetration Test procedures. With this method, a 2-inch outside

diameter (OD) split-spoon sampler is advanced 18 or 24 inches into the undisturbed soil at the

bottom of the boring, with blows ·of a 140-pound surface hammer falling 30 inches on the drill

rods. The number of blows required to produce the finall2 inches of an 18-inch penetration of

the hammer or the middle 12 inches of a 24-inch penetration, defined as the Standard Penetration

Resistance, was recorded for each sample. When hard or very dense soils, coarse gravel or

bedrock were encountered, the sampler often could not be driven the full 18 inches, or in some

cases even 12 inches. The blow counts, which are noted on the logs, are uncorrected values and

provide a means of evaluating the relative density (compactness) or consistency (stiffness) of

cohesionless or cohesive soils, respectively. When a full 18 inches penetration was not

achieved, blows and the penetration achieved are recorded on the logs.

A.l.l.2 Rock Sampling

Where applicable, bedrock was confirmed by using a 5 foot long BQ core barrel with a diamond

impregnated bit and wire line coring methods. Continuous 1-5/8-inch diameter core extracted

from each 5 foot or less run was classified in the field by our geologist, who also placed the core

in two-foot long core boxes. The depths of the top and bottom of each run, percent recovery, and

other drilling notes were recorded. Bedrock was assumed if at least 5 feet of continuous,

moderate quality return was achieved. Recovered cores were delivered to our Anchorage

laboratory for further classification, testing and photographing. Photographs of the core samples

collected during our explorations are presented in Appendix B on the Rock Core Logs.

A.2 Surface Reconnaissance

Surface reconnaissance was performed along the project alignment to characterize ground

conditions that may be encountered during the constmction of the road improvements. This

effort included generalized surveys of exposed rock cuts along Shotgun Cove Road.

GEOTECHNICAL REPORT Shotgun Cove Road Improvements, Whittier, Alaska ASCG

November 2004 Page A-2

32-l-01657

SHANNON & WILSON, INC.

At the major rock outcrops observed along the existing roadway, generalized bedrock mapping

was performed. At each mapping site, information regarding the exposed rock type(s), major

joint set(s) orientation, and average joint spacing were recorded. Photographs were also taken of

each of these sites. Information is presented on the plan and profile sheets in Appendix A.

GEOTECHNICAL REPORT Shotgun Cove Road Improvements, Whittier, Alaska ASCG

November 2004 Pasze A-3

32-1 .:-o 1657

Rock Core Log for Boring B-21

1.5

3.5

5.5

7.5

9.5

11.5

80%Recovery

100%Recovery

100%Recovery

RQD=21%

RQD=28%

RQD=22%

Gray, phyllite (metamorphosed shale) with weak foliation.Highly weathered (incompetant) section.

Aver

age

Joint

Spa

cing

Dom

inant

Joint

Ang

lesBe

dding

Ang

lesFo

liatio

n Ang

les

Relat

ive H

ardn

ess

Effe

rves

cenc

e

Joint

Sm

ooth

ness

Joint

Infill

ing

Degr

ee o

f

Wea

ther

ing

CORERUN

ftbgs DESCRIPTION

N/A

N/A

N/A

mo

d

none

roug

h

none

high

S2

S3

S 4

1.5

8.9

11.5

Gray, phyllite (metamorphosed shale) with weak foliation.Moderate to highly weathered. Zone of quartz strands and

cross cutting quartz stringers from 9.2 - 10.2 ft. bgs.

4 -

5 in

ches

65 d

egre

es

60 -

90

degr

ees

mod

erat

e

none

roug

h

none

none

to

low

N/A

N/A

*Note:

1. Visual classification of smoothness of joint surfaces (smooth, moderately smooth, moderately rough, rough)2. Indicates effort required to scratch core surface with steel stylus (easy, moderate, hard)3. Visual classification of apparent weathering of core (none, low, moderate, high)

Shotgun Cove Road Improvements

Rock Core Log, Boring B-21

Whittier, Alaska

November 2004

Fig. B-39

32-1-01657

SHANNON & WILSON, INC.Geotechnical & Environmental Consultants

1 2

3

2.6

3.4

Gray, phyllite (metamorphosed shale) with weak foliation.Highly competant section with no apparent bedding and

very little to no quartz stringers.

Gray, phyllite (metamorphosed shale) with weak foliation.Porous quartz strand that cross cuts foliation from 3.4 - 6.4 ft.bgs. Thin quartz stringers that cross cut foliation throughout

section and asymmetrical folding from 7.8 - 8.9 ft. bgs.

4 in

40 d

eg

N/A

1@

10 d

eg

mo

dsm

ooth

none

mo

d

none

none

to lo

w

<1/

2 in

ch

N/A

N/A

20 -

50

degr

ees

roug

h

none

mod

erat

e

none

high

Rock Core Log for Boring B-23

2.2

4.2

6.2

8.2

10.2

12.2

81%Recovery

100%Recovery

91%Recovery

RQD=12%

RQD=39%

RQD=51%

Gray, graphitic schist (metamorphosed shale) withlow to moderate foliation. Highly sheared zone

and quartz stringers that cross cut foliation.

Aver

age

Joint

Spa

cing

Dom

inant

Joint

Ang

lesBe

dding

Ang

lesFo

liatio

n Ang

les

Relat

ive H

ardn

ess

Effe

rves

cenc

e

Joint

Sm

ooth

ness

Joint

Infill

ing

Degr

ee o

f

Wea

ther

ing

CORERUN

ftbgs DESCRIPTION

<1 in

ch

75 d

egre

es

80 d

egre

es

mod

erat

e

none

smoo

th o

vera

ll,

roug

h @

qua

rtz

cont

acts

none

mod

erat

e to

hig

h

S3

S4

S5

2.2

4.5

12.2

Gray, graphitic schist (metamorphosed shale) withlow to moderate foliation. Quartz stringers that crosscut foliation from 7.8 - 9.3 ft. bgs and a moderately

sheared zone from 7.2 - 7.5 ft. bgs. 4 in

ches

80 d

egre

es

80 d

egre

es

mod

erat

e

none

smoo

th

none

low

70-8

0 de

gree

s80

deg

rees

*Note:

1. Visual classification of smoothness of joint surfaces (smooth, moderately smooth, moderately rough, rough)2. Indicates effort required to scratch core surface with steel stylus (easy, moderate, hard)3. Visual classification of apparent weathering of core (none, low, moderate, high)

Shotgun Cove Road Improvements

Rock Core Log, Boring B-23

Whittier, Alaska

November 2004

Fig. B-40

32-1-01657

SHANNON & WILSON, INC.Geotechnical & Environmental Consultants

1 2

3