C-2 Attachment 8 Geotechnical Memo.pdf

Perry Palmer, Project Manager October 30, 2020

DJ&A, P.C.

2000 Maple Street Missoula, MT 59808

Subject: USFS Kenai Lake Work Center Geotechnical Investigation

Dear Mr. Palmer, PND Engineers, lnc. (PND), on behalf of DJ&A, performed a geotechnical investigation on October 13, 2020 for the United States Forest Service (USFS)to characterize subsurface soil conditions along a proposed road section and to perform percolation tests at the USFS Kenai Lake Work Center located along the Seward Highway south of Moose Pass, Alaska. PND personnel used a backhoe to dig 9 test pits to a nominal depth of 9 feet below-ground-surface (bgs). Percolation testing was completed in 4 test pits and grab samples were collected at all test pits to characterize the subsurface soil conditions at the shallow depth. The geotechnical investigation was performed at locations identified during a field meeting held on September 25, 2020. Test Pit 1 corresponds to both the expansion of the administration building and the proposed access road. Test Pits 2, 3, and 4 are located along the proposed access road. Test Pit 6 was located at the proposed pole barn. Test Pits 7, 8, 9, and 10 are located in the proposed leach field area. Test Pit 5 was omitted in the field due to proximity to underground utilities. As-built locations are presented in Figure 1. The approximate latitude and longitude of the test pits are provided in Table 1 with horizontal datum NAD83 AKSP Zone 4.

Table 1. As-built Test Pit Locations Test Pit

ID Latitude* Longitude*

TP-1 60.40688°N 149.37457°W

TP-2 60.40703°N 149.37327°W

TP-3 60.40727°N 149.37307°W

TP-4 60.40663°N 149.37232°W

TP-6 60.40542°N 149.37013°W

TP-7 60.40528°N 149.37185°W

TP-8 60.40503°N 149.37103°W

TP-9 60.40488°N 149.37223°W

TP-10 60.40507°N 149.37168°W

*NAD83 AKSP Zone 4

October 2020 Kenai Lake Work Center Geotechnical Memo

Figure 1. Location of as-built test pits at the Kenai Lake Work Center

INVESTIGATION DESCRIPTION

Nine test pits were advanced using a Hitachi Zaxis 50-U Excavator to a nominal depth of 9 feet bgs. Pit depths were limited by arm length of the excavator. Grab samples were collected based on the soil strata observed in the test pits. Percolation testing procedure was based on the Falling Head Percolation Test Procedure in the Environmental Protection Agency Design Manual: Onsite Wastewater Treatment and Disposal Systems (EPA 625/1-80-012). Percolation testing occurred in four test pits: TP-7, -8, -9, and -10. The proposed drain field location for the new wastewater collection system is located in the southern portion of the Kenai Lake Work Center campus. A 2- to 4-foot bench was dug to provide access to the test pits for the percolation testing. Tests at 2 feet bgs were conducted in a silt with sand and gravel layer. Tests at 4 feet bgs were in a gravel with sand layer. The percolation test pipe measured 12-inches long with a 4-inch inner diameter. Perforations extended around the bottom 4-inches. The percolation testing pipe was buried roughly 6 inches in clean native well-graded gravel at the bottom of either the 2- or 4-foot bench. A 1-inch layer of gravel was placed inside the percolation testing pipe.

The water level inside the percolation testing pipe was maintained at a constant level during the presoak period.

The gravel and silt layers were presoaked for a 2-hour period based on the head drop. Percolation testing began following presoaking with readings taken every 1 minute in gravel and every 10 minutes in silt. Test continued until two successive water level drops did not vary by more than 1/16-inch following at least three measurements.

SITE CHARACTERIZATION

Grab samples obtained from the test pits were collected and sealed in freezer bags to maintain in-situ moisture content. The samples were then transported to PND’s Soil Material Laboratory in Anchorage for testing. All tests were performed to ASTM standards where applicable. A total of 41 lab tests were performed (Table 2). Lab characterizations included the following tests:

• Moisture Content/Classification (ASTM D4318)

• Description and Identification of Soils—Visual-Manual Procedure (ASTM D2488, ASTM D2487)

• Particle Size Analysis (ASTM D422)

• Fines Wash (ASTM D1140)

Table 2. Summary of Laboratory Tests

Test Type Quantity Moisture Content with Classification (ASTM D2487 / D2488 / D4318) 35

Gradation of Soils (ASTM D6913) 3 Fines Wash (ASTM D1140) 3

SOIL TYPE AND DESCRIPTION

Proposed Administration Building Expansion

Examination of TP-1 showed similar materials to TB-01, -02, and -03 in the DOWL report, “Final Subsurface Investigation, 2004.”

Proposed Access Road Section

Test Pits 1, 2, 3, and 4 are located along the proposed access road. Gradation tests were performed on three (3) representative soil samples in this area to determine the general gradation of gravel present at the proposed access road. The samples used for gradations include Sample No. 3 and No. 4 from TP-2, and Sample No. 3 from TP-4. These samples were chosen for testing because they best represent the overall trends observed in the gravel material present in the proposed access road area. Table 3 shows gravel, sand, and fines fraction of the gradations performed on the soil. D50 defines the particle size at the 50% fraction by mass. P10 describes the percent passing the #10 sieve (2-mm), a useful value in characterizing gravel behavior. Although the P10 particle size is classified as coarse sand, when present in sufficient quantity in the gravel matrix it behaves synergistically with the gravel particles to increase strength and stiffness in compacted fill materials, and maintain higher permeabilities.

Table 3. Representative Gradation Properties along the Proposed Roadway Section Test Pit

Sample No. Material Type

Soil Type Fractions (%) D50 (mm)

P10 (%) Gravel Sand Fines

TP-2 3 Well-Graded Gravelly Silty Sand (g(SW-SM)) 44 50 6 3.7 35

TP-2 4 Well-Graded Gravel with Sand (GWs) 66 29 5 12.8 21

TP-4 3 Well-Graded Sandy Gravel (sGW) 67 30 3 9.6 20

Along the road section, gravel particles were subrounded to subangular in texture, with the majority of the particles being subrounded. Cobbles were encountered in all test pits. The maximum cobble percentage occured in TP-4 with 20% by volume, beginning at 2 feet bgs. The remaining test pits had trace cobbles beginning at 5 feet bgs. Gravel ranged from 2.5 inches to cobble-sized (4 to 12 inches) at depths of 4 feet bgs. Higher fines contents were encountered at the ground surface, extending to a nominal depth of 1.5 feet bgs. A 1-foot thick clay layer was encountered in TP-3 at 4 feet bgs.

The gradation curves for the samples are shown in Attachment C.

Proposed Leach field

Four test pits, TP-7, -8, -9, and -10, were performed at the proposed leach field. The majority of the gravel particles were subrounded to subangular. Cobbles were present in all test pits. The maximum cobble percentage occurred in TP-7 with 20% by volume beginning at 4 feet bgs and the minimum occurred in TP-10 having 15% by volume beginning at 4 feet bgs. Boulders ranged between 1 and 2 feet across at TP-8 and -9 beginning at 4 feet bgs. Gravel ranged from 2 inches to cobble-sized beginning at 3 feet bgs. The fines content is at higher percentages at the ground surface extending to a nominal depth of 2 feet bgs.

Proposed Pole Barn

At the proposed pole barn (TP-6), the majority of the gravel particles were subrounded to subangular. Compacted fill material occupied the top 2.5 feet of the test pit. Cobbles were present beginning at 3 feet bgs. Gravel ranged from 2 inches to cobble-sized to depths of 9 feet bgs. The 2.5-foot thick sand layer beginning at 2.5 feet bgs was a coarse sand. The fines content is at higher percentages beginning at 2.5 feet to end-of-hole.

MOISTURE CONTENT

No groundwater was encountered during the field investigation. Table 4, Table 5, and Table 6 show a summary of the average representative moisture contents by depth for the proposed road section, leach field, and pole barn, respectively. This characterization is generalized to simply capture the general soil properties by depth. Moisture contents by sample and depth for the nine test pits are shown in the Summary of Sample Characteristics (Attachment B) and visually in Moisture Contents by Depth (Attachment D).

Table 4. Average Moisture Contents of the Proposed Access Road Section (TP-1, -2, -3, and -4) by Depth

Depth

(ft) Soil Type

M.C. Average

0 – 1.5 Organic Silt (OL) to Silt with Sand (MLs) with Peat (PT) 57.1

1.5 – 5.0 Well-Graded Sandy Gravel (sGW) with Silt and Clay 10.3

5.0 – 9.0 Well-Graded Sandy Gravel (sGW) 5.4

Table 5. Average Moisture Contents at the Proposed Leach Field (TP-7, -8, -9, and -10) by Depth

Depth

(ft) Soil Type

M.C. Average

0.0 – 2.0 Organic Silt (OL) to Silt with Sand (MLs) with Clay with Sand (CLs) to Peat (PT) 236.5

2.0 – 4.0 Poorly-Graded Sandy Gravel with Silt (s(GP-GM)) 14.5

4.0 – 9.0 Sandy Well-Graded Gravel (sGW) 5.1

Table 6. Average Moisture Contents at the Proposed Pole Barn (TP-6) by Depth

Depth

(ft) Soil Type

M.C. Average

0.0 – 2.0 Well-Graded Sandy Gravel (sGW) (Compacted Gravel Fill) 4.7

2.0 – 4.0 Well-Graded Gravelly Sand with Silt (g(SW-SM)) 4.6

4.0 – 9.0 Well-Graded Sandy Gravel with Silt (s(GW-GM)) 4.3

IDEALIZED SOIL PROFILES

Based on observations of the test pits and lab results, the soil at the proposed road section, leach field, and pole barn can be generally described as follows:

Along the proposed access road section (TP-1, -2, -3, and -4), an organic layer composed of organic silt, sand, and peat, approximately 1.5 feet thick, overlays 3.5 feet of varied soil layers consisting of primarily well-graded sandy gravel (sGW) with occasional silt with sand (MLs) and clay with sand (CLs) layers, with gravel particles mainly subrounded with occasional cobbles, overlaying well-graded sandy gravel (sGW), with gravel particles subrounded with 5-20% cobbles by volume.

At the proposed leach field (TP-7, -8, -9, and -10), an organic layer approximately 2.0 feet thick composed of varied layers of organic silt (OL), sand with silt (MLs), clay with sand (CLs) and peat (PT) overlays 2.0 feet of poorly-graded sandy gravel with silt (s(GP-GM)), with gravel particles mainly subrounded with occasional cobbles, overlaying well-graded sandy gravel (sGW), with gravel particles subrounded with 15-20% cobbles by volume and occasional 1-2 foot boulders.

At the proposed pole barn (TP-6), 2.0 feet of compacted gravel fill material composed of well-graded sandy gravel (sGW) with gravel particles mainly subrounded, overlays 2.0 feet of well-graded gravelly sand with silt (g(SW-SM)), with subrounded gravel particles with occasional cobbles, overlaying well-graded sandy gravel with silt (s(GW- GM)), subrounded to sub angular gravel particles subrounded with occasional cobbles.

Detailed soil characterizations for each test pit are provided in Attachment A: Test Pit Logs.

PERCOLATION TEST

Figure 2 is a profile view of the percolation pipe buried 6 inches at 4 feet bgs at TP-7. Percolation tests at TP-8 and TP-9 were performed in the silt layer present 2 feet bgs and tests at TP-7 and TP-10 were performed in the gravel layer present 4-foot bgs. Percolation rates differed significantly between the silt and gravel layers. The soil types and layers were comparable throughout TP7-10 and the percolation results should be considered applicable to their respective soil types in any of these test pit locations. Percolation rates for tests performed in the silt layers required 10-minute time intervals during the test period in order to record a measurable change in head. The water level was measured from a fixed reference point to the nearest 1/16th inch over each time interval. As a result, the rates were 2.5 and 2.9 min/inch at TP-8 and TP- 9, respectively. Comparatively, the percolation tests in the gravel layers required 1 minute time intervals with rates of 0.3 and 0.4 min/inch at TP-7 and TP-10, respectively.

Percolation tests in the silt layer (2 feet bgs) followed after a 2-hour soaking period. Depth of water was maintained at 6 inches above the gravel in the pipe. Measurements began following the soaking period at 10 minute intervals. The water level was measured from a fixed reference point to the nearest 1/16th inch over each time interval.The percolation rates were 2.5 and 2.9 min./in. at TP-8 and TP-9, respectively.

Percolation tests in the gravel layer (4 feet bgs) followed after a 2-hour soaking period. Depth of water was maintained at 6 inches above the gravel in the pipe. Measurements began following the soaking period at 1 minute intervals. The water level was measured from a fixed reference point to the nearest 1/16th inch over 1 minute intervals. The measurement time interval was altered due to the rapid rate of percolation occurring in the gravel layer. The percolation rates were 0.3 and 0.4 min./in. at TP-7 and TP-10, respectively.

Figure 2. Percolation pipe set-up prior to test at TP-7

CONCLUSIONS AND RECOMMENDATIONS

The purpose of this geotechnical investigation was performing percolation tests at the proposed leach field site to determine percolation rates of insitu soils at 2-and 4-foot depths (TP-7 through -10). Additionally, test pits were located along a proposed administration building expansion, access roadway, and a pole barn. Test Pits 1, 2, 3, and 4 were dug along the proposed road section with TP-1 also serving as a comparison to DOWL’s geotechnical investigation at the administration expansion project. TP-6 was located near the proposed pole barn. The site characterization at these sites was limited in depth by the excavator boom and stick reach to 9 feet bgs.

In regards to the administration building expansion, ground conditions during the geotechnical investigation were similar to materials encountered during the 2004 DOWL investigation.

The proposed roadway requires excavation of organics and frost-susceptable soils prior to construction of the road section. The minimum structural section for the proposed access road consists of the following (all material types are as defined in the ADOT&PF Standard Specifications for Highway Construction, latest edition):

• 2 inches HMA

• 2 inches Aggregate Base Coarse, Grading D-1

• 20 inches Selected Material, Type A with 6” maximum aggregrate size

• Suitable Subgrade

Or for Gravel

• 4” to 6” Aggregate Surface Course, Grading E-1

• 20 inches Selected Material, Type A with 6” maximum aggregrate size

• Suitable Subgrade

Sincerely, PND Engineers, Inc. | Anchorage

Torsten Mayrberger, PhD, PE Kannon Lee, EIT Principal Staff Engineer

Attachments:

Attachment A – Test Pit Logs

Attachment B – Summary of Sample Characteristics

Attachment C – Grain Size Distribution Plot

Attachment D – Moisture Content by Depth

A-1

ATTACHMENT A — TEST PIT LOGS

SOILS CLASSIFICATION, CONSISTENCY AND SYMBOLS

CLASSIFICATION

Identification and classification of soil samples is accomplished in general accordance with the ASTM version of the Unified Soil Classification

System (USCS) as presented in ASTM Standard D2487. The standard is a qualitative method of classifying soil into the following major divisions (1) coarse grained soil, (2) fine grained soil, and (3) highly organic soils. Classification is performed on a soil sample which passes the

75 mm (3 inch) sieve, oversize material (> 75 mm particles) is noted on the soil logs as well. Classification of oversize material is not always possible because the oversize particles are typically too large to be captured in the sampling equipment. Oversize materials greater than 300 mm (12 inches) are termed boulders, while materials between 75 mm and 300 mm are termed cobbles. Coarse grained soils are described as having 50% or more of the sample retained on the No. 200 sieve (0.075 mm) while fine grained soils will have 50% or more of the sample passing the No. 200 sieve. Coarse samples containing >50% material retained on the No. 4 sieve is classified as gravel. If a majority of the sample is retained on the No. 200 sieve but passes the No. 4 sieve it is classified as a sand. Fine grained soils are those having more than 50% of the sample passing the No. 200 sieve; these may be classified as silt or clay depending their Atterberg limits or observations of field consistency. Refer to the most recent version of ASTM D2487 for a complete discussion of the classification method.

SOIL CONSISTENCY - CRITERIA

Soil consistency as defined below and determined by normal field and laboratory methods applies only to non-frozen material. For these materials, the influence of such factors as soil structure, i.e. Fissure systems, shinkage cracks, slickensides, etc., must be taken into consideration in making any correlation with the consistency values listed below. In permafrost zones, the consistency and strength of frozen soils may vary significantly and unexplainably with ice content, thermal regime and soil type.

STANDARD PENETRATION TEST (BLOWS/FT)

RELATIVE TO DENSTIY/CONSISTENCY

N

0-4

4-10

10-30

30-50

> 50

Very Loose

Loose

Medium Dense

Dense

Very Dense

< 250

250 - 500

500 - 1000

1000 - 2000

2000 - 4000

> 4000

0-15%

15-35%

35-65%

65-85%

>85%

< 2

2 - 4

4 - 8

8 - 15

15 - 30

> 30

Very Soft

Soft

Medium Stiff

Stiff

Very Stiff

Hard

Ref: Terzaghi and Peck, Soil Mechanics in Engineering Practice, 3rd Edition, pg 60-63

ASTM D1586 Standard Test Method for Penetration Test and Split-Barrel Sampling of Soils

ASTM D2487 Standard Practice for Classification of Soils for Engineering Purposes (USCS)

LIST OF ABBREVIATIONS

Drill Methods:

AR Air Rotary

CC60 Continuous Coring (RS-60)

CD Case and Drill

CCm Continuous Coring (Macro Core)

CME Continuous Augering

CWR Casing with Wash Rotary

DH Down-hole hammer

HSA Hollow Stem Auger

MR Mud Rotary

NQ3 NQ3 Triple Tube

WR Wash Rotary

TP Test Pit

(*correlations based upon standard 1.4" O.D. split spoon and 140 lb manual hammer dropped from a height of 30 inches)

(*Adjust as required for other sampler types)

Particle Angularity

A Angular

R Rounded

SA Sub-Angular

SR Sub-Rounded

Particle Shape:

E Elongated

F Flat

Designed: PND

PNDDrawn:

Checked: PND

Project No.:

October 2020Date:

STANDARD

GEOTECHNICAL EXPLORATION

BOREHOLE LEGEND

UNDRAINED SHEAR STRENGTH

Density Relative Density N

Consistency psf

Color:

BK Black

BN Brown

DG Dark Brown

DG Dark Gray

G Gray

GG Greenish Gray

LB Light Brown

LG Light Gray

OG Olive Gray

P Pink

R Reddish

RO Rusty Orange

TN Tan

YO Yellowish Orange

BG Brownish Gray

Sample Methods:

AR Air Rotary

Cc Continuous Core

GR Grab Sample

Sh Oversize Split-Spoon

Ss Standard Split-Spoon

ST Shelby Tube

Cs Core Sample

1. Field descriptions may have been modified to reflect laboratory test results.

2. Descriptions on these boring logs apply only at the specific locations at the time the borings were drilled. They are not warranted to be representative of subsurface conditions at other locations or times.

3. Split spoon blow counts shown are uncorrected raw data. Various hammer sizes and split spoon sizes were used and have not been corrected to a Standard Penetration Test (SPT). Blow counts may vary substantially between SPT and these methods.

Depth (in feet) below the mudline.

Water Table depth.

Drilling methods recorded in depth intervals. Symbols explained on Fig. B-01.

Type of soil sample collected at depth interval depicted; symbols explained on Fig. B-04.

General description of soil encountered in a lithological layer.

Group symbols for soil and ice classification for each specimen.

Graphic depiction of lithological layers encountered. Graphic symbols explained in Fig. B-03 and B-04.

Number of blows to advance sampler each 6-inch interval using sampler type specified with a 30-inch drop.

Graphic log depicting moisture content and blow count per foot of soil specimens.

Results of other tests including hydrometer, Atterberg limits, etc.

Results of particle size distribution analysis.

Depth

Water Table

Drill Method

Sample Type

Material Description - General

Symbol

Graphic Log

Blows/ 6 in

Graphs

Other Tests

Size Distribution

Designed: PND

PNDDrawn:

Checked: PND

Project No.:

October 2020Date:

STANDARD

GEOTECHNICAL EXPLORATION

BOREHOLE LEGEND

GENERAL NOTES

SOIL LEGEND - (1 of 3)

GW

WELL GRADED

GRAVEL

GWs

WELL GRADED GRAVEL

WITH SAND

sGW

WELL GRADED SANDY

GRAVEL

GP

POORLY GRADED

GRAVEL

GPs

POORLY GRADED

GRAVEL WITH SAND

sGP

POORLY GRADED SANDY

GRAVEL

GW-GM

WELL GRADED

GRAVEL WITH SILT

(GW-GM)s

WELL GRADED

GRAVEL WITH SILT

AND SAND

s(GW-GM)

WELL GRADED

SANDY GRAVEL

WITH SILT

GW-GC

WELL GRADED

GRAVEL WITH CLAY

(GW-GC)s

WELL GRADED

GRAVEL WITH

CLAY AND SAND

s(GW-GC)

WELL GRADED

SANDY GRAVEL

WITH CLAY

GP-GM

POORLY GRADED

GRAVEL WITH SILT

(GP-GM)s

POORLY GRADED

GRAVEL WITH SILT

AND SAND

s(GP-GM)

POORLY GRADED SANDY

GRAVEL WITH SILT

GP-GC

POORLY GRADED

GRAVEL WITH CLAY

(GP-GC)s

POORLY GRADED

GRAVEL WITH CLAY

AND SAND

GM

SILTY GRAVEL

GMs

SILTY GRAVEL WITH

SAND

sGM

SILTY, SANDY GRAVEL

GC

CLAYEY GRAVEL

GCs

CLAYEY GRAVEL

WITH SAND

sGC

CLAYEY, SANDY

GRAVEL

GC-GM

SILTY, CLAYEY

GRAVEL

(GC-GM)s

SILTY, CLAYEY

GRAVEL WITH SAND

s(GC-GM)

SILTY, CLAYEY,

SANDY GRAVEL

SW

WELL GRADED SAND

SWg

WELL GRADED

SAND WITH GRAVEL

gSW

WELL GRADED

GRAVELLY SAND

SP

POORLY GRADED

SAND

Designed: PND

PNDDrawn:

Checked: PND

Project No.:

October 2020Date:

STANDARD

GEOTECHNICAL EXPLORATION

BOREHOLE LEGEND

SOIL LEGEND - (2 of 3)

SPg

POORLY GRADED

SAND WITH GRAVEL

gSP

POORLY GRADED

GRAVELLY SAND

SW-SM

WELL GRADED SAND

WITH SILT

(SW-SM)g

WELL GRADED

SAND WITH SILT

AND GRAVEL

g(SW-SM)

WELL GRADED

GRAVELLY SAND

WITH SILT

SW-SC

WELL GRADED SAND

WITH CLAY

(SW-SC)g

WELL GRADED

SAND WITH CLAY

AND GRAVEL

g(SW-SC)

WELL GRADED

GRAVELLY SAND

WITH CLAY

SP-SM

POORLY GRADED

SAND WITH SILT

(SP-SM)g

POORLY GRADED

SAND WITH SILT

AND GRAVEL

g(SP-SM)

POORLY GRADED

GRAVELLY SAND

WITH SILT

SP-SC

POORLY GRADED

SAND WITH CLAY

(SP-SC)g

POORLY GRADED

SAND WITH CLAY

AND GRAVEL

g(SP-SC)

POORLY GRADED

GRAVELLY SAND

WITH CLAY

SM

SILTY SAND

SMg

SILTY SAND WITH

GRAVEL

gSM

SILTY, GRAVELLY

SAND

SC

CLAYEY SAND

SCg

CLAYEY SAND WITH

GRAVEL

gSC

CLAYEY, GRAVELLY

SAND

SC-SM

SILTY, CLAYEY SAND

(SC-SM)g

SILTY, CLAYEY SAND

WITH GRAVEL

g(SP-SC)

POORLY GRADED

GRAVELLY SAND

WITH CLAY

CL

CLAY

CLs

CLAY WITH SAND

CLg

CLAY WITH GRAVEL

sCL

SANDY LEAN CLAY

gCL

GRAVELLY LEAN CLAY

sCLg

SANDY LEAN CLAY

WITH GRAVEL

gCLs

GRAVELLY LEAN CLAY

WITH SAND

Designed: PND

PNDDrawn:

Checked: PND

Project No.:

October 2020Date:

STANDARD

SOIL LEGEND - (3 of 3)

ML

SILT

MLs

SILT WITH SAND

MLg

LEAN SILT WITH

GRAVEL

sML

SANDY SILT

gML

GRAVELLY SILT

sMLg

SANDY SILT WITH

GRAVEL

gMLs

GRAVELLY SILT

WITH SAND

CH

FAT CLAY

CHs

FAT CLAY WITH SAND

CHg

FAT CLAY WITH GRAVEL

sCH

SANDY FAT CLAY

gCH

GRAVELLY FAT CLAY

gCHs

GRAVELLY FAT CLAY

WITH SAND

MH

ELASTIC SILT

MHs

ELASTIC SILT WITH

SAND

MHg

ELASTIC SILT WITH

GRAVEL

sMH

SANDY ELASTIC SILT

gMH

GRAVELLY ELASTIC

SILT

sMHg

SANDY ELASTIC SILT

WITH GRAVEL

gMHs

GRAVELLY ELASTIC

SILT WITH SAND

OH

ORGANIC SILT

OL

ORGANIC CLAY

ICE

ICE

ICE+S

ICE WITH SOIL

PT

PEAT

Designed: PND

PNDDrawn:

Checked: PND

Project No.:

October 2020Date:

STANDARD

OL

GWs sGW

GR

GR

GR

GR

TP

0 Dark brown organic SILT; OL. Sub-rounded gravel (max. 1/2-inch). ORGANICS and ROOTS.

Brown well-graded GRAVEL with SAND; GWs.

Rounded gravel (max. 2-inch). Cobbles present.

Gray well-graded SANDY GRAVEL; sGW. Rounded gravel (max. 2.5-inch). 10 - 15% cobbles by volume.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt Graphic

LogSymbolSoil ClassificationSa m pl e

Re co ve ry Sa m pl e Ty pe Dr ill M et ho d

(9 ft

De pt h

10/29/2020Review Date:

TMReviewed By:

JBRLogged By:

°W149.37457Longitude:°N60.40688Latitude:

NAD83 AKSP Zone 4Horizontal Datum:202080Project Number:

USFS Kenai Lake Work CenterProject:

TP-1LOG OF BOREHOLE

11Page: ofJohnDriller:

Hitachi Zaxis 50-UDrill Equipment:

USFSDrilling Contractor:

10/13/2020 Drill Start:

USFSClient:

ft9Borehole terminated at

Gravel = 44% Sand = 50% Fines = 6%

Gravel = 67% Sand = 29% Fines = 5%

57%

OL

MLs g(SW-SM)

GWs

GR

GR

GR

GR

TP

0 Dark brown organic SILT; OL. Rounded gravel (max.

1/2-inch). 25% Fibrous ORGANICS.

Gray SILT with SAND; MLs. 5% Fibrous ORGANICS.

Gray well-graded GRAVELLY SAND with SILT;

g(SW-SM). Sub-rounded gravel (max. 2.5-inch).

Gray well-graded GRAVEL with SAND; GWs.

Sub-rounded gravel (max. 3-inch). 5% cobbles by volume.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt Graphic

LogSymbolSoil ClassificationSa m pl e

Re co ve ry Sa m pl e Ty pe Dr ill M et ho d

(9 ft

De pt h

10/29/2020Review Date:

TMReviewed By:

JBRLogged By:

°W149.37327Longitude:°N60.40703Latitude:

NAD83 AKSP Zone 4Horizontal Datum:202080Project Number:

USFS Kenai Lake Work CenterProject:

TP-2LOG OF BOREHOLE

11Page: ofJohnDriller:

Hitachi Zaxis 50-UDrill Equipment:

USFSDrilling Contractor:

10/13/2020 Drill Start:

114%

PT

MLs sGW

CL

sGW

GR

GR

GR

GR

GR

TP

0 Brown PEAT; PT. 95% Fibrous ORGANICS.

Brown SILT with SAND; MLs. Sub-angular gravel (max. 1/2-inch).

Gray well-graded SANDY GRAVEL; sGW.

Sub-rounded/sub-angular gravel (max. 3-inch).

Light gray lean CLAY; CL. Sub-angular gravel (max.

1/2-inch).

Gray well-graded SANDY GRAVEL; sGW.

Sub-rounded/sub-angular gravel (max. 3-inch).

Trace cobbles.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt Graphic

LogSymbolSoil ClassificationSa m pl e

Re co ve ry Sa m pl e Ty pe Dr ill M et ho d

(9 ft

De pt h

10/29/2020Review Date:

TMReviewed By:

JBRLogged By:

°W149.37307Longitude:°N60.40727Latitude:

NAD83 AKSP Zone 4Horizontal Datum:202080Project Number:

USFS Kenai Lake Work CenterProject:

TP-3LOG OF BOREHOLE

11Page: ofJohnDriller:

Hitachi Zaxis 50-UDrill Equipment:

USFSDrilling Contractor:

10/13/2020 Drill Start:

Gravel = 67% Sand = 30% Fines = 3%

78%

GPs

OL

sGW

GR

GR

GR

GR

TP

0 Gray poorly graded GRAVEL with SAND; GPs.

Sub-angular gravel (max. 1-inch). Compacted fill material.

Brownish gray organic SILT; OL.

Gray well-graded SANDY GRAVEL; sGW.

Sub-rounded/sub-angular gravel (max. 3-inch). 20% cobbles by volume.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt Graphic

LogSymbolSoil ClassificationSa m pl e

Re co ve ry Sa m pl e Ty pe Dr ill M et ho d

(9 ft

De pt h

10/29/2020Review Date:

TMReviewed By:

JBRLogged By:

°W149.37232Longitude:°N60.40663Latitude:

NAD83 AKSP Zone 4Horizontal Datum:202080Project Number:

USFS Kenai Lake Work CenterProject:

TP-4LOG OF BOREHOLE

11Page: ofJohnDriller:

Hitachi Zaxis 50-UDrill Equipment:

USFSDrilling Contractor:

10/13/2020 Drill Start:

sGP sGW g(SW-SM) s(GW-GM)

GR

GR

GR

GR

TP

0 Dark gray poorly graded SANDY GRAVEL; sGP.

Sub-angular gravel (max. 1-inch). Compacted fill material.

Gray well-graded SANDY GRAVEL; sGW.

Sub-rounded/sub-angular gravel (max. 2-inch).

Compacted fill material.

Brown well-graded GRAVELLY SAND with SILT;

g(SW-SM). Sub-rounded gravel (max. 3-inch). Trace cobbles.

Gray well-graded SANDY GRAVEL with SILT;

s(GW-GM). Sub-rounded/sub-angular gravel (max.

3-inch). Cobbles present.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt Graphic

LogSymbolSoil ClassificationSa m pl e

Re co ve ry Sa m pl e Ty pe Dr ill M et ho d

(9 ft

De pt h

10/29/2020Review Date:

TMReviewed By:

JBRLogged By:

°W149.37013Longitude:°N60.40542Latitude:

NAD83 AKSP Zone 4Horizontal Datum:202080Project Number:

USFS Kenai Lake Work CenterProject:

TP-6LOG OF BOREHOLE

11Page: ofJohnDriller:

Hitachi Zaxis 50-UDrill Equipment:

USFSDrilling Contractor:

10/13/2020 Drill Start:

95%OL

s(GP-GM) s(GW-GM)

GR

GR

GR

TP

0 Dark brown organic SILT; OL. Sub-rounded gravel (max. 1/2-inch). 35% fibrous ORGANICS and ROOTS.

Brownish gray poorly graded SANDY GRAVEL with SILT; s(GP-GM). Sub-rounded gravel (max. 2-inch).

Gray well-graded SANDY GRAVEL with SILT;

s(GW-GM). Sub-rounded/sub-angular gravel (max.

3-inch). 20% cobbles by volume.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt Graphic

LogSymbolSoil ClassificationSa m pl e

Re co ve ry Sa m pl e Ty pe Dr ill M et ho d

(9 ft

De pt h

10/29/2020Review Date:

TMReviewed By:

JBRLogged By:

°W149.37185Longitude:°N60.40528Latitude:

NAD83 AKSP Zone 4Horizontal Datum:202080Project Number:

USFS Kenai Lake Work CenterProject:

TP-7LOG OF BOREHOLE

11Page: ofJohnDriller:

Hitachi Zaxis 50-UDrill Equipment:

USFSDrilling Contractor:

10/13/2020 Drill Start:

86%OL

MLs sGP sGW

GR

GR

GR

GR

TP

0 Dark brown organic SILT; OL. 55% fibrous

ORGANICS.

Light gray SILT with SAND; MLs. Rounded gravel (max. 1-inch). 5% ORGANICS.

Brown poorly graded SANDY GRAVEL; sGP.

Sub-rounded/sub-angular gravel (max. 3-inch). 25% cobbles by volume.

Gray well-graded SANDY GRAVEL; sGW. Rounded gravel (max. 3-inch). 2-foot boulders present.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt Graphic

LogSymbolSoil ClassificationSa m pl e

Re co ve ry Sa m pl e Ty pe Dr ill M et ho d

(9 ft

De pt h

10/29/2020Review Date:

TMReviewed By:

JBRLogged By:

°W149.37103Longitude:°N60.40503Latitude:

NAD83 AKSP Zone 4Horizontal Datum:202080Project Number:

USFS Kenai Lake Work CenterProject:

TP-8LOG OF BOREHOLE

11Page: ofJohnDriller:

Hitachi Zaxis 50-UDrill Equipment:

USFSDrilling Contractor:

10/13/2020 Drill Start:

264%OL

CLs sGP

GPs

GR

GR

GR

GR

TP

0 Brown organic SILT; OL. 70% fibrous ORGANICS.

Light gray lean CLAY with SAND; CLs.

Brown poorly graded SANDY GRAVEL; sGP.

Sub-rounded gravel (max. 2-inch).

Light gray poorly graded GRAVEL with SAND; GPs.

Sub-rounded/sub-angular gravel (max. 3-inch). 1-foot boulders present.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt Graphic

LogSymbolSoil ClassificationSa m pl e

Re co ve ry Sa m pl e Ty pe Dr ill M et ho d

(9 ft

De pt h

10/29/2020Review Date:

TMReviewed By:

JBRLogged By:

°W149.37223Longitude:°N60.40488Latitude:

NAD83 AKSP Zone 4Horizontal Datum:202080Project Number:

USFS Kenai Lake Work CenterProject:

TP-9LOG OF BOREHOLE

11Page: ofJohnDriller:

Hitachi Zaxis 50-UDrill Equipment:

USFSDrilling Contractor:

10/13/2020 Drill Start:

914%

PT

sML sGW

GR

GR

GR

TP

0 Tan PEAT; PT. 100% fibrous ORGANICS and PEAT.

WOOD at surface.

Brownish gray SANDY SILT; sML.

Gray well-graded SANDY GRAVEL; sGW.

Sub-rounded/sub-angular gravel (max. 3-inch). 15% cobbles by volumes.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt Graphic

LogSymbolSoil ClassificationSa m pl e

Re co ve ry Sa m pl e Ty pe Dr ill M et ho d

(9 ft

De pt h

10/29/2020Review Date:

TMReviewed By:

JBRLogged By:

°W149.37168Longitude:°N60.40507Latitude:

NAD83 AKSP Zone 4Horizontal Datum:202080Project Number:

USFS Kenai Lake Work CenterProject:

TP-10LOG OF BOREHOLE

11Page: ofJohnDriller:

Hitachi Zaxis 50-UDrill Equipment:

USFSDrilling Contractor:

10/13/2020 Drill Start:

B-1

ATTACHMENT B — SUMMARY OF SAMPLE CHARACTERISTICS

B o re h o le

S a m p le

F ro m

T o

S a m p le

M e th o d

L iq u id

L im it (%

P la stic L im it (%

G ra v e l

S a n d

F in e s*

Gradation (%)

M a x P a rtic le S ize

(in

S a lin ity (p p t)

M o istu re

P a rtic le S h a p e

P a rtic le

A n g u la rity

O th e r T e sts

L a b o ra to ry

C la ssific a tio n

Summary of Sample Characteristics

Project: USFS Kenai Lake Work Center

Project #: 202080

Client: USFS

TP-1 1 0 0.5 1/2 49 SROLGR

TP-1 2 1 1.5 2.5 7 B SRGWsGR

TP-1 3 2.5 3.5 2 4 B RGWsGR

TP-1 4 8.5 9 2.5 5 SRsGWGR

TP-10 1 1.5 2 914PTGR

TP-10 2 2.5 3 37sMLGR

TP-10 3 8 9 3 6 SR-SAsGWGR

TP-2 1 0.5 1 1/2 57 ROLGR

TP-2 2 1 2 47MLsGR

TP-2 3 2 4 44.3 49.8 5.9 2.5 5 SRg(SW-SM)GR

TP-2 4 8.5 9 66.5 28.6 4.9 3.0 5 SRGWsGR

TP-3 1 0.5 1 114PTGR

TP-3 2 1 1.5 1/2 48 SAMLsGR

TP-3 3 3 4 3 4 B SR-SAsGWGR

TP-3 4 4.5 5 1/2 35 ACLGR

TP-3 5 8.5 9 3 6 B SR-SAsGWGR

TP-4 1 0 1 1 4 SAGPsGR

TP-4 2 1 1.5 78OLGR

TP-4 3 1.5 3 67.0 30.4 2.6 2.5 4 SR-SAsGWGR

TP-4 4 8.5 9 3.0 5 SR-SAsGWGR

TP-6 1 0 0.5 1 5 SAsGPGR

TP-6 2 1.5 2 2 4 SR-SAsGWGR

TP-6 3 3 4 3 5 SRg(SW-SM)GR

TP-6 4 8.5 9 3 4 B SR-SAs(GW-GM)GR

TP-7 1 0 0.5 1/2 95 ROLGR

TP-7 2 1.5 2.5 2 6 SRs(GP-GM)GR

TP-7 3 8.5 9 3 4 SR-SAs(GW-GM)GR

TP-8 1 0 0.5 86OLGR

TP-8 2 0.5 1 1 28 B RMLsGR

TP-8 3 3 3.5 3 3 B SR-SAsGPGR

TP-8 4 8.5 9 3 5 E RsGWGR

*Fines type and content estimated with ASTM D2488 when ASTM D422 or D4318 were not performed

B o re h o le

S a m p le

F ro m

T o

S a m p le

M e th o d

L iq u id

L im it (%

P la stic L im it (%

G ra v e l

S a n d

F in e s*

Gradation (%)

M a x P a rtic le S ize

(in

S a lin ity (p p t)

M o istu re

P a rtic le S h a p e

P a rtic le

A n g u la rity

O th e r T e sts

L a b o ra to ry

C la ssific a tio n

Summary of Sample Characteristics

Project: USFS Kenai Lake Work Center

Project #: 202080

Client: USFS

TP-9 1 0 0.5 264OLGR

TP-9 2 1.5 2 32CLsGR

TP-9 3 3 4 2 11 SRsGPGR

TP-9 4 8 9 3 5 B SR-SAGPsGR

35 samples

*Fines type and content estimated with ASTM D2488 when ASTM D422 or D4318 were not performed

C-1

ATTACHMENT C — GRAIN SIZE DISTRIBUTION PLOT

coarse finemediumcoarse fine

SANDCOBBLE GRAVEL

Grain Size Distribution

FinesSandGravel P10D50Laboratory Classification* Gradation (%)

ToFromBorehole Sample

US Sieve Opening (in.) US Sieve Numbers

13 #40 #100#42 1.5 ¾ ⅜ #10 #20 #60 #140 #200

Project: USFS Kenai Lake Work Center

Project #: 202080

Client: USFS

35.33.75.949.844.342TP-2 g(SW-SM)3

21.312.84.928.666.598.5TP-2 GWs4

19.99.62.630.467.031.5TP-4 sGW3

*Fines type estimated with ASTM D2488 when ASTM D422 or D4318 were not performed

D-1

ATTACHMENT D — MOISTURE CONTENT BY DEPTH

Client: United States Forest Service Project: Kenai Lake Work Station Project #: 202080

Location: Moose Pass, AK Reviewed By: TM Review Date: 10/29/2020

MOISTURE CONTENT BY DEPTH

KENAI LAKE WORK CENTER ROAD SECTION

0 10 20 30 40 50 Moisture Content (%)

De pt h (ft

Borehole

TP-1

TP-2

TP-3

TP-4

Client: United States Forest Service Project: Kenai Lake Work Station Project #: 202080

Location: Moose Pass, AK Reviewed By: TM Review Date: 10/29/2020

MOISTURE CONTENT BY DEPTH

KENAI LAKE WORK CENTER LEACH FIELD

0 10 20 30 40 50 Moisture Content (%)

De pt h (ft

Borehole

TP-7

TP-8

TP-9

TP-10