B08_Solicitation_Attach_4_Geotech_Report_.pdf

Geotechnical ● Materials Forensic ● Environmental

Building Technology Petrography/Chemistry

American Engineering Testing 1745 Samco Road Rapid City, South Dakota 57702 TeamAET.com • 605.388.0029

Report of Geotechnical Exploration Proposed Conata Picnic Area Reconstruction Badlands National Park, South Dakota

AET Project No. P-0015784

Date:

September 12, 2022

Prepared for:

7 Generations Architecture & Engineering 600 E Michigan Avenue Suite B Kalamazoo, MI 49007

Page i

1745 Samco Road | Rapid City, SD 57702 Phone (605) 388-0029 | teamAET.com | AA/EEO

This document shall not be reproduced, except in full, without written approval from American Engineering Testing, Inc.

Kalmazoo, MI 49007

Attn: Mr. Christopher Clark ccork@7genae.com

RE: Report of Geotechnical Exploration Proposed Conata Picnic Area Reconstruction Badlands National Park, South Dakota AET Project No. P-0015784

Dear Mr. Clark, American Engineering Testing, Inc. (AET) is pleased to present the results of our subsurface exploration program and geotechnical engineering review for the above referenced project in Badlands National Park, South Dakota. These services were performed in general accordance with our proposal to you dated June 8, 2022, and written authorization to proceed provided on August 12, 2022. We are submitting one (1) electronic copy of the report to you.

Please contact me if you have any questions about the report. I can also be contacted to arrange observation and testing services during construction of the project.

Sincerely, American Engineering Testing, Inc.

James Reed, PG Geologist II jreed@teamaet.com Phone: (605) 388-0029

Conata Picnic Area Reconstruction – Badlands National Park, South Dakota

Copyright 2022 American Engineering Testing, Inc.

All Rights Reserved

Unauthorized use or copying of this document is strictly prohibited by anyone other than the client for the specific project.

Page ii

SIGNATURE PAGE

Prepared for: Prepared by:

7 Generations Architecture & Engineering American Engineering Testing, Inc.

600 E Michigan Avenue Suite B 1745 Samco Road Kalmazoo, MI 49007 Rapid City, South Dakota 57702

(605) 388-0029 www.teamAET.com

Attn: Mr. Christopher Clark

Authored by: Reviewed by:

James Reed, PG Walt Feeger, PE Geologist II Senior Geotechnical Engineer

Page iii

TABLE OF CONTENTS

Transmittal Letter ............................................................................................................. i Signature Page ................................................................................................................ ii

1.0 INTRODUCTION

2.0 SCOPE OF SERVICES

3.0 PROJECT INFORMATION

4.0 SUBSURFACE EXPLORATION AND TESTING

4.1 Field Exploration Program

4.2 Laboratory Testing

5.0 SITE CONDITIONS

5.1 Surface Observations

5.2 Subsurface Soils/Geology

5.3 Groundwater

6.0 RECOMMENDATIONS

6.1 Discussion

6.2 Site Preparation

6.3 Monolithic Slab-On-Grade Foundation Recommendations

6.4 Backfill Considerations

6.5 Asphalt Pavement

6.6 Pavement Maintenance

7.0 CONSTRUCTION CONSIDERATIONS

7.1 Potential Difficulties

7.2 Excavation Backsloping

7.3 Observation and Testing

8.0 LIMITATIONS

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TABLE OF CONTENTS

APPENDIX A

Geotechnical Field Exploration and Testing Boring Log Notes Unified Soil Classification System Figure 1: Site Location Map Figure 2: Boring Location Map Subsurface Boring Logs Moisture-Density Relationship (Proctor) Test Report California Bearing Ratio (CBR) Test Report

APPENDIX B

Geotechnical Report Limitations and Guidelines for Use

1.0 INTRODUCTION

We understand a new pavilion and road reconstruction is planned for the Conata Picnic Area within Badlands National Park, South Dakota. Please refer to Figure 1: Site Location Map within Appendix A for the location of the site. To assist with the planning and design, American Engineering Testing, Inc. (AET) has been authorized to conduct a subsurface exploration program at the site, conduct soil laboratory testing, and perform a geotechnical engineering review for the project. This report presents the results of the above services and provides our engineering recommendations based on this data.

2.0 SCOPE OF SERVICES

AET's services were performed in general accordance with our proposal dated June 8.

The authorized scope consists of the following:

Four (4) Standard Penetration Test (SPT) borings: three (3) along the existing access road to depths of approximately 5 feet below existing grade and one within the area of the proposed pavilion to approximately 15 feet below existing grade.

Soil laboratory testing.

Geotechnical engineering analysis based on the gained data and preparation of this report.

These services are intended for geotechnical purposes only. The scope is not intended to explore for the presence or extent of environmental contamination in the soil or groundwater.

3.0 PROJECT INFORMATION

Based on the information provided by Mr. John Witte of WBK Engineering, via email April 18, 2022, the project will consist of the design of an approximate 200 square-foot outdoor classroom/covered picnic shelter located at the existing Conata Picnic Area in Badlands National Park. We understand the picnic shelter will consist of a post and beam structure with shallow frost-depth concrete pier footings for the posts and concrete slab-on-grade floor. The project will also include reconstruction of the access road into the picnic area, replacement of culverts, realignment of the drainage ditches and new curb and gutter.

The roadway length is approximately 1,200 linear feet, west of Conata Basin Road.

The previously stated information represents our understanding of the proposed construction. This information is an integral part of our engineering review. It is important that you contact us if there are changes from that described so that we can evaluate whether modifications to our recommendations are appropriate.

4.0 SUBSURFACE EXPLORATION AND TESTING

4.1 Field Exploration Program

The subsurface exploration program conducted for the project consisted of four (4) standard penetration test (SPT) borings drilled on August 23, 2022. The borings were drilled at the locations selected and marked in the field by WBK Engineering. The logs of the borings and details of the methods used appear in Appendix A. The logs contain information concerning soil layering, soil classification, geologic origins, and moisture condition. A density description or consistency is also noted for the natural soils, which is based on the standard penetration resistance (N-value).

The boring locations are shown on Figure 2: Boring Location Map included in Appendix A. Surface elevations at the boring locations were interpolated from the survey and boring location plans provided by 7 Generations Architecture & Engineering.

4.2 Laboratory Testing

The laboratory test program included natural moisture content, dry density, Atterberg Limits, percent passing #200 sieve, moisture-density relationship (Proctor), and California Bearing Ratio (CBR) tests. The test results appear in Appendix A on the individual boring logs adjacent to the samples upon which they were performed or on the data sheets following the logs. The moisture-density relationship (Standard Proctor) and CBR tests are included on separate sheets within Appendix A at the end of this report, and summarized as follows:

Boring Soil Classification Optimum Moisture

Content, % 1

Maximum Dry Density, pcf 1 CBR Value2

B-2/B-4 (Combined) 1’-5’ Bentonitic Fat Clay 21.8 99.1 1.2 1 Based on ASTM: D698 (standard proctor) 2Remolded to 95% of the maximum dry density

It should be noted the bulk soil sample represents a mixture of the soils encountered within the upper 5-foot interval of the boreholes. As such, the soil classification as presented on the Moisture-Density Relationship data sheet may differ from the classifications of the individual soil layers identified on the respective Subsurface Boring Log.

5.0 SITE CONDITIONS

5.1 Surface Observations

The project area is located on the west side of Conata Basin Road, approximately ½ mile south of the Badlands National Park Loop (SD-240), in Badlands National Park, South Dakota. The overall area along the existing access road and pavilion area is relatively flat, with natural prairie grass and scattered badland exposures covering the ground surface. In general, the overall drainage is to the south, with steep badlands above to the north of the project area. The access road is currently paved with approximately 1¾ to 2 inches of asphalt over approximately 4 to 5¼ inches of base course, as measured within our borings.

5.2 Subsurface Soils/Geology

Underlying the pavement section (Borings B-2 to B-4), the soils encountered consisted of stiff to hard bentonitic fat clay weathered claystone of the White River Group until the final depths explored of 6.5 feet below existing grade. Within Boring B-1, the soils encountered consisted of approximately 2.3 feet of stiff silt colluvium overlying the same hard bentonitic fat clay claystone of the White River Group until the final depth sampled of 16.5 feet below grade. The Subsurface Boring Logs included in Appendix A give a more detailed description of the soils encountered within the borings.

5.3 Groundwater

At the time of our field work, groundwater was not encountered within any of the soil borings.

The lack of groundwater noted at the boring locations should not be taken as an accurate representation of the actual groundwater levels. Groundwater levels can fluctuate due to varying seasonal and annual rainfall and snow melt amounts, as well as other factors including local irrigation practices and levels of water in drainage areas. A long period of time may be required for groundwater to stabilize in the soils present at the site; this period of time is generally not available during a typical subsurface exploration program.

6.0 RECOMMENDATIONS

6.1 Discussion

The following recommendations are based on the soil conditions observed in the soil borings at the time of our exploration. The bentonitic fat clay claystone soils at the site are known to be expansive, which is critical in the design of structures. To mitigate the expansive potential (heaving) of the bentonitic fat clay claystone soils present within the proposed pavilion structure, we recommend a minimum of 4 feet of imported granular engineered fill be placed below all floor slabs.

It is also our recommendation that a thickened-edge monolithic concrete slab be utilized for the pavilion foundation design, in place of the planned post and beam foundation design.

The near surface subgrade soils consisted of fat clay soils which are considered poor materials for pavement support and will control the pavement design analysis. However, changes in climatic conditions between the time of exploration and the time of construction may also affect soil conditions, particularly groundwater levels and the moisture content of the soils. Where applicable, we recommend that all work for the access road reconstruction be performed in accordance with the SDDOT Standard Specifications for Roads and Bridges, current edition.

At this time, we do not expect any significant grade changes once the existing asphalt pavement section is removed. Based on the laboratory test results, the clay soils along the alignment are near or above optimum moisture content. Therefore, it is anticipated that, once the existing pavement is removed, the subgrade may be soft and unstable upon initial exposure or at any time during construction if the clay subgrade is left open to the elements for an extended period of time. Due to these conditions, and if possible, we highly recommend that construction take place during warmer weather months (typically May through October) which will aid in the proper processing and moisture conditioning of the excavated site soils.

6.2 Site Preparation

We recommend all organic matter, topsoil, and any construction/manmade debris, if encountered, be removed from within the construction limits. As previously noted, the site bentonitic fat clays are highly expansive, as we do not recommend any structural elements be founded directly on these materials. Therefore, once site grading operations are completed and where required, excavations should continue to the desired construction elevations to allow for the placement of at least 4 feet of imported low frost suceptable granular engineered fill below the monolithic slab. The excavations should be laterally oversized at a 1H:1V ratio, from the outside edge of the thickened monolithic slab, to accommodate the 4 feet of granular engineered fill material.

The excavated soils, cleaned of all unsuitable/organic materials and aggregate greater than 3-inches in nominal size (if encountered), may be stockpiled on-site and reused as utility trench backfill, and overlot fill outside of the structure limits.

Where applicable, prior to placement of fill required to reach the desired site grades, we recommend that the subgrade soils be scarified to a depth of at least 8-inches, the moisture content adjusted to -1 to +3% of optimum, and the soils re-compacted to at least 95% of the maximum dry density, as determined by ASTM: D698 (Standard Proctor). Based upon the elevated moisture levels of the site soils measured in our borings, the contractor should anticipate drying of the subgrade soils to obtain compaction requirements. All exposed surfaces should be free of mounds and depressions which could prevent uniform compaction.

The required imported granular engineered fill within the building footprint should be pre-approved by the geotechnical engineer prior to use. The material should be a low frost susceptible pit run or crushed/screened material (crushed aggregate base course) with a maximum aggregate size of 2-inches, 40-85% passing the #4 sieve, and no more than 12% passing the #200 sieve with a Liquid Limit less than 25. Engineered fill should be placed in 8-inch thick maximum loose lifts; the moisture content conditioned to within ±3% of optimum moisture content and compacted to at least 95% of maximum dry density, as determined by ASTM: D698 (Standard Proctor).

It is our opinion the processed site soils are suitable for use as overlot fill outside the building footprint, where required. The moisture content of the fill soils should be adjusted to within -1 to +3% of optimum and the soils compacted to at least 95% of maximum dry density, as determined by ASTM: D698 (Standard Proctor). The compaction requirement can be reduced to 92% in landscaped/non-structural areas. Based on the results of the laboratory testing, processing and moisture conditioning of the site soils will be required prior to use.

Based upon our borings, we don’t anticipate groundwater will be encountered in the footing and utility excavations. However, please be aware that temporary dewatering of these excavations may be necessary if groundwater is encountered or surface drainage is allowed to accumulate in the excavations. Contractors working on the project should have equipment on-site that will lower and maintain the groundwater level at least two feet below the base of the excavations.

6.3 Monolithic Slab-On-Grade Foundation Recommendations

Based on our review, it is our recommendation that the pavilion structure be supported by a reinforced concrete monolithic slab-on-grade with thickened edges for wall support. As previously mentioned, the monolithic slab should bear on at least 4 feet of imported low frost susceptible granular engineered fill.

The monolithic slab may be designed for a maximum allowable bearing pressure of 2,000 pounds per square foot (psf). The design bearing pressure applies to dead load plus design live load conditions. It should be noted that because the monolithic slab is not allowed to ‘float’ independent of the foundation, differential movement and cracking between the slab and the thickened edge foundation may occur.

To address frost protection, we recommend the design comply with the requirements of ASCE 32-01 Frost Protected Shallow Foundations. We also recommend the insulation board be placed with a slight downward grade away from the foundation to prevent subsurface water from collecting on top of the board.

Slab construction control joints should be designed for load transfer from the slab to the thickened foundation section. The monolithic slab should be designed by a structural engineer to take this into account as well as the anticipated wall loads. If properly constructed, total and differential settlement should not exceed 1 inch and 1/2-inch, respectively.

To intercept potential water infiltration, an exterior foundation drain should be installed. A perforated PVC perimeter drain pipe, typically 4-inches in diameter, with a filter sock, should be placed at the outside base of the over-excavation perimeter. Additionally, the pipe should be embedded in free draining gravel. For proper drainage, the pipe should be graded at a minimum of 0.5 percent slope and connected to a collection pipe that discharges to a sump and pump system, storm sewer, or to a daylight point beyond the footprint of the structure.

6.4 Backfill Considerations

The on-site soils are at least moderately frost susceptible. Because of this, certain design considerations are needed to mitigate these frost effects. For details, we refer you to the attached sheet entitled “Freezing Weather Effects on Building Construction.” It is our opinion exterior backfill around the buildings should consist of the same imported granular non-expansive engineered fill. Over-lot grading material and utility trench backfill may consist of the on-site fat clay soils which should be placed as follows. We also recommend the fat clay site soils may be used as a 1-foot thick clay cap over the recommended granular engineered backfill. All recommendations are based on the Standard Proctor method (ASTM: D698).

1. All backfill should be free of deleterious/frozen material, and construction debris, and have a maximum aggregate size of 2-inches.

2. Cohesive (clay) backfill should be moisture conditioned to within -1 to +3% of optimum moisture content prior to being placed. Where utilized, relatively cohesionless (sand and gravel) backfill should be moisture conditioned to within ±3% prior to placement.

3. All backfill should be placed in loose lift thicknesses of 8-inches or less. If hand-operated compaction equipment is used, the loose lift thickness should be reduced to 4-inches or less.

4. Each lift should be compacted to at least 95% of maximum proctor density. We recommend the final lift of backfill be compacted to at least 98% of the maximum dry density.

5. Compaction density tests should be performed on alternating lifts to ensure the minimum density is maintained.

6. Utility lines entering or exiting the structures should be leak tested prior to the placement of the slab.

Should additional fill be required, the proposed import backfill should be submitted to the geotechnical engineer for approval prior to use.

6.5 Asphalt Pavement

6.5.1 Subgrade Preparation

Based on our observations during our field work, the existing roadway alignment has experienced distress related issues, which in our opinion, is likely due to the presence of the fat clay subgrade soils. Experience has shown that fat clays soils are moisture sensitive, and extra care must be taken during reworking and compaction of these soils to obtain a uniform moisture content throughout the fill. To obtain the recommended compaction requirements, experience has shown that the in-place moisture content should be within the specified range. Moisture contents outside this range will result in greater difficulty in obtaining specified compaction.

Additionally, the use of high modulus geotextile, such as Mirafi RS380i, or approved equivalent, is recommended at the subgrade interface for separation and reinforcement purposes.

Once the existing pavement section has been removed, and prior to placement of the geotextile, the exposed subgrade soils should be scarified to a depth of 8-inches, the moisture content of the scarified soils adjusted to -1 to +3 percent of the optimum moisture content, and the material compacted to at least 95% of maximum standard Proctor dry density (ASTM D698). All prepared subgrades should be proof rolled with a loaded dump truck or front end loader to verify a firm and unyielding subgrade has been obtained prior to the placement of the new pavement section.

To obtain a firm and unyielding subgrade, on which to construct the new pavement section, scarification and drying of the subgrade soils should be anticipated. This scarification process may need to be repeated over several days in order to allow the soils to dry back to an acceptable moisture content. The earthwork contractor should be made aware of the soil conditions at the site and account for the anticipated subgrade preparation work.

Any areas that "pump" during proof rolling should be evaluated by the geotechnical engineer to determine whether remediation may be required. Once the subgrade has been proof rolled and approved, the geotextile material and associated pavement section may be placed.

6.5.1 Pavement Design Considerations

The following pavement sections were designed based on the procedures outlined in the 1993 AASHTO Empirical Equation for Flexible Pavements and Rigid Pavements. It is anticipated that the access road will be utilized by low to moderate traffic volumes consisting primarily of passenger cars/trucks, as well as any park maintenance vehicles.

Therefore, based on our analysis and because anticipated traffic numbers have not been provided to us, an equivalent 20-year design 18-kip single axle load (ESAL) of 50,000 was assumed for the access road section.

It is anticipated that pavement subgrade soils will primarily consist of fat clay soils which are considered poor materials for pavement support. Based on the laboratory test results, a CBR value of 1.2 was used in the pavement design.

Other parameters used in the design of the recommended pavement sections include:

Design Criteria Design Parameter

Modulus of Subgrade Reaction (k) 100 Overall Design Standard Deviation 0.45

Soil Resilient Modulus CBR x 1500 Initial Serviceability 4.2

Terminal Serviceability 2.0 Reliability, % 80

Drainage Coefficient 0.75 (no edge drains)

6.5.2 Pavement Section Recommendations

Based on the above stated information and our analysis, we recommend the following pavement sections be used for this project:

Street Section Asphalt, inches Aggregate Base Course, inches

Geotextile Reinforcement

Total, inches

Access Road 4 8 Mirafi RS580i 12

We recommend the asphalt be obtained from an approved mix design conforming to the South Dakota Department of Transportation (SDDOT) Class E Specifications as defined in Sections 320 and 321 of the “Standard Specifications for Road and Bridges”, current edition.

Aggregate used in the asphalt should meet SDDOT specifications under Section 880 “Aggregate for Asphalt Concrete” for quality and gradation. Mix designs should be submitted prior to construction to verify their adequacy.

6.5.3 Aggregate Base Course

Aggregate base course gravel should be moisture conditioned to within ±3% of optimum and compacted to a minimum of 95% of maximum density as determined by the standard Proctor method (ASTM: D698) and should meet the requirements as outlined in Section 882 “Aggregates for Granular Bases and Surfacing” of the SDDOT specifications.

6.6 Pavement Maintenance

The pavement sections provided in this report represent minimum recommended thicknesses and, as such, periodic maintenance should be anticipated. Therefore, preventive maintenance should be planned and provided for through an on-going pavement management program.

Preventive maintenance activities are intended to slow the rate of pavement deterioration.

Pavement maintenance consists of both localized maintenance (crack and joint sealing and patching) and global maintenance (surface sealing).

Preventive maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements. Prior to implementing any maintenance program, additional engineering input is recommended to determine the type and extent of preventive maintenance appropriate. Even with periodic maintenance, some movements and related cracking may still occur and repairs may be required.

7.0 CONSTRUCTION CONSIDERATIONS

7.1 Potential Difficulties

7.1.1 Soft Subgrade Soils

Depending on the time of year in which construction takes place, unstable subgrade soils could be encountered during grading operations. If encountered, additional conditioning of the soils may be required to obtain moisture contents which allow for firm and unyielding subgrade and/or compaction.

Localized areas of soft wet subgrades can be remedied with additional excavation to expose firmer soils, placement of coarse rock to provide a solid base on which to place additional fill and/or the use of geotextiles between the soft soils and the overlying fill and/or pavement sections. The appropriate means of subgrade stabilization should be evaluated by the geotechnical engineer at the time of construction.

7.1.2 Runoff Water in Excavation

Water can be expected to collect in the excavation bottom during times of inclement weather or snow melt. To allow observation of the excavation bottom, to reduce the potential for soil disturbance, and to facilitate filling operations, we recommend water be removed from within the excavation during construction. Based on the soils encountered, we anticipate the groundwater can be handled with conventional sump pumping.

7.2 Excavation Backsloping

If excavation faces are not retained, the excavations should maintain maximum allowable slopes in accordance with OSHA Regulations (Standards 29 CFR), Part 1926, Subpart P, “Excavations” (can be found on www.osha.gov). Even with the required OSHA sloping, water seepage or surface runoff can potentially induce sideslope erosion or sloughing which could require slope maintenance.

7.3 Observation and Testing

The recommendations in this report are based on the subsurface conditions found at our test boring locations. Since the soil conditions can be expected to vary away from the soil boring locations, we recommend on-site observation by a geotechnical engineer/technician during construction to evaluate these potential changes. Soil density testing should also be performed on new fill placed in order to document that project specifications for compaction have been satisfied.

8.0 LIMITATIONS

Within the limitations of scope, budget, and schedule, we have endeavored to provide our services according to generally accepted geotechnical engineering practices at this time and location. Other than this, no warranty, expressed or implied, is intended. Important information regarding risk management and proper use of this report is given in Appendix B entitled “Geotechnical Report Limitations and Guidelines for Use.”

Appendix A

Geotechnical Field Exploration and Testing Boring Log Notes

Unified Soil Classification System Figure 1: Site Location Map

Figure 2: Boring Location Map Subsurface Boring Logs

Moisture-Density Relationship (Proctor) Report California Bearing Ratio (CBR)Test Report

Appendix A - Page 1 of 2 AMERICAN ENGINEERING TESTING, INC.

A.1 FIELD EXPLORATION

The subsurface conditions at the site were explored by drilling and sampling standard penetration test (SPT) borings. The locations of the borings appear on Figure 2, preceding the Subsurface Boring Logs in this appendix.

A.2 SAMPLING METHODS

A.2.1 Split-Spoon Samples (SS) - Calibrated to N60 Values Standard penetration (split-spoon) samples were collected in general accordance with ASTM: D1586 with one primary modification. The ASTM test method consists of driving a 2-inch O.D. split-barrel sampler into the in-situ soil with a 140-pound hammer dropped from a height of 30 inches.

The sampler is driven a total of 18 inches into the soil. After an initial set of 6 inches, the number of hammer blows to drive the sampler the final 12 inches is known as the standard penetration resistance or N-value. Our method uses a modified hammer weight, which is determined by measuring the system energy using a Pile Driving Analyzer (PDA) and an instrumented rod.

In the past, standard penetration N-value tests were performed using a rope and cathead for the lift and drop system. The energy transferred to the split-spoon sampler was typically limited to about 60% of its potential energy due to the friction inherent in this system. This converted energy then provides what is known as an N60 blow count.

The most recent drill rigs incorporate an automatic hammer lift and drop system, which has higher energy efficiency and subsequently results in lower N-values than the traditional N60 values. By using the PDA energy measurement equipment, we are able to determine actual energy generated by the drop hammer. With the various hammer systems available, we have found highly variable energies ranging from 55% to over 100%. Therefore, the intent of AET’s hammer calibrations is to vary the hammer weight such that hammer energies lie within about 60% to 65% of the theoretical energy of a 140-pound weight falling 30 inches. The current ASTM procedure acknowledges the wide variation in N-values, stating that N-values of 100% or more have been observed. Although we have not yet determined the statistical measurement uncertainty of our calibrated method to date, we can state that the accuracy deviation of the N-values using this method is significantly better than the standard ASTM Method.

A.2.2 Disturbed Samples (DS)/Spin-up Samples (SU) Sample types described as “DS” or “SU” on the boring logs are disturbed samples, which are taken from the flights of the auger. Because the auger disturbs the samples, possible soil layering and contact depths should be considered approximate.

A.2.3 Sampling Limitations Unless actually observed in a sample, contacts between soil layers are estimated based on the spacing of samples and the action of drilling tools.

Cobbles, boulders, and other large objects generally cannot be recovered from test borings, and they may be present in the ground even if they are not noted on the boring logs.

Determining the thickness of “topsoil” layers is usually limited, due to variations in topsoil definition, sample recovery, and other factors. Visual-manual description often relies on color for determination and transitioning changes can account for significant variation in thickness judgment.

Accordingly, the topsoil thickness presented on the logs should not be the sole basis for calculating topsoil stripping depths and volumes. If more accurate information is needed relating to thickness and topsoil quality definition, alternate methods of sample retrieval and testing should be employed.

A.3 CLASSIFICATION METHODS

Soil descriptions shown on the boring logs are based on the Unified Soil Classification (USC) system. The USC system is described in ASTM:

D2487 and D2488. Where laboratory classification tests (sieve analysis or Atterberg Limits) have been performed, accurate classifications per ASTM: D2487 are possible. Otherwise, soil descriptions shown on the boring logs are visual-manual judgments. Charts are attached which provide information on the USC system, the descriptive terminology, and the symbols used on the boring logs.

The boring logs include descriptions of apparent geology. The geologic depositional origin of each soil layer is interpreted primarily by observation of the soil samples, which can be limited. Observations of the surrounding topography, vegetation, and development can sometimes aid this judgment.

Appendix A - Page 2 of 2 AMERICAN ENGINEERING TESTING, INC.

A.4 WATER LEVEL MEASUREMENTS

The ground water level measurements are shown at the bottom of the boring logs. The following information appears under “Water Level Measurements” on the logs:

Date and Time of measurement Sampled Depth: lowest depth of soil sampling at the time of measurement Casing Depth: depth to bottom of casing or hollow-stem auger at time of measurement Cave-in Depth: depth at which measuring tape stops in the borehole Water Level: depth in the borehole where free water is encountered Drilling Fluid Level: same as Water Level, except that the liquid in the borehole is drilling fluid

The true location of the water table at the boring locations may be different than the water levels measured in the boreholes. This is possible because there are several factors that can affect the water level measurements in the borehole. Some of these factors include: permeability of each soil layer in profile, presence of perched water, amount of time between water level readings, presence of drilling fluid, weather conditions, and use of borehole casing.

A.5 LABORATORY TEST METHODS

A.5.1 Water Content Tests Conducted per AET Procedure 01-LAB-010, which is performed in general accordance with ASTM: D2216 and AASHTO: T265.

A.5.2 Atterberg Limits Tests Conducted per AET Procedure 01-LAB-030, which is performed in general accordance with ASTM: D4318 and AASHTO: T89, T90.

A.5.3 Sieve Analysis of Soils (thru #200 Sieve) Conducted per AET Procedure 01-LAB-040, which is performed in general conformance with ASTM: D6913, Method A.

A.5.4 Particle Size Analysis of Soils (with hydrometer) Conducted per AET Procedure 01-LAB-050, which is performed in general accordance with ASTM: D422 and AASHTO: T88.

A.5.5 Unconfined Compressive Strength of Cohesive Soil Conducted per AET Procedure 01-LAB-080, which is performed in general accordance with ASTM: D2166 and AASHTO: T208.

A.5.6 Laboratory Soil Resistivity using the Wenner Four-Electrode Method Conducted per AET Procedure 01-LAB-090, which is performed using Soil Box apparatus in the laboratory in general accordance with ASTM: G57

A.6 TEST STANDARD LIMITATIONS

Field and laboratory testing is done in general conformance with the described procedures. Compliance with any other standards referenced within the specified standard is neither inferred nor implied.

A.7 SAMPLE STORAGE

Unless notified to do otherwise, we routinely retain representative samples of the soils recovered from the borings for a period of 30 days.

M

M

M

M

M

M

M

50/.4

50/.4

50/.4

97/.8

50/.4

92/.7

COLLUVIUM

WHITE

RIVER

GROUP 24

SILT, tan, stiff (ML)

CLAYSTONE, Bentonitic Fat Clay, light gray-brown, hard (CH)

Bottom of Boring

SS

SS

MC

SS

SS

SS

SS

SS

BORING

COMPLETED:

ES SC

2616.0

16.2

DEPTH: WATER LEVEL MEASUREMENTS

None

WATER

LEVEL

Rig:

13:28

Surface Elevation

LG:

TIME

8/23/22

SAMPLED

DEPTH15.0

DATE

NA

4" FA

RC-106

NA

DRILLING

FLUID LEVEL

DR:

16.2

DRILLING METHOD NOTE: REFER TO

THE ATTACHED

SHEETS FOR AN

EXPLANATION OF

TERMINOLOGY ON

THIS LOG

CASING

DEPTH

8/23/22

CAVE-IN

DEPTH

WC

N

DENMATERIAL DESCRIPTION

REC

IN.

B-1 (p. 1 of 1)

MCGEOLOGY

AET No:

Project:

DEPTH

IN

FEET

SAMPLE

TYPE

03/2011 01-DHR-060

LL

FIELD & LABORATORY TESTS

Proposed Conata Picnic Area Reconstruction; Badlands National Park, SD

Log of Boring No.

%-#200PL

P-0015784

SUBSURFACE BORING LOG

A

E T

_C O

R P

-0

.G P

J A

E T

C

P T

W

E

LL

.G D

T

9/ 2/

M

PAVEMENT

FILL

WHITE

RIVER

GROUP

ASPHALT, 2 inches BASE COURSE, 4 inches WEATHERED CLAYSTONE, Bentonitic Fat Clay, light grayish brown, stiff to hard (CH)

Bottom of Boring

SS

SS

SS

BORING

COMPLETED:

ES SC

2615.0

6.5

DEPTH: WATER LEVEL MEASUREMENTS

None

WATER

LEVEL

Rig:

14:06

Surface Elevation

LG:

TIME

8/23/22

SAMPLED

DEPTH15.0

DATE

NA

4" FA

RC-106

NA

DRILLING

FLUID LEVEL

DR:

6.5

DRILLING METHOD NOTE: REFER TO

THE ATTACHED

SHEETS FOR AN

EXPLANATION OF

TERMINOLOGY ON

THIS LOG

CASING

DEPTH

8/23/22

CAVE-IN

DEPTH

WC

N

DENMATERIAL DESCRIPTION

REC

IN.

B-2 (p. 1 of 1)

MCGEOLOGY

AET No:

Project:

DEPTH

IN

FEET

SAMPLE

TYPE

03/2011 01-DHR-060

LL

FIELD & LABORATORY TESTS

Proposed Conata Picnic Area Reconstruction; Badlands National Park, SD

Log of Boring No.

%-#200PL

P-0015784

SUBSURFACE BORING LOG

A

E T

_C O

.G P

J A

E T

C

P T

W

E

LL

.G

M

PAVEMENT

FILL

WHITE

RIVER

GROUP

ASPHALT, 1 3/4 inches BASE COURSE, 4 1/2 inches WEATHERED CLAYSTONE, Bentonitic Fat Clay, light grayish brown, stiff to hard (CH)

Bottom of Boring

10720

SS

SS

SS

BORING

COMPLETED:

ES SC

2614.0

6.5

DEPTH: WATER LEVEL MEASUREMENTS

None

WATER

LEVEL

Rig:

13:44

Surface Elevation

LG:

TIME

8/23/22

SAMPLED

DEPTH15.0

DATE

NA

4" FA

RC-106

NA

DRILLING

FLUID LEVEL

DR:

6.5

DRILLING METHOD NOTE: REFER TO

THE ATTACHED

SHEETS FOR AN

EXPLANATION OF

TERMINOLOGY ON

THIS LOG

CASING

DEPTH

8/23/22

CAVE-IN

DEPTH

WC

N

DENMATERIAL DESCRIPTION

REC

IN.

B-3 (p. 1 of 1)

MCGEOLOGY

AET No:

Project:

DEPTH

IN

FEET

SAMPLE

TYPE

03/2011 01-DHR-060

LL

FIELD & LABORATORY TESTS

Proposed Conata Picnic Area Reconstruction; Badlands National Park, SD

Log of Boring No.

%-#200PL

P-0015784

SUBSURFACE BORING LOG

A

E T

_C O

.G P

J A

E T

C

P T

W

E

LL

.G

M

PAVEMENT

FILL

WHITE

RIVER

GROUP

ASPHALT, 2 inches BASE COURSE, 5 1/4 inches WEATHERED CLAYSTONE, Bentonitic Fat Clay, light grayish brown, firm to hard (CH)

Bottom of Boring

99 8225

SS

SS

SS

BORING

COMPLETED:

ES SC

2618.0

6.5

DEPTH: WATER LEVEL MEASUREMENTS

None

WATER

LEVEL

Rig:

14:29

Surface Elevation

LG:

TIME

8/23/22

SAMPLED

DEPTH15.0

DATE

NA

4" FA

RC-106

NA

DRILLING

FLUID LEVEL

DR:

6.5

DRILLING METHOD NOTE: REFER TO

THE ATTACHED

SHEETS FOR AN

EXPLANATION OF

TERMINOLOGY ON

THIS LOG

CASING

DEPTH

8/23/22

CAVE-IN

DEPTH

WC

N

DENMATERIAL DESCRIPTION

REC

IN.

B-4 (p. 1 of 1)

MCGEOLOGY

AET No:

Project:

DEPTH

IN

FEET

SAMPLE

TYPE

03/2011 01-DHR-060

LL

FIELD & LABORATORY TESTS

Proposed Conata Picnic Area Reconstruction; Badlands National Park, SD

Log of Boring No.

%-#200PL

P-0015784

SUBSURFACE BORING LOG

A

E T

_C O

.G P

J A

E T

C

P T

W

E

LL

.G

Sample Details Sample ID: AET-078951-S1 Field ID: Bulk B-2 & 4 1-5' Date Sampled: 8/23/2022 Material: Fat Clay, gray-brown (CH) Location: Boring B-2 & 4 (Combined)

Test Results

ASTM D 698

Maximum Dry Unit Weight (lbf/ft³): 99.1 Optimum Water Content (%): 21.8 Method: A Preparation Method: Moist Specific Gravity (Fines): 2.65 Specific Gravity Method: Assumed Retained Sieve No 4 (4.75mm) (%): 1 Passing Sieve No 4 (4.75mm) (%): 99 Tested By: (unknown) Date Tested:

Dry Unit Weight - Water Content Relationship

American Engineering Testing, Inc.

Rapid City 1745 Samco Road Rapid City, SD 57702

(605) 388-0029 www.teamAET.com

Report No: PTR:AET-078951-S1

Project: Proposed Conata Picnic Area

Client:

8/26/2022Date of Issue:

CC:7 Generations Architecture and Engineering

Badlands National Park SD Job No: P-0015784

Proctor Report

Page 1 of 1Form No: 110031, Report No: PTR:AET-078951-S1 © 2000-2022 QESTLab by SpectraQEST.com

Comments

Molded Soaked CBR, (%) Pen. Swell

Dens. % Max. % Moisture Dens. % Max. % Moisture 0.1 in 0.2 in Surcharge %

94.1 95.0 21.8 90.6 91.4 27.3 1.2 0.9 10lb 4.0

USCS Max. Dens. Opt. Mois. LL PI

CH 99.1 21.8

Project No:P-0015784 Bulk B-2 & 4 1-5'

Project: Proposed Conata Picnic Area Reconstruction CBR: ASTM: D1883 Badlands National Park, South Dakota

Date: 9/7/2022 Proctor: ASTM: D698

BEARING RATIO TEST REPORT

Test Descr. / Remarks

MATERIAL DESCRIPTION

Bentonitic Fat Clay

0.000 0.100 0.200 0.300 0.400 0.500 0.600

P en et ra ti o n R es is ta n ce , p si

Penetration, in

0 24 48 72 96

S w el l, Elapsed Time, hrs

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

85.0 90.0 95.0 100.0 105.0 110.0

C B

R

Molded Density, pcf

CBR @ 94.1 pcf = 1.2% for 0.1 in penetration

Appendix B

Appendix B – Page 1 of 3 AMERICAN ENGINEERING TESTING, INC.

B.1 REFERENCE

This appendix provides information to help you manage your risks relating to subsurface problems which are caused by construction delays, cost overruns, claims, and disputes. This information was developed and provided by GBA1, of which, we are a member firm.

B.2 RISK MANAGEMENT INFORMATION

B.2.1 Understand the Geotechnical Engineering Services Provided for this Report Geotechnical engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities.

The culmination of these geotechnical engineering services is typically a geotechnical engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project. These reports may be titled investigations, explorations, studies, assessments, or evaluations. Regardless of the title used, the geotechnical engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions.

B.2.2 Geotechnical Engineering Services are Performed for Specific Purposes, Persons, and Projects, and At Specific Times Geotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical engineering study is unique, each geotechnical engineering report is unique, prepared solely for the client.

Likewise, geotechnical engineering services are performed for a specific project and purpose. For example, it is unlikely that a geotechnical engineering study for a refrigerated warehouse will be the same as one prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project.

Do not rely on this report if your geotechnical engineer prepared it:

• for a different client;

• for a different project or purpose;

• for a different site (that may or may not include all or a portion of the original site); or

• before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations.

Note, too, the reliability of a geotechnical-engineering report can be affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it. A minor amount of additional testing or analysis after the passage of time – if any is required at all – could prevent major problems.

1 Geoprofessional Business Association, 1300 Piccard Drive, LL14, Rockville, MD 20850

Telephone: 301/565-2733: www.geoprofessional.org, 2019

B.2.3 Read the Full Report Costly problems have occurred because those relying on a geotechnical-engineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full.

Appendix B – Page 2 of 3 AMERICAN ENGINEERING TESTING, INC.

B.2.4 You Need to Inform Your Geotechnical Engineer About Change Your geotechnical engineer considered unique, project-specific factors when developing the scope of study behind this report and developing the confirmation-dependent recommendations the report conveys. Typical changes that could erode the reliability of this report include those that affect:

• the site’s size or shape;

• the elevation, configuration, location, orientation, function or weight of the proposed structure and the desired performance criteria;

• the composition of the design team; or

• project ownership.

As a general rule, always inform your geotechnical engineer of project or site changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered.

B.2.5 Most of the “Findings” Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site’s subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing is performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team through project completion to obtain informed guidance quickly, whenever needed.

B.2.6 This Report’s Recommendations Are Confirmation-Dependent The recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions exposed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation.

B.2.7 This Report Could Be Misinterpreted Other design professionals’ misinterpretation of geotechnical engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to:

• confer with other design-team members;

• help develop specifications;

• review pertinent elements of other design professionals’ plans and specifications; and

• be available whenever geotechnical engineering guidance is needed.

You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction-phase observations.

B.2.8 Give Constructors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for information purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect.

Appendix B – Page 3 of 3 AMERICAN ENGINEERING TESTING, INC.

B.2.9 Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. This happens in part because soil and rock on project sites are typically heterogeneous and not manufactured materials with well-defined engineering properties like steel and concrete. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly.

B.2.10 Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical engineering study. For that reason, a geotechnical engineering report does not usually provide environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures.