Attachment7_GeotechnicalReport.pdf

SUBMITTED TO:

Design Alaska Inc.

601 College Road Fairbanks, AK 99701

BY:

Shannon & Wilson 2355 Hill Road Fairbanks, AK 99709

907-479-0600 www.shannonwilson.com

GEOTECHNICAL FINDINGS REPORT

White Mountains Recreation Area Borrow Sites Exploration - Site 5

NOME CREEK ROAD, ALASKA

March 20, 2023 Shannon & Wilson No: 107285-004

White Mountains Recreation Area Borrow Sites Exploration - Site 5 Geotechnical Findings Report

107285-004 March 20, 2023

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Submitted To: Design Alaska Inc.

601 College Road Fairbanks, AK 99701 Attn: Jeff Putnam, PE

Subject: GEOTECHNICAL FINDINGS REPORT, WHITE MOUNTAINS RECREATION

AREA BORROW SITES EXPLORATION - SITE 5, NOME CREEK ROAD,

ALASKA

Shannon & Wilson prepared this report and participated in this project as a subconsultant to Design Alaska, Inc. Our scope of services was specified in Agreement Amendment dated August 20, 2022. This report presents our findings and was prepared by the undersigned.

Sincerely, SHANNON & WILSON

Wendy Presler, P.E.

Senior Associate / Geotechnical Engineer

Wendy Presler 2023.03.20 10:42:44 -08'00'

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CONTENTS

1 Introduction

2 Field and Laboratory Studies

2.1 Field Exploration and Methods

2.1.1 Geotechnical Test Pits

2.2 Laboratory Testing

3 Site Conditions

4 Closure

5 References

Exhibits Exhibit 2-1: Aggregate Quality Test Results

Figures Figure 1: Material Site 5 Test Pit Locations

Appendices Appendix A: Soil Classification Appendix B: Laboratory Test Results Important Information

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ACRONYMS

ADOT Alaska Department of Transportation & Public Facilities ASTM ASTM International ATM Alaska test method bgs below ground surface MS material site

107285-004 March 20, 2023

1 INTRODUCTION

This report was prepared for the Nome Creek Road project in the White Mountains Recreation Area. This report presents our findings from the material site (MS) explorations, laboratory test results, and discussion of the identified material source.

The project includes development of a borrow source to provide suitable aggregate for construction and for future maintenance.

After our completed findings report, and March 8, 2023, meeting, we understand you have chosen MS 5 as the preferred borrow site. This report presents the findings from MS 5.

2 FIELD AND LABORATORY STUDIES

The field explorations for Site 5 consisted of 6 test pits. Site 5 and the approximate test pit locations are presented in Figure 1.

At each test pit we collected representative samples of gravel and cobble material and combined materials from all six test pits to create a combined sample. The combined sample was transported back to our laboratory for aggregate quality testing. We split the bulk sample into two subsamples and conducted LA Abrasion, Degradation, and Sulfate Soundness testing on the subsamples, designated 5-1 and 5-2.

2.1 Field Exploration and Methods

The test pits were advanced by our subcontractor using a Doosan DX 225 LC excavator.

2.1.1 Geotechnical Test Pits

We advanced test pits at MS 5 on August 2, 2022. The test pits advanced within the identified source areas were advanced to depths ranging from 8 feet below the ground surface (bgs) to 11 feet bgs.

Nathan Adamczak, an experienced geotechnical staff member with our firm, observed the test pitting operations, created a test pit log for each test pit, and collected the material samples for aggregate quality testing in our laboratory. Material samples were recorded and transported to our Fairbanks, Alaska laboratory. The test pits were backfilled with the excavated material after completion of each pit.

107285-004 March 20, 2023

Shannon & Wilson uses a soil identification system modified from the Unified Soil Classification System. Soil descriptions are based on visual-manual procedures consistent with ASTM International (ASTM) D2488 Standard Practice for Description and Identification of Soils (Visual-Manual Procedure) and laboratory testing procedures consistent with ASTM D2487 Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System).

Soil and excavation observations are included in the test pit logs presented in Appendix A.

Our observations are specific to the locations, depths, and dates noted on the logs, and may not be applicable to all areas of the site.

2.2 Laboratory Testing

The aggregate quality testing consisted of the following test methods: LA abrasion consistent with ASTM C131 Standard Test Method for Resistance to Degradation of Small-size Coarse Aggregate by Abrasion and Impact in the Los Angeles Machine, sulfate soundness consistent with ASTM C88 Standard Test Method for Soundness of Aggregates by use of Sodium Sulfate or Magnesium Sulfate, and degradation testing consistent with Alaska test method (ATM) 313 Degradation Value of Aggregates. The LA Abrasion test is used to characterize the aggregate toughness and abrasion resistance, the Degradation test characterizes the aggregate durability and relative resistance to produce clay like fines during a prescribed abrasion process in water, and the Sulfate Soundness test characterizes the aggregate resistance to breakdown from weathering during wetting/drying and freezing/thawing.

Test results are presented in Appendix B and summarized in the following table. The table also includes Alaska Department of Transportation and Public Facilities (ADOT) specification limits for Base Course and Surface Course aggregates for comparison purposes.

Exhibit 2-1: Aggregate Quality Test Results

Sample ID (Site-Sample)

LA Abrasion Percent Loss Degradation Value

Sulfate Soundness Percent Loss

5-1 40 81 1

5-2 39 79 0

ADOT Base Course Specifications

50, max. 45, min. 9, max.

ADOT Surface Course Specifications

45, max. 45, min. 9, max.

107285-004 March 20, 2023

3 SITE CONDITIONS

The area originally identified as MS 5 was approximately 38 acres. Based on access, vegetation, and topography information collecting during our site explorations, and using subsurface data collected, the area was reduced to a total area just under 28 acres. Surface conditions consisted of tundra with sparse black spruce and low-lying areas of saturated tundra and grasses on the north side of the site. The surface conditions at the west end of the site included tundra with dense tall black spruce and white spruce. The east side of the site also consisted of tundra with tall black spruce, white spruce, and alder.

Subsurface conditions at MS 5 consisted of frozen silt and silty gravel to the depth explored in areas with tundra and sparse black spruce. In an area of tall white spruce on the west side of the site we observed approximately two feet of silty material underlain by approximately five feet to six feet of gravel with cobbles. In an area of tall white spruce, black spruce, and alder on the east side of the site we observed approximately two feet to three feet of silty material underlain by approximately six feet to eight feet of gravel and cobble.

4 CLOSURE

Our interpretations, analyses, conclusions, and recommendations are based on:

The limitations of our approved scope, schedule, and budget.

Our understanding of the project and information collected during our explorations, as well as information provided by the Owner and our client.

Our previous experience near the project site, and on similar projects in the area.

This report was prepared for the exclusive use of Design Alaska, Inc. for specific application to the design and construction of the White Mountains Recreation Area Access Improvements project. This report is not intended to be used or relied upon for any other purpose. Please review "Important Information about your Geotechnical Report", which can be found at the end of this report.

5 REFERENCES

ASTM International, 2017, Standard practice for description and identification of soils

(visual/manual procedure), D2488-17e1: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, 13 p., available: www.astm.org.

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ASTM International, 2018, Standard test method for soundness of aggregates by use of sodium sulfate or magnesium sulfate, C88-18: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.02, concrete and aggregates, 6 p., available: www.astm.org.

ASTM International, 2020, Standard practice for classification of soils for engineering purposes (unified soil classification system), D2487-17e1: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, 10 p., available: www.astm.org.

ASTM International, 2020, Standard test method for resistance to degradation of small-size coarse aggregate by abrasion and impact in the Los Angeles machine, C131-20:

West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.02, concrete and aggregates, 5 p., available: www.astm.org.

ASTM International, 2021, Standard test methods for laboratory determination of density (unit weight) of soil specimens, D7263-21: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.09, soil and rock (I): D5877-latest, 7 p., available: www.astm.org.

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Maxar Technologies Inc., Alaska Geospatial Office, USGS

0 600 1,200

Feet

Borrow Sites Exploration White Mountains Recreation Area

Nome Creek Road, Alaska

MATERIAL SITE 5

TEST PIT LOCATIONS

Figure 107285

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Possible Material Site

Map adapted from aerial and satellite imagery provided through the Alaska Department of Natural Resources.

http://gis.dnr.alaska.gov/terrapixel/cubeserv/OIM_BDL?

Nome Creek Road

10.7 Acres 2.9 Acres

14.3 Acres

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Appendix A: Soil Classification

Appendix A

Soil Classification

CONTENTS

Table A1 Frozen Soil Classification

Figure A1 Soil Description and Log Key

Figures A2 through A6 Logs of Test Pits

Table A1 - Summary of Frozen Soil Classification System Designation

No excess ice Nbn

Excess ice Nbe

Vx

Vc

Vs

Vr

Vu

ICE + soil type

ICE

NOTE:

Based on Linell, K.A. and C.W. Kaplar, 1966, Description and Classification of Frozen Soils, U.S. Army Cold Regions Research Engineering Laboratory, Technical Report 150, Hanover, N.H

Nf

Well bonded – Soil particles strongly held together by ice

Ice greater than 1 inch thick Ice with soil inclusions

Ice without soil inclusions

Uniformly distributed ice

Description

Segregated ice is visible by eye (less than 1 inch thick)

Individual ice crystals or inclusions

Ice coatings on soil particles

Stratified or distinctly oriented ice formations

Randomly or irregularly oriented ice formations

Segregated ice is not visible by eye

Friable, poorly bonded Material is easily broken up

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Appendix B: Laboratory Test Results

Appendix B

Laboratory Test Results

CONTENTS

LA Abrasion Test Results

Degradation Test Results

Sulfate Soundness Test Results

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Important Information About Your Geotechnical Report

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CONSULTING SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND FOR

SPECIFIC CLIENTS.

Consultants prepare reports to meet the specific needs of specific individuals. A report prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer.

Unless indicated otherwise, your consultant prepared your report expressly for you and expressly for the purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the consultant. No party should apply this report for any purpose other than that originally contemplated without first conferring with the consultant.

THE CONSULTANT’S REPORT IS BASED ON PROJECT-SPECIFIC FACTORS.

A geotechnical/environmental report is based on a subsurface exploration plan designed to consider a unique set of project-specific factors. Depending on the project, these may include the general nature of the structure and property involved; its size and configuration; its historical use and practice; the location of the structure on the site and its orientation; other improvements such as access roads, parking lots, and underground utilities; and the additional risk created by scope-of-service limitations imposed by the client. To help avoid costly problems, ask the consultant to evaluate how any factors that change subsequent to the date of the report may affect the recommendations. Unless your consultant indicates otherwise, your report should not be used

(1) when the nature of the proposed project is changed (for example, if an office building will be erected instead of a parking garage, or if a refrigerated warehouse will be built instead of an unrefrigerated one, or chemicals are discovered on or near the site); (2) when the size, elevation, or configuration of the proposed project is altered; (3) when the location or orientation of the proposed project is modified; (4) when there is a change of ownership; or (5) for application to an adjacent site.

Consultants cannot accept responsibility for problems that may occur if they are not consulted after factors that were considered in the development of the report have changed.

SUBSURFACE CONDITIONS CAN CHANGE.

Subsurface conditions may be affected as a result of natural processes or human activity. Because a geotechnical/environmental report is based on conditions that existed at the time of subsurface exploration, construction decisions should not be based on a report whose adequacy may have been affected by time. Ask the consultant to advise if additional tests are desirable before construction starts; for example, groundwater conditions commonly vary seasonally.

Construction operations at or adjacent to the site and natural events such as floods, earthquakes, or groundwater fluctuations may also affect subsurface conditions and, thus, the continuing adequacy of a geotechnical/environmental report. The consultant should be kept apprised of any such events and should be consulted to determine if additional tests are necessary.

MOST RECOMMENDATIONS ARE PROFESSIONAL JUDGMENTS.

Site exploration and testing identifies actual surface and subsurface conditions only at those points where samples are taken. The data were extrapolated by your consultant, who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates. Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations, you and your consultant can work together to help reduce their impacts. Retaining

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N your consultant to observe subsurface construction operations can be particularly beneficial in this respect.

A REPORT’S CONCLUSIONS ARE PRELIMINARY.

The conclusions contained in your consultant’s report are preliminary, because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions throughout a site. Actual subsurface conditions can be discerned only during earthwork; therefore, you should retain your consultant to observe actual conditions and to provide conclusions. Only the consultant who prepared the report is fully familiar with the background information needed to determine whether or not the report’s recommendations based on those conclusions are valid and whether or not the contractor is abiding by applicable recommendations.

The consultant who developed your report cannot assume responsibility or liability for the adequacy of the report’s recommendations if another party is retained to observe construction.

THE CONSULTANT’S REPORT IS SUBJECT TO MISINTERPRETATION.

Costly problems can occur when other design professionals develop their plans based on misinterpretation of a geotechnical/environmental report. To help avoid these problems, the consultant should be retained to work with other project design professionals to explain relevant geotechnical, geological, hydrogeological, and environmental findings, and to review the adequacy of their plans and specifications relative to these issues.

BORING LOGS AND/OR MONITORING WELL DATA SHOULD NOT BE SEPARATED

FROM THE REPORT.

Final boring logs developed by the consultant are based upon interpretation of field logs (assembled by site personnel), field test results, and laboratory and/or office evaluation of field samples and data.

Only final boring logs and data are customarily included in geotechnical/environmental reports.

These final logs should not, under any circumstances, be redrawn for inclusion in architectural or other design drawings, because drafters may commit errors or omissions in the transfer process.

To reduce the likelihood of boring log or monitoring well misinterpretation, contractors should be given ready access to the complete geotechnical engineering/environmental report prepared or authorized for their use. If access is provided only to the report prepared for you, you should advise contractors of the report’s limitations, assuming that a contractor was not one of the specific persons for whom the report was prepared, and that developing construction cost estimates was not one of the specific purposes for which it was prepared. While a contractor may gain important knowledge from a report prepared for another party, the contractor should discuss the report with your consultant and perform the additional or alternative work believed necessary to obtain the data specifically appropriate for construction cost estimating purposes. Some clients hold the mistaken impression that simply disclaiming responsibility for the accuracy of subsurface information always insulates them from attendant liability. Providing the best available information to contractors helps prevent costly construction problems and the adversarial attitudes that aggravate them to a disproportionate scale.

READ RESPONSIBILITY CLAUSES CLOSELY.

Because geotechnical/environmental engineering is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims

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N being lodged against consultants. To help prevent this problem, consultants have developed a number of clauses for use in their contracts, reports, and other documents. These responsibility clauses are not exculpatory clauses designed to transfer the consultant’s liabilities to other parties;

rather, they are definitive clauses that identify where the consultant’s responsibilities begin and end.

Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your report, and you are encouraged to read them closely. Your consultant will be pleased to give full and frank answers to your questions.

The preceding paragraphs are based on information provided by the ASFE/Association of Engineering Firms Practicing in the Geosciences, Silver Spring, Maryland