Keen_Eye_Headquarters_Geotechnical_Report_0001.pdf

B-1

Keen Eye Headquarters Lake Trail Boardwalk and Observation Platform Foundation Design

Kenai National Wildlife Refuge Geotechnical Report

Prepared by:

PND Engineers, Inc.

1506 West 36th Avenue Anchorage, AK 99503

July 2023

Prepared for:

U.S. Fish & Wildlife Service 1011 E. Tudor Road Anchorage, AK 99503

KEEN EYE HEADQUARTERS LAKE

GEOTECHNICAL REPORT

ii JULY 2023

TABLE OF CONTENTS

1. INTRODUCTION

2. BACKGROUND

2.1 BOREHOLE LOCATIONS

2.2 INVESTIGATION DESCRIPTION

3. SITE AND SUBSURFACE CHARACTERIZATION

3.1 LABORATORY CLASSIFICATION

3.2 SUBSURFACE SOIL PROPERTIES IN SUMMARY

3.2.1 Groundwater

3.2.2 Moisture Content

3.3 IDEALIZED SOIL PROFILE

4. SEISMIC DESIGN

4.1 LIQUEFACTION

5. SITE RECOMMENDATIONS

5.1 BOARDWALK

5.2 OBSERVATION PLATFORM

5.2.1 Options 1 and 2

5.2.2 Options 3 and 4

6. LIMITATIONS AND CLOSURE

7. REFERENCES

LIST OF APPENDICES

APPENDIX A. BOREHOLE LOGS .................................................................................................................. A-1

APPENDIX B. SUMMARY OF LAB AND FIELD CHARACTERISTICS ............................................... B-1

APPENDIX C. GRAIN SIZE DISTRIBUTION PLOTS ................................................................................ C-1

APPENDIX D. MOISTURE CONTENT BY DEPTH GRAPH .................................................................. D-1

APPENDIX E. SPT BLOWCOUNT CORRECTION PLOT ........................................................................ E-1

APPENDIX F. ATTERBERG LIMIT PLOTS ................................................................................................. F-1

APPENDIX G. SITE-SPECIFIC SEISMIC AND LIQUEFACTION ANALYSIS .................................... G-1 ii JULY 2023

LIST OF FIGURES

Figure 1. Project Vicinity Map Figure 2. As-Built Borehole locations Figure 3. Wooden Bracing Post connected to Helical Pile (Techno Metal Post)

LIST OF TABLES

Table 1. As-Built Borehole Locations Table 2. Summary of Laboratory Tests Table 3. Average Moisture Content by Soil Type of Material Encountered During Investigation Table 4. Idealized Soil Profile Table 5. Idealized Liquified Soil Profile Table 6. Seismic Design Parameters Table 7. Observation Deck Installment Options

1 JULY 2023

KEEN EYE HEADQUARTERS LAKE

GEOTECHNICAL REPORT

1. INTRODUCTION

Between April 24 and April 25, 2023, PND Engineers, lnc. (PND), together with drilling contractors GeoTeK Alaska, performed a geotechnical investigation to characterize in-situ soil conditions at the Kenai Keen Eye Trail located near Headquarters Lake in Soldotna, Alaska. The geotechnical investigation was performed in support of the replacement of the boardwalk and observation platform and the helical pile foundation analysis. The following paragraphs summarize the findings of the geotechnical investigation at the site.

The report contains seven appendices:

Appendix A – Borehole Logs presents the complete borehole log set from the exploratory borings of this investigation.

Appendix B – Summary of Lab and Field Characteristics presents the complete summary of results from the lab testing program.

Appendix C – Grain Size Distribution Plots presents the complete set of particle size distribution plots (gradations) as performed in the lab program.

Appendix D – Moisture Content by Depth Graphs presents the complete summary of moisture content by depth from the results of the laboratory tests.

Appendix E – Corrected SPT Blow Counts

Appendix F – Atterberg Limit Plots

Appendix G – Site-Specific Seismic and Liquefaction Analysis

2 JULY 2023

Figure 1. Project Vicinity Map

2. BACKGROUND

The Keen Eye Nature trail was constructed in 1981 and begins at the FWS Kenai National Wildlife Refuge Headquarters and Visitor Center. The trail then meanders through the wooded area between the Visitor center and Headquarters Lake. The trail offers several routing options that vary in length from 0.25 miles one way to a 0.75-mile loop. This project is focused on the timber boardwalk located at the end of the 0.25-mile out and back trail. This portion of the trail is used year-round for educational purposes and recreation. The boardwalk is approximately 295 feet long and 4 feet wide and leads to a timber observation platform on the shore of Headquarters Lake.

The existing boardwalk is supported by 8x8-inch sleepers that rest directly on the existing ground. The boardwalk’s walking surface is approximately 12-18 inches above existing ground and relatively flat.

Evidence of frost heaving along the boardwalk length was not observed and the boardwalk appears to be stable. The posts supporting the observational platform showed evidence of frost heaving. The US Fish & Wildlife Service (FWS) is seeking to replace the existing Keen Eye Trail boardwalk and observation platform. Table 1 shows borehole locations in tabular form, and Figure 2 shows the borehole locations.

2.1 BOREHOLE LOCATIONS

Table 1. As-Built Borehole Locations

Borehole Latitude1 Longitude1 Total

Depth (ft)

BH-1 60.463422°N 151.070925°W 36

BH-2 60.463472°N 151.070944°W 30.5

1 Horizontal datum NAD83 AKSP Zone 4

Headquarters Lake

3 JULY 2023

Figure 2. As-Built Borehole locations

2.2 INVESTIGATION DESCRIPTION

The drilling was performed using a 6610DT Geoprobe drill rig. The field sampling used a 3-inch outside diameter (O.D) Modified Penetration Test (MPT) split spoon sampler. The sampler was advanced using a 340-pound automatic drop hammer free-falling 30 inches for a distance of 18-inches and 24-inches, measured at 6-inch intervals. The number of blows required to drive the sampler a 6-inch interval was recorded on the borehole logs. The blow counts shown on the borehole logs are field values that have not been corrected for overburden, rod length, sample size, or other factors. Corrected blowcounts were used to establish engineering soil properties and characterize soil density as shown in the borehole logs.

Soil samples were collected every 2.5 feet in the top 10 feet below ground surface (bgs) and every 5 feet proceeding, to obtain representative samples of the subsurface soil conditions. The recovered soils were field classified following the Visual Manual Procedure according to ASTM D2488. Representative samples went to PND’s Anchorage Soil-Material Lab for field verification and lab testing. Site and Subsurface characterizations are described in Section 3.

4 JULY 2023

3. SITE AND SUBSURFACE CHARACTERIZATION

This section summarizes the surface and subsurface characterization of the site investigated. The soil characterizations are based on PND field logging observations following the Standard Guide for Field Logging of Subsurface Explorations of Soil and Rock (ASTM D5434-03). Soil classifications in this report use the Standard Practice for Classification of Soils for Engineering Purposes (USCS) (ASTM D2487) using abbreviated soil classification symbols and standard prefixes and suffixes to indicate the percentage of secondary soil component. For example, a well graded Sand with gravel (SWg) has between 15 and 30% gravel, whereas a gravelly well-graded Sand (gSW) has between 30 and 50% gravel.

3.1 LABORATORY CLASSIFICATION

Representative samples 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 30 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 D2487, D2488)

• Particle Size Analysis (ASTM D422)

• Fines Wash (ASTM D1140)

• Atterberg Limits (ASTM D4318)

Table 2. Summary of Laboratory Tests Test Type Quantity

Moisture Content with Classification

(ASTM D2487 / D2488 / D2216) 19

Gradation of Soils (ASTM D6913) 1 Fines Wash (ASTM D1140) 6 Atterberg Limits (ASTM D4318) 4

The results of the laboratory testing program are shown in Appendix B, C, D, E, and F. The appendices include a comprehensive tabulated summary of test results and classifications. The appendices also include grain size distribution plots and moisture contents by depth. Lab results are shown in the borehole logs at corresponding columns with given soil lithologies.

3.2 SUBSURFACE SOIL PROPERTIES IN SUMMARY

The following sections describe the soils encountered at the Keen Eye Headquarters Lake Trail near the boardwalk and the observation platform, with summary descriptions of soil properties, such as moisture content and lithologies.

3.2.1 GROUNDWATER

Ground water was encountered at 14 feet bgs for both BH-1 and BH-2, at time of drilling. Boreholes BH-1 and BH-2 are located approximately 12 and 30 feet from the shore, respectively.

5 JULY 2023

3.2.2 MOISTURE CONTENT

Table 3 provides a summary of the average representative moisture contents by soil type These characterizations are generalized to simply capture the general soil properties by depth. Moisture content (MC) by depth for individual boreholes are shown in Appendix D. Moisture content is also provided in the attached lab Summary of Sample Characteristics in Appendix B and Borehole logs in Appendix A.

Table 3. Average Moisture Content by Soil Type of Material Encountered During Investigation

Soil Type (USCS) MC Range

MC Average

PT 387-793 524

ML 18-33 26

MLs 35 35 sML 17-29 23 gMLs 11 11

SP-SM 16 16

SP 25 25

(SP-SM)g 15 15

3.3 IDEALIZED SOIL PROFILE

Based on laboratory testing and SPT blowcounts corrected to (N1)70, the soil at the site can generally be described as 9 feet of very loose Peat followed by 14.5 feet of Silt with sand, 5.5 feet of sandy Silt with gravel, 5 feet of Sand with silt, and remaining soil as Sand with silt and gravel. Table 4 presents the idealized soil profile with the recommended engineering properties (for nonliquefied analysis) and Table 5 presents a liquefied idealized soil profile.

Table 4. Idealized Soil Profile

Thickness (ft)

Depth Range (ft)

Material Type Consistency

Effective Friction Angle

(deg)1 Bulk Unit

Weight (pcf)1 Effective

Cohesion (psf)2 9 0-9 Peat Very Loose 0 75 0

14.5 9-23.5 Silt with sand Loose 30 85 0

5.5 23.5-29 sandy Silt with gravel

Medium dense 32 95 0

5 29-34 Sand with silt Dense 36 120 0

2 34-36

Sand with silt and gravel Dense 36 120 0

1Based on published data and borehole blowcount correlations (Foundation Analysis and Design, Bowles 1996) 2Based on NAVAC Design Manual 7.02 (1985)

6 JULY 2023

Table 5. Idealized Liquified Soil Profile

Thickness (ft)

Depth Range (ft)

Material Type Consistency

Effective Friction Angle

(deg)1 Bulk Unit

Weight (pcf)1 Effective

Cohesion (psf)2 9 0-9 Peat Very Loose 0 75 0

5 9-14 Silt with sand Loose 0 85 0

9.5 14-23.5 Silt with sand Loose 0 85 0

5.5 23.5-29 sandy Silt with gravel

Medium dense 0 95 0

5 29-34 Sand with silt Dense 36 120 0

2 34-36

Sand with silt and gravel Dense 36 120 0

1Based on published data and borehole SPT blowcount correlations (Foundation Analysis and Design, Bowles 1996) 2Based on NAVAC Design Manual 7.02 (1985)

4. SEISMIC DESIGN

Seisimic design for liquefaction potential is required by industry standards to be evaluated at the Maximum Considered Earthquake (MCE) or the 2% probability of exceedance in 50 years. This correlates to a 2,475-year return period. Seismic design parameters based on maps/data provided by Applied Technology Council (ATC Hazards Tool, https://hazards.atcouncil.org/) are provided in Table 6.

Reference manual American Society of Civil Engineers ASCE Minimum Design Loads and Associated Criteria for Buildings and Other Structures.

Soils at the site were classified as Site Class D based on American Association of State Highway and Transportation Officials AASHTO LFRD Bridge design Specifications. The code specifies that if average field SPT blowcount (N) are generally between 15 < N < 50 the site classification is Site Class D, which reflects the blowcounts observed at the site for the upper 40 feet of the soil profile. Note, that the top 30 feet of soil were N <15, but below 30 feet bgs the blowcount range was 15 < N < 50. Detailed SPT blowcount correction data can be found in Appendix E

7 JULY 2023

Table 6. Seismic Design Parameters

Earthquake Level Return Period

MCE 2475 years (2% Probability of

Exceedance in 50 years)

Risk Category I

Site Class D Peak Ground Acceleration

(PGA) 0.5

Site Amplification Factor

(FPGA) 1.2

Site-Adjusted Peak Ground

Acceleration (PGAM) 0.6 Ss (0.2-sec spectral acceleration) 1.5 S1 (1.0-sec spectral acceleration) 0.6

Moment Magnitude (Mw) 9.2

4.1 LIQUEFACTION

Liquefaction is a phenomenon where saturated soil loses its strength and behaves like a viscous liquid due to ground movement or other sudden changes in stress. Soils during liquefaction have functionally zero strength and can undergo large vertical and lateral displacements. Earthquake-induced liquefaction generally occurs only under particular conditions, including a high groundwater table, strong earthquake ground shaking with long duration, and loose uniform sands.

A liquefaction potential analysis was performed using results of the geotechnical investigation SPT blowcounts, laboratory tests results, and the liquefaction potential analysis procedure as described by Youd and Idriss (2001). Appendix G shows the results of the liquefaction analysis with respect to earthquake magnitude of loading versus elevation. Factors-of-safety against liquefaction (FSliq) less than

1.0 indicate liquefaction potential, while FSliq greater than 1.0 indicate the soil is unlikely to undergo liquefaction. The liquefaction analysis is under 14-foot water table conditions.

Based on the liquefaction analysis and consistency of the in-situ soils, material encountered approximately 14-29 feet bgs are potentially liquefiable in BH-2. BH-1 had potentially liquefiable soils from 14-20 feet bgs. These soils showed potential for liquefaction under MCE loading, as Factor of Safety (FSliq) was less than 1. Settlement due to liquefaction may be up to 7.71 inches (Ishihara 1992) at the project site. The full liquefaction analysis can be seen in Appendix G.

8 JULY 2023

5. SITE RECOMMENDATIONS

5.1 BOARDWALK

The existing boardwalk is supported by 8x8-inch sleepers that rest directly on the existing ground. The boardwalk’s walking surface is approximately 12 to 18 inches above existing ground and relatively flat.

Evidence of frost heaving along the boardwalk length was not observed and the boardwalk appears to be stable. The new recommended boardwalk design will use 8x8-inch sleepers consistent with the previous structure. An 8x8-inch and 5-foot-wide wooden block sleeper resting on the soil surface had a bearing capacity of 344 psf, assuming the Organic layer had a friction angle of 26° for calculation purposes.

5.2 OBSERVATION PLATFORM

From previous site investigations, the observation platform showed evidence of frost heaving. To attain frost depth information, a Modified Berggren calculation was performed, comparison with Soldotna Municipal Building Codes, and assumed frost depth of 42-inches was used for analyses. To mitigate the frost heaving issues, helical piles should be considered for supporting the platform. The helical design of the shafts makes them highly effective in resisting uplift forces. 4 scenarios with various helical pile layout analysis were performed. Options 1 and 2 use a 13 helical pile system. Options 3 and 4 use a 21 helical pile system. Pile embedment depths are calculated assuming both liquefied soil conditions and non-liquefied conditions.

5.2.1 OPTIONS 1 AND 2

Helical Pile Parameters

• 13 Helical Pile Layout o 34.5-inch helix spacing o 2 helices per pile

• Diameter o 3-inch diameter shaft o 8-inch diameter helices o 3-inch helix pitch

• Required Axial Load o Max 9.5 Kips

• Required Lateral Load o 0.7 Kips

• Frost Jacking Heave Force o 2.0 Kips

• Soil Profile o Liquefied soil profile o Non-liquefied soil profile

9 JULY 2023

5.2.2 OPTIONS 3 AND 4

Helical Pile Parameters

• 21 Helical Pile Layout o 34.5-inch helix spacing o 2 helices

• Diameter o 3-inch diameter shaft o 8-inch diameter helices o 3-inch helix pitch

• Required Axial Load o Max 3.7 Kips

• Required Lateral Load o 0.5 Kips

• Heave Force o 2.0 Kips

• Soil Profile o Liquefied soil profile o Non-liquefied soil profile

Table 7 shows embedment depth and installation torque for Options 1 through 4 for assumed liquefied ground after an MCE event or embedment depth or embedment depth required for static capacity and ignoring an earthquake event.

Table 7. Observation Deck Installment Options

Option Quantity of Piles Status of Ground

Condition

Pile Embedment Depth

(ft)

Installation Torque

(kip-feet) 1 13 Assumes Liquefied 35 1.17 2 13 Ignores Liquefaction 18 1.17 3 21 Assumes Liquefied 35 0.455 4 21 Ignores Liquefaction 18 0.455

The upper 15 to 30 ft of the soil strata is potentially liquefiable during an MCE level earthquake event.

Since the soil in the liquefiable zone will behave like a viscous fluid the pile length in these zones will have no capacity in the axial or lateral aspects. It can be assumed under such an earthquake the deck will be damaged and likely need to be rebuilt if embedment depths of the helical piles are based on non-earthquake/liquefaction conditions. If the embedment depths are advanced to 35 feet presumably the deck will survive a liquefaction event during an MCE event. However, the damage could be large enough that larger repairs would still be necessary. Costs can be reduced as well as an increase in time efficiencies by implementing the shorter pile embedment length (18 ft).

Above ground bracing as shown in Figure 3 is recommended for lateral stability of the viewing deck.

Lateral bracing systems are generally available for any proprietary system.

10 JULY 2023

Figure 3. Wooden Bracing Post connected to Helical Pile (Techno Metal Post)

6. LIMITATIONS AND CLOSURE

The information submitted in this report is based on our interpretation of data from a field and lab geotechnical investigation conducted for this project and other sources discussed in this report. Effort was made to obtain information that is representative of the conditions at the site. However, actual subsurface conditions may vary and additional information may be discovered that could impact our recommendations. If conditions significantly different from those indicated in this report are encountered by subsequent investigations or during construction, the recommendations of this report should be reviewed by PND.

Sincerely, PND Engineers, Inc.

Torsten Mayrberger, PhD, PE Dominic Russo, EIT Principal Staff Engineer II

11 JULY 2023

7. REFERENCES

Alaska Department of Natural Resources (DNR) and Division of Oil and Gas (DOG). Regional Geology of the North Slope of Alaska. Map and poster published April 2008.

Alaska Geologic Materials Center (GMC). (2013). Compilation of data by the Alaska Oil and Gas Conservation Coalition. Web source link: http://doa.alaska.gov/ogc/publicdb.html.

ASTM D420-98, “Standard Guide to Site Characterization for Engineering Design and Construction Purposes”, American Society for Testing and Materials, ed. 2012.

ASTM D422-63, “Standard Test Method for Particle Size Analysis of Soils”, American Society for Testing and Materials, ed. 2012.

ASTM D1557-12, “Standard Test Method for Laboratory Compaction Characteristics of Soil Using Modified Effort”, American Society for Testing and Materials, ed. 2012.

Helical Piers. Techno Metal Post. (n.d.). Retrieved May 2, 2023, from https://www.technometalpost.com/en-US/helical-piers/ http://doa.alaska.gov/ogc/publicdb.html

A-1 JULY 2023

Appendix A. Borehole logs

Fines = 62.9%

Fines = 25.3%

Fines = 7%

Gravel = 22% Sand = 69% Fines = 9%

PL = 19

LL = 23

793%

490%

570%

508%

PT

sML

ML

MLs gMLs

SP-SM

(SW-SM)g

GR

Sh

Sh

Sh

Sh

Sh

Sh

Sh

Sh

Sh35

0 Very loose, brown PEAT; PT. Fibrous and ROOTS.

Very loose, brown PEAT; PT. Organics.

Very loose, brown PEAT; PT. Organics with ROOTS.

Very loose, gray SANDY SILT; sML.

Medium-dense, blue-gray SILT; ML. Interbedded with Sand.

Loose, blue-gray SILT with SAND; MLs.

Dense, gray GRAVELLY SILT with SAND; gMLs.

Sub-rounded/sub-angular gravel (max. 1-inch).

Lignite encountered.

Very dense, gray poorly graded SAND with SILT;

SP-SM.

Dense, gray well-graded SAND with SILT and GRAVEL; (SW-SM)g. Sub-rounded gravel (max.

2-inch). Trace of Gravel.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt

Bl ow s/ in

Graphic LogSymbolSoil ClassificationSa m pl e

Re co ve ry

Sa m pl e

Ty pe

Dr ill

M et ho d

( f t)

De pt h

Logged By: KL, DJR Reviewed By: TM Review Date: 7/6/2023Longitude: 151.07092°W

Horizontal Datum: WGS 84 Latitude: 60.46342°N05Project Phase:

211147Project Number:

Headquarters Lake Educational AreaProject:

LOG OF BH-1

11Page: ofJBDriller:

6610DTDrill Equipment:

GeoTekDrilling Contractor:

4/25/2023 Drill Start:

US Fish & Wildlife ServiceClient:

30.5Borehole terminated at

Fines = 79%

Fines = 55.9%

Fines = 1.6%

PL = 16

PL = 27

PL = 15

LL = 20

LL = 37

LL = 16

387%

395%

PT

ML

sMLg

ML

sML

SP

GR

GR

Sh

Sh

Sh

Sh

Sh

Sh30

0 Very loose, brown PEAT; PT. Little Fibrous, mostly all ORGANICS.

Very loose, brown PEAT; PT. Mostly all ORGANICS.

Loose, blue-gray SILT; ML.

Loose, blue-gray SANDY SILT with GRAVEL; sMLg.

Loose, gray SILT; ML.

Loose, gray SANDY SILT; sML.

Medium-dense, gray poorly graded SAND; SP.

Size Distribution

Other Tests

Moisture % 40302010

Blows per foot

Salinity ppt

Bl ow s/ in

Graphic LogSymbolSoil ClassificationSa m pl e

Re co ve ry

Sa m pl e

Ty pe

Dr ill

M et ho d

( f t)

De pt h

Logged By: KL, DJR Reviewed By: TM Review Date: 7/6/2023Longitude: 151.07094°W

Horizontal Datum: WGS 84 Latitude: 60.46347°N05Project Phase:

211147Project Number:

Headquarters Lake Educational AreaProject:

LOG OF BH-2

11Page: ofJBDriller:

6610DTDrill Equipment:

GeoTekDrilling Contractor:

4/25/2023 Drill Start:

US Fish & Wildlife ServiceClient:

30.5Borehole terminated at

B-1 JULY 2023

Appendix B. Summary of Lab and Field Characteristics

B o re h o le

Sam p le

Fro m

T o

Sam p le M e th o d

Liq u id Lim it (%

P lastic Lim it (%

G rave l

San d

Fin e s*

Gradation (%) M ax P article

Size (in

Salin ity (p p t)

M o istu re

P article

Sh ap e

A n gu larity

O th e r T e sts*

Lab o rato ry

C lassificatio n

Summary of Sample Characteristics

Project: Headquarters Lake Educational Area

Project #: 211147

Client: US Fish & Wildlife Service

BH-1 1 0 0.5 793PTSh

BH-1 2 3 4 490OLGR

BH-1 3 5.5 6.5 570OLSh

BH-1 4 8 8.5 508PTSh

BH-1 5 9 9.5 62.9 29sMLSh

BH-1 6 10.5 11.5 20sMLSh

BH-1 7 15.5 16.5 23 19 25MLSh

BH-1 8 20.5 21.5 35MLsSh

BH-1 9 25.5 26.5 25.3 1/2 11 SR-SAgMLsSh

BH-1 10 31 31.5 7.0 1/2 16 SR-SASP-SMSh

BH-1 11 35 35.5 21.5 68.7 9.0 1.5 15 SR(SW-SM)gSh

BH-2 1 0 1 387PTGR

BH-2 2 4.5 5 395OLGR

BH-2 3 10 10.5 20 16 18MLSh

BH-2 4 14 14.5 30sMLgSh

BH-2 5 15 15.5 79.0 1/2 29 SR-SAMLSh

BH-2 6 19.5 20.5 37 27 33MLSh

BH-2 7 25 25.5 16 15 55.9 3/8 17 SR-SAsMLSh

BH-2 8 29.5 30.5 1.6 25SPSh

19 samples

*Fines type and content estimated with ASTM D2488 when ASTM D422 or D4318 were not performed **Other tests: DEN = Bulk Density, SPG = Specific Gravity, HYD = Hydrometer, CONSL = Consolidation, UCS = Unconfined Compression Strength, TRIAX = Triaxial

C-1 JULY 2023

Appendix C. Grain Size Distribution Plots 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: Headquarters Lake Educational Area

Project #: 211147

Client: US Fish & Wildlife Service

75.70.49.868.721.535.535BH-1 (SW-SM)g11

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

D-1 JULY 2023

Appendix D. Moisture Content by Depth Graph

D-2 JULY 2023

Figure D-1. Moisture Content by Depth

E-1 JULY 2023

Appendix E. SPT Blowcount Correction Plot

E-2 JULY 2023

Figure E-1. SPT Corrected Blowcount

F-1 JULY 2023

Appendix F. Atterberg Limit Plots

Atterberg Test Results

Project: Headquarters Lake Educational Area

Project #: 211147

Client: US Fish & Wildlife Service

PILLMoisture %ToFromBorehole Sample # PL Soil Type

3.522.916.515.5BH-1 25.10%7 19.35 ML

4.019.910.510BH-2 17.93%3 15.89 ML

9.436.520.519.5BH-2 33.01%6 27.15 ML

1.416.025.525BH-2 16.62%7 14.66 ML

G-1 JULY 2023

Appendix G. Site-Specific Seismic and Liquefaction Analysis

G-2 JULY 2023

Figure G-1. Keen Eye Liquefaction Analysis

Spoon OD (in.) = 3.0 ER = 70 % Return Period = 2475 years Cohesive ONLY <-only use this for clay Cohesionless ONLY Spoon ID (in.) = 2.5 Dia = 110 (65-115, 150 or 200) mm Mw = 9.2 Chs = W H (ODspt^2 - IDspt^2) Chs = W H (ODspt^3 - IDspt^3)

Hammer weight (lb) = 340 Sampler Lined (Y/N) = N MSF = 0.63 Wspt Hspt (OD^2 - ID^2) Wspt Hspt (OD^3 - ID^3) Hammer Drop (in.) = 30 PGA = 0.50 g Chs = Rc(spt)/Rc = 1.86 Chs = Rs(spt)/Rs 1.15

SPT Spoon OD (in.) = 2.0 Rc(clay)= OD^2 - ID^2 Rs(sand)= OD^3 - ID^3 SPT Spoon ID (in.) = 1.375 WD = 14 ft ∆σ: 0 psf 12 W H 144 W H

SPT Hammer weight (lb) = 140 γw= 64 pcf ∆σ': 0 psf SPT Hammer Drop (in.) = 30 Offshore No Thickness: 0 ft

Water Height ft ∆SPT 0 bpf Ground Elev 0 ft

Borehole = BH-1 MCE Fines overburden sampler sample energy rod length borehole Potentially

Elevation Depth Soil γbulk NField Content σv σ'v factor size factor liner factor factor factor dia. factor N60 (N1)60 Dr α β (N1)60 CS rd CSR CRR7.5 Ks CRR FSLIQ Liquefiable?

(ft) (ft) Type (pcf) (blows/ft) (%) (psf) (psf) CN CHS Cs CE CR CB (blows/ft) (blows/ft) % (blows/ft) -0.1 0.1 Silt 75 0 50 8 7.5 1.70 1.15 1.10 1.17 0.75 1.00 0 0 30 5.000 1.20 5 0.9998 0.325 0.07 5.434 0.25 0.76 No PT -2.5 2.5 Silt 75 0 50 188 187.5 1.70 1.15 1.10 1.17 0.75 1.00 0 0 30 5.000 1.20 5 0.9942 0.323 0.07 2.069 0.09 0.29 No PT -5 5 Silt 75 0 50 375 375.0 1.70 1.15 1.10 1.17 0.75 1.00 0 0 30 5.000 1.20 5 0.9883 0.321 0.07 1.681 0.08 0.24 No PT

-7.5 7.5 Silt 75 0 50 563 562.5 1.70 1.15 1.10 1.17 0.75 1.00 0 0 30 5.000 1.20 5 0.9825 0.319 0.07 1.488 0.07 0.21 No PT -10 10 Silt 90 6 50 788 787.5 1.64 1.15 1.10 1.17 0.75 1.00 7 11 48 5.000 1.20 18 0.9767 0.317 0.19 1.345 0.16 0.52 No sML -15 15 Silt 95 9 40 1,263 1198.5 1.33 1.15 1.10 1.17 0.85 1.00 11 15 54 5.000 1.20 23 0.9650 0.330 0.26 1.186 0.19 0.59 Yes ML -20 20 Silt 85 2 50 1,688 1303.5 1.27 1.15 1.10 1.17 0.95 1.00 3 4 35 5.000 1.20 9 0.9534 0.401 0.11 1.156 0.08 0.20 Yes MLs -25 25 Silt 100 13 50 2,188 1483.5 1.19 1.15 1.13 1.17 0.95 1.00 19 22 64 5.000 1.20 32 0.9417 0.451 2.00 1.112 1.41 2.00 No gMLs -30 30 Sand 125 48 5 2,813 1788.5 1.09 1.15 1.30 1.17 1.00 1.00 84 91 90 0.000 1.00 91 0.9300 0.475 2.00 1.052 1.33 2.00 No SW-SM -34 34 Sand 120 24 5 3,293 2012.5 1.03 1.15 1.24 1.17 1.00 1.00 40 41 73 0.000 1.00 41 0.8973 0.477 2.00 1.015 1.29 2.00 No (SP-SM)g

Legend γlim Fα γmax εv Settlement Dr εv Settlement (N1)60cs CSR εv Settlement Depth Depth of sample (ft) (%) (%) (%) (inches) FSLIQ % (%) (inches) (blows/ft) (%) (inches)

Soil Type Dominate soil type: Gravel, Sand, Silt, or Clay 0.500 0.95 0.500 5.26% 0.000 0.76 30 5.50% 0.000 5 0.325 5.57% 0.000 γbulk Bulk unit weight of soil (pcf) 0.500 0.95 0.500 5.26% 0.000 0.29 30 5.50% 0.000 5 0.323 5.57% 0.000

NField Uncorrected SPT field blowcount 0.500 0.95 0.500 5.26% 0.000 0.24 30 5.50% 0.000 5 0.321 5.57% 0.000 Fines Content Approximate percent of fines (minus No. 200) 0.500 0.95 0.500 5.26% 0.000 0.21 30 5.50% 0.000 5 0.319 5.57% 0.000 σv Total vertical stress 0.196 0.61 0.196 2.50% 0.000 0.52 48 3.68% 0.000 18 0.317 2.57% 0.000 σ'v Effective vertical stress 0.112 0.35 0.112 2.04% 0.000 0.59 54 3.17% 0.000 23 0.330 2.23% 0.000 ER Energy ratio for the SPT hammer system (%) 0.500 0.93 0.500 3.90% 2.337 0.20 35 0.00% 0.000 9 0.401 3.84% 2.303 WD Groundwater level below ground surface (ft) 0.035 -0.22 0.000 0.00% 0.000 2.00 64 0.00% 0.000 32 0.451 0.00% 0.000 CN Overburden correction for SPT blowcount 0.000 -5.24 0.000 0.00% 0.000 2.00 90 0.00% 0.000 91 0.475 0.00% 0.000 CE Energy correction for SPT blowcount (ER/60) 0.007 -0.88 0.000 0.00% 0.000 2.00 73 0.00% 0.000 41 0.477 0.00% 0.000 CB Borehole diameter correction for SPT blowcount CR Rod length correction for SPT blowcount CS Sampler correction for SPT blowcount CHS Sampler and Hammer correction for SPT blowcount (Burmister 1948) Dia Borehole diameter (mm)

Sampler Lined Sampler lined or unlined GSE Ground surface elevation (feet) (N1)60 SPT blowcount corrected for all factors (CN Liao and RV Whitman 1986)

(N1)60 CS SPT blowcount corrected for fines content Dr Relative Density, % (max of 90%) rd Stress reduction factor S = 2.34 in S = 0.00 in S = 2.30 in

CSR Cyclic Stress Ratio (seismic demand) CRR7.5 Cyclic Resistance Ratio (soil capacity) normalized for a Mw = 7.5 earthquake References:

MSF Magnitude scaling factor 1 Youd et al., (2001), Liquefaction Resistance of Soils: Summary Report from 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils FSLIQ Factor of Safety against liquefaction being triggered (NOT APPLICABLE IF SOIL TYPE IS A CLAY) 2 Evaluation of Settlements in Sand Deposits Following Earthquakes, Ishihara, K. and Yoshimine, M., Soils and Foundations, Vol.32, No.1, pp.173-188, 1992.

Mw: Earthquake moment magnitude 3 Evaluation of Settlements in Sand Due to Earthquake Shaking, Tokimatsu, K. and Seed, H.B., Journal of Geotechnical Engineering, Vol. 113, No. 8, pp. 861-878, 1987.

PGA Maximum horizontal acceleration at ground surface (g) 4 Earthquake-Induced Settlements in Saturated Sandy Soils, Lee, C.Y., ARPN Journal of Engineering and Applied Sciences, Vol. 2, No. 4, pp. 6-13, 2007

Total Settlement Total Settlement Total Settlement

LIQUEFACTION SETTLEMENT

Idriss and Boulanger, 20081 Ishihara, 19922 Tokimatsu and Seed, 19873 as modified by Lee, 20074

SPT BLOW COUNT CORRECTIONS AND LIQUEFACTION POTENTIAL1

Input Parameters:

Hammer / Split Spoon Earthquake Motion Sample Size Correction Factor Equations From Fang's Foundation Engineering Handbook, 2nd Ed

Groundwater

211147-05

PND ENGINEERS, INC.

CALC'D BY: DJR

Keen Eye Headquarters Lake TrailDATE: 5/5/2023

FILE NAME. Liquefaction Potential CHECK: TM

DATE: 7/6/2023PROJECT NUMBER: BH-1 MCE

http://geot.civil.metro-u.ac.jp/%7Emy/publications/settlement/p00.html

Spoon OD (in.) = 3.0 ER = 70 % Return Period = 2475 years Cohesive ONLY <-only use this for clay Cohesionless ONLY Spoon ID (in.) = 2.5 Dia = 110 (65-115, 150 or 200) mm Mw = 9.2 Chs = W H (ODspt^2 - IDspt^2) Chs = W H (ODspt^3 - IDspt^3)

Hammer weight (lb) = 340 Sampler Lined (Y/N) = N MSF = 0.63 Wspt Hspt (OD^2 - ID^2) Wspt Hspt (OD^3 - ID^3) Hammer Drop (in.) = 30 PGA = 0.50 g Chs = Rc(spt)/Rc = 1.86 Chs = Rs(spt)/Rs 1.15

SPT Spoon OD (in.) = 2.0 Rc(clay)= OD^2 - ID^2 Rs(sand)= OD^3 - ID^3 SPT Spoon ID (in.) = 1.375 WD = 14 ft ∆σ: 0 psf 12 W H 144 W H

SPT Hammer weight (lb) = 140 γw= 64 pcf ∆σ': 0 psf SPT Hammer Drop (in.) = 30 Offshore No Thickness: 0 ft

Water Height ft ∆SPT 0 bpf Ground Elev 0 ft

Borehole = BH-2 MCE Fines overburden sampler sample energy rod length borehole Potentially

Elevation Depth Soil γbulk NField Content σv σ'v factor size factor liner factor factor factor dia. factor N60 (N1)60 Dr α β (N1)60 CS rd CSR CRR7.5 Ks CRR FSLIQ Liquefiable?

(ft) (ft) Type (pcf) (blows/ft) (%) (psf) (psf) CN CHS Cs CE CR CB (blows/ft) (blows/ft) % (blows/ft) -4 4 Silt 75 0 50 300 300 1.70 1.15 1.10 1.17 0.75 1.00 0 0 30 5.000 1.20 5 0.9907 0.322 0.07 1.797 0.08 0.25 No PT -14 14 Silt 85 2 100 1,150 1,150 1.36 1.15 1.10 1.17 0.85 1.00 3 3 34 5.000 1.20 9 0.9674 0.314 0.11 1.201 0.08 0.25 Yes ML -19 19 Silt 90 5 100 1,600 1,280 1.29 1.15 1.10 1.17 0.85 1.00 6 8 43 5.000 1.20 15 0.9557 0.388 0.16 1.163 0.12 0.30 Yes ML -24 24 Silt 85 3 100 2,025 1,385 1.24 1.15 1.10 1.17 0.95 1.00 4 5 38 5.000 1.20 11 0.9440 0.449 0.12 1.136 0.09 0.20 Yes sML -29 29 Sand 120 10 5 2,625 1,665 1.13 1.15 1.10 1.17 0.95 1.00 14 16 45 0.000 1.00 16 0.9324 0.478 0.17 1.075 0.11 0.24 Yes SP

Legend γlim Fα γmax εv Settlement Dr εv Settlement (N1)60cs CSR εv Settlement Depth Depth of sample (ft) (%) (%) (%) (inches) FSLIQ % (%) (inches) (blows/ft) (%) (inches)

Soil Type Dominate soil type: Gravel, Sand, Silt, or Clay 0.500 0.95 0.500 5.26% 0.000 0.25 30 5.50% 0.000 5 0.322 5.57% 0.000 γbulk Bulk unit weight of soil (pcf) 0.500 0.93 0.500 3.94% 0.000 0.25 34 5.08% 0.000 9 0.314 3.89% 0.000

NField Uncorrected SPT field blowcount 0.284 0.77 0.284 2.92% 1.749 0.30 43 4.15% 2.492 15 0.388 2.92% 1.749 Fines Content Approximate percent of fines (minus No. 200) 0.412 0.88 0.412 3.48% 2.088 0.20 38 4.70% 2.817 11 0.449 3.42% 2.053 σv Total vertical stress 0.251 0.72 0.251 2.76% -3.977 0.24 45 3.99% 2.396 16 0.478 2.79% 1.672 σ'v Effective vertical stress ER Energy ratio for the SPT hammer system (%) WD Groundwater level below ground surface (ft) CN Overburden correction for SPT blowcount CE Energy correction for SPT blowcount (ER/60) CB Borehole diameter correction for SPT blowcount CR Rod length correction for SPT blowcount CS Sampler correction for SPT blowcount CHS Sampler and Hammer correction for SPT blowcount (Burmister 1948) Dia Borehole diameter (mm)

Sampler Lined Sampler lined or unlined GSE Ground surface elevation (feet) (N1)60 SPT blowcount corrected for all factors (CN Liao and RV Whitman 1986)

(N1)60 CS SPT blowcount corrected for fines content Dr Relative Density, % (max of 90%) rd Stress reduction factor S = -0.14 in S = 7.71 in S = 5.47 in

CSR Cyclic Stress Ratio (seismic demand) CRR7.5 Cyclic Resistance Ratio (soil capacity) normalized for a Mw = 7.5 earthquake References:

MSF Magnitude scaling factor 1 Youd et al., (2001), Liquefaction Resistance of Soils: Summary Report from 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils FSLIQ Factor of Safety against liquefaction being triggered (NOT APPLICABLE IF SOIL TYPE IS A CLAY) 2 Evaluation of Settlements in Sand Deposits Following Earthquakes, Ishihara, K. and Yoshimine, M., Soils and Foundations, Vol.32, No.1, pp.173-188, 1992.

Mw: Earthquake moment magnitude 3 Evaluation of Settlements in Sand Due to Earthquake Shaking, Tokimatsu, K. and Seed, H.B., Journal of Geotechnical Engineering, Vol. 113, No. 8, pp. 861-878, 1987.

PGA Maximum horizontal acceleration at ground surface (g) 4 Earthquake-Induced Settlements in Saturated Sandy Soils, Lee, C.Y., ARPN Journal of Engineering and Applied Sciences, Vol. 2, No. 4, pp. 6-13, 2007

Total Settlement Total Settlement Total Settlement

LIQUEFACTION SETTLEMENT

Idriss and Boulanger, 20081 Ishihara, 19922 Tokimatsu and Seed, 19873 as modified by Lee, 20074

SPT BLOW COUNT CORRECTIONS AND LIQUEFACTION POTENTIAL1

Input Parameters:

Hammer / Split Spoon Earthquake Motion Sample Size Correction Factor Equations From Fang's Foundation Engineering Handbook, 2nd Ed

Groundwater

211147-05

PND ENGINEERS, INC.

CALC'D BY: DJR

Keen Eye Headquarters Lake TrailDATE: 5/5/2023

FILE NAME. Liquefaction Potential CHECK: TM

DATE: 7/6/2023PROJECT NUMBER: BH-2 MCE

http://geot.civil.metro-u.ac.jp/%7Emy/publications/settlement/p00.html

3.3 Idealized Soil Profile