Report_Geotech.pdf

REPORT OF GEOTECHNICAL EXPLORATION

Disaster Roadway Reconstruction and Drainage Repairs

WI ERFO FS 2016-1(2)

Chequamegon-Nicolet National Forest AET Project No. 12-02938

Date:

January 22, 2018

Prepared for:

Stantec 2335 Highway 36 West St. Paul, Minnesota 55113

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

4203 Schofield Avenue, Suite 1 ▪ Schofield, Wisconsin 54476 ▪ 715-359-3534 ▪ www.amengtest.com

AN AFFIRMATIVE ACTION AND EQUAL OPPORTUNITY EMPLOYER

Page i

A

AMERICAN

ENGINEERING

TESTING, INC.

Mr. Tom Fidler, Senior Engineer Stantec 2335 Highway 36 West St. Paul, Minnesota 55113

RE: Report of Geotechnical Exploration

WI ERFO FS 2016-1(2)

Chequamegon-Nicolet National Forest AET Project No. 12-02938

Dear Mr. Fidler:

We are pleased to present the results of our subsurface exploration program for your projects in the Chequamegon-Nicolet National Forest. These services were performed according to our proposal to you dated October 9, 2017.

We are submitting an electronic (PDF) version of this geotechnical report to you. Unless you request otherwise, we will not submit any hard copies of the report.

We appreciate the opportunity to work with you on this phase of the project. Please contact us if you have questions about this report or require further assistance.

Sincerely, American Engineering Testing, Inc.

Benjamin B. Mattson, P.E. Gregory C. Owens, P.G.

Senior Geotechnical Engineer

Report of Geotechnical Exploration

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN January 22, 2018 ENGINEERING AET Project No. 12-02938 TESTING, INC.

Page iii

TABLE OF CONTENTS

Transmittal Letter............................................................................................................................. i Signature Page ................................................................................................................................ ii TABLE OF CONTENTS ............................................................................................................... iii

1.0 INTRODUCTION

2.0 SCOPE OF SERVICE

3.0 PROJECT INFORMATION

4.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING

5.0 SUBSURFACE CONDITIONS

5.1 Location 2: Boring S6

5.2 Location 4: Boring S10

5.3 Location 4: Boring S-11

5.4 Location 3a: Boring W14W

5.5 Location 3a: Boring W14E

5.6 Additional Groundwater Comments

6.0 CULVERT RECOMMENDATIONS (LOCATIONS 2 AND 4)

6.1 Approach Discussion

6.2 Location 2: Site S6

6.3 Location 4: Site S10

6.4 Location 4: Site S11

7.0 ROADWAY RECONSTRUCTION (LOCATION 3a)

7.1 Fill Placement and Compaction

7.2 Pavement Design Parameters

8.0 CONSTRUCTION CONSIDERATIONS

8.1 Groundwater

8.2 Disturbance of Soils

8.3 Excavation Backsloping

8.4 Observation and Testing

9.0 LIMITATIONS

APPENDIX A Geotechnical Field Exploration and Testing Boring Log Notes Unified Soil Classification System Figure 1 – Boring Locations (1 of 3) Figure 2 – Boring Locations (2 of 3) Figure 3 – Boring Locations (3 of 3) Subsurface Boring Logs Gradation Curves Photo Log

APPENDIX B Geotechnical Report Limitations and Guidelines for Use

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN

1.0 INTRODUCTION

Stantec is providing planning and design services for several projects in the Chequamegon-Nicolet National Forest. To assist with planning and design, Stantec authorized American Engineering Testing, Inc. (AET) to conduct a subsurface exploration program at the site 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 SERVICE

AET's services were performed according to our proposal to Stantec dated October 9, 2017. The authorized scope consists of the following:

• Five standard penetration test borings to depths of 30 feet each or to refusal, whichever occurs first.

• Visual/manual classification and limited laboratory testing of the recovered soil samples.

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

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

3.0 PROJECT INFORMATION

The projects include road and drainage repairs necessitated by the 1000-year rain event that occurred in July 2016. Projects that are a subject of this report are described below.

• Location 2 (Site S6): Large culvert replacement along Forest Service Road 198. No survey details are available for this location. However, design drawings for the pre-rain-event culvert indicate a corrugated metal pipe (CMP) arch culvert having dimensions of 87” x 63” x 60’. Design elevations (datum unknown) were 100.45 feet at the road centerline, and invert elevations of 90.50 and 89.75 feet. Following the rain event, a temporary CMP arch culvert was installed, having a span of 7.3 feet and a rise of 5.3 feet; the invert elevation is not known. Dimensions of the new culvert, which will replace the temporary culvert, are not yet decided. For the purpose of this report, we assume the type, dimensions, and elevations of the new culvert will be similar to the temporary culvert.

• Location 3a (Site W14): Reconstruction of a washed-out 0.60-mile section of Forest Service Road 198. Based on our field crew’s observations, the washout removed up to about 8 feet of soil; the reconstruction will require the replacing of this material, in addition to constructing the new surface.

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN

• Location 4 (Sites S10 and S11): Replace two large culverts along Forest Service Road 205.

The post-rain-event temporary S10 culvert is a 29” x 42” CMP arch culvert; the surveyed road centerline is 1398.8 feet and the invert elevations are 1390.48 and 1390.81 feet. The S11 culvert is a 24-inch diameter CMP culvert; the surveyed road centerline 1400.6 feet and the invert elevations are 1393.83 and 1394.16 feet. Dimensions of the new culverts, which will replace the temporary culverts, are not yet decided. For the purpose of this report, we assume both of the new culverts will also be CMP with invert elevations similar to existing.

The above-stated information represents our understanding of the proposed construction and is an integral part of our engineering review. It is important we be contacted if there are changes from that described so we can evaluate if modifications to our recommendations are appropriate.

4.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING

Our subsurface exploration program for this project consisted of drilling five borings with standard penetration testing (SPT) and sampling on December 20 and 21, 2017. Stantec specified the number, depths, and approximate locations of the borings, which are shown on Figures 1, 2, and 3 in Appendix A. Table 1 below provides location details of the borings.

Table 1: Boring Details

Site/Boring Road Latitude Longitude

S6 FS 198 46.301993 -90.915782

S10 FS 205 46.107094 -91.166114

S11 FS 205 46.116988 -91.148717

W14W FS 198 46.296088 -91.006948

W14E FS 198 46.290508 -90.987848

Prior to drilling, we contacted Wisconsin Diggers Hotline to locate public underground utilities at the site. We drilled the borings using 3¼-inch inside-diameter hollow-stem augers and mud rotary techniques. Refer to Appendix A for details on the drilling and sampling methods, the classification methods, and the water level measurement details. Several representative photographs of each boring are also included in Appendix A.

The boring logs are found in Appendix A and contain information concerning soil layering, geologic description, moisture condition, and USCS classifications. Relative density or

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN consistency is also noted for the natural soils, which are based on the standard penetration resistance (N-value).

We performed six gradation (sieve) tests on the recovered soil samples; the test results are included in Appendix A.

5.0 SUBSURFACE CONDITIONS

5.1 Location 2: Boring S6

Boring S6, which was drilled at Location 2, encountered about 4.5 feet of fill overlying coarse alluvium and till. These materials were primarily sand with varying amounts of sand and gravel.

We measured groundwater at a depth of 8.2 feet, which appears to approximately match the creek level.

5.2 Location 4: Boring S10

Boring S10, which was drilled at the southwest culvert at Location 4, encountered about 7 feet of granular fill, overlying wood from about 7 to 9.5 feet, overlying a 1-foot thick layer of silty sand and then swamp deposits from about 10.5 to 13.5 feet. Below these materials, we encountered coarse alluvium and till, each of which consisted of sand with varying silt and gravel contents. We measured groundwater at a depth of 6.6 feet, which appears to approximately match the creek level.

5.3 Location 4: Boring S-11

Boring S11, which was drilled at the northeast culvert at Location 4, encountered about 4.5 feet of granular fill overlying coarse alluvium and till, which each consisted of silty sand with a little gravel. We measured groundwater at a depth of 23.7 feet, but we noted saturated soils at about 7 feet; the shallower depth appears to approximately match the creek level.

5.4 Location 3a: Boring W14W

Boring W14W, which was drilled at the west end of the washout area, encountered coarse alluvium and till, each consisting of sand with varying silt and gravel contents. The bottom layer of till was clayey gravel with sand. We encountered auger refusal at a depth of 12.5 feet, but we do not know if the refusal was caused by a boulder or bedrock. We measured groundwater at a depth of 2.4 feet, but this level appeared to be perched and not the static water table.

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN

5.5 Location 3a: Boring W14E

Boring W14E, which was drilled near the east end of the washout area, encountered only coarse alluvium, consisting mostly of silty sand with varying gravel content. The bottom layer was gravel (rock chips). We encountered auger refusal at a depth of 12.4 feet, but we do not know if the refusal was caused by a boulder or bedrock. We measured groundwater at a depth of 8.8 feet.

5.6 Additional Groundwater Comments

The installation of piezometers for obtaining additional groundwater level measurements was beyond our scope of service. Groundwater levels will fluctuate due to varying seasonal and annual rainfall and snow melt amounts and other factors.

6.0 CULVERT RECOMMENDATIONS (LOCATIONS 2 AND 4)

6.1 Approach Discussion

Section 6.4.5.1 of the Federal Lands Highway (FLH) Project Development and Design Manual (PDDM) states:

Project specific geotechnical recommendations on culverts and pipes are not usually provided. FLH Standard Drawings address considerations such as bedding and minimum cover based on pipe diameter and material type.

FLH Standard Drawing 602-1 describes metal pipe culvert (round and arch) sizes, which covers the range of culvert sizes likely for these projects. FLH Standard Drawing 602-3 describes excavation and bedding requirements. For the purpose of our geotechnical report, we will present our geotechnical discussion in reference to these drawings. If any of the new culverts will include a concrete foundation such that geotechnical analyses are required (e.g. LRFD for a box culvert), contact us for additional recommendations.

6.2 Location 2: Site S6

Based on the soils we encountered in boring S6, we anticipate dense to very dense granular soils will be encountered at the new culvert invert depth. Provided the contractor uses suitable methods, it is likely a competent subgrade will be present at culvert bottom elevation, and that overexcavation will only be needed to provide the required bedding thickness. The existing soils at this site will probably not be suitable for use as bedding material, due to the amount of gravel.

The FLH manual Standard Specifications for Construction of Roads and Bridges on Federal

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN

Highway Projects (FP-14) includes item 704.02, bedding material, which dictates: (1) a maximum particle size of ½ inch or half the corrugation depth, whichever is smaller, and (2) a maximum of 10 percent by weight passing the No. 200 sieve. The contractor will probably have to perform construction dewatering to reduce the risk of subgrade disturbance.

6.3 Location 4: Site S10

Based on the soils we encountered in boring S10, we anticipate that unstable materials (wood, swamp deposits) will be encountered near and below bottom of culvert elevation. Based on our boring, the project team should assume that subcutting will be needed to a depth of about 13.5 feet (which is 5.5 feet below the existing culvert elevation). However, it is possible these materials were removed during the original (or temporary post-event) culvert installations, and that our boring was performed outside of any zone of previous correction. Per FLH Standard Drawing 602- 3, the subcut zone should be backfilled with properly compacted granular foundation fill material.

Due to the likelihood of wet subgrade conditions, we recommend the backfill meet the requirements of Standard Specification 704.01 (Foundation Fill) or 704.07 (Select Borrow), with the final layer of fill below the culvert consisting of the bedding layer. Each lift should be a maximum of 6 inches thick; we recommend each lift be compacted to at least 95% of the maximum modified Proctor dry density for that material. The contractor will probably have to perform construction dewatering to reduce the risk of subgrade disturbance.

6.4 Location 4: Site S11

Based on the soils we encountered in boring S11, we anticipate loose to medium dense granular soils will be encountered at the new culvert invert depth. Provided the contractor uses suitable methods, it is likely a competent subgrade will be present at culvert bottom elevation, and that overexcavation will only be needed to provide the required bedding thickness. The existing soils at this site will probably not be suitable for use as bedding material, due to the relatively high fines content. The contractor will probably have to perform construction dewatering to reduce the risk of subgrade disturbance.

7.0 ROADWAY RECONSTRUCTION (LOCATION 3A)

7.1 Fill Placement and Compaction

The soils we encountered in borings W14W and W14E are competent and suitable for supporting new fill to re-establish roadway grade. Soil conditions will vary along the roadway reconstruction

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN alignment and it is possible there are areas that are less competent. All debris and wet or soft soil must be removed from areas that will receive new fill.

New fill placed to establish roadway grade should be non-organic, granular soil. For ease of placement and compaction, we recommend the fill have a maximum aggregate size of about 3 inches and have less than 20% by weight passing the No. 200 sieve; however, other soils could be used, but it would probably be more difficult to attain the desired or required compaction level.

Fill placed to attain subgrade elevation for the roadway should be compacted in thin lifts, such that the entire lift achieves a minimum compaction level of 95% of the maximum modified Proctor dry density. We anticipate a lift thickness on the order of 4 to 8 inches may be appropriate, although this should be reviewed in the field at the time of construction.

7.2 Pavement Design Parameters

Table 2 lists our recommended parameters the civil engineer can use to design the roadway subgrade and surface. Section 11.2.1.3 of the PDDM states that the resilient modulus is the primary property used for characterizing the subgrade soil. It further states that these values can be determined using correlations from a local DOT. For the purpose of this report, we have used correlations established by WisDOT between the soil type and the resilient modulus, among other properties.

Table 2: Pavement Design Parameters

Design Parameter Boring W14W Boring W14E Frost Index F-0 F-3

Design Group Index 1 12 Soil Support Value 5.4 4.2 Resilient Modulus 7000 psi 3600 psi

Modulus of Subgrade Reaction 300 pci 200 pci

8.0 CONSTRUCTION CONSIDERATIONS

8.1 Groundwater

The groundwater table will probably be encountered during installation of the culverts. The contractor is responsible for designing and implementing suitable dewatering systems. The contractor should generally not be allowed to place fill over soft, saturated soils in an attempt to displace these materials.

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN

8.2 Disturbance of Soils

The soils at this site are sensitive to disturbance and will become easily disturbed under construction traffic, especially when wet. If soils become disturbed, they should be subcut to the underlying undisturbed soils, followed by placement of new compacted fill.

8.3 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 running which could require slope maintenance.

8.4 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 met.

9.0 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, express 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.”

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN

Appendix A

Geotechnical Field Exploration and Testing

Boring Log Notes Unified Soil Classification System

Figure 1 – Boring Locations (1 of 3) Figure 2 – Boring Locations (2 of 3) Figure 3 – Boring Locations (3 of 3)

Subsurface Boring Logs Gradation Curves

SBD

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

A.1 FIELD EXPLORATION

The subsurface conditions at the site were explored by drilling five standard penetration test borings. The boring locations are shown on Figures 1, 2, and 3.

A.2 SAMPLING METHODS

A.2.1 Split-Spoon Samples (SS) Standard penetration (split-spoon) samples were collected in general accordance with ASTM: D1586. 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. After an initial set of 6 inches, the number of hammer blows to drive the sampler the next 12 inches is known as the standard penetration resistance or N-value.

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 that system. That converted energy provided what is known as an N60 blow count.

Most drill rigs today 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. We use a Pile Driving Analyzer (PDA) and an instrumented rod to measure the actual energy generated by the automatic hammer system. The drill rigs we used for this project (AET drill rig numbers 57 and 67) have measured energy transfer ratios of 89% and 90%, respectively. The N-values reported on the boring logs and the corresponding relative densities and consistencies are from the field blow counts and have not been adjusted to N60 values.

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 System (USCS). The USCS 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 USCS, 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 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.6 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.

01REP052 (12/08) AMERICAN ENGINEERING TESTING, INC.

BORING LOG NOTES

DRILLING AND SAMPLING SYMBOLS TEST SYMBOLS

Symbol Definition Symbol Definition

B, H, N: Size of flush-joint casing CA: Crew Assistant (initials) CAS: Pipe casing, number indicates nominal diameter in inches CC: Crew Chief (initials) COT: Clean-out tube DC: Drive casing; number indicates diameter in inches DM: Drilling mud or bentonite slurry DR: Driller (initials) DS: Disturbed sample from auger flights FA: Flight auger; number indicates outside diameter in inches HA: Hand auger; number indicates outside diameter HSA: Hollow stem auger; number indicates inside diameter in inches LG: Field logger (initials) MC: Column used to describe moisture condition of samples and for the ground water level symbols N (BPF): Standard penetration resistance (N-value) in blows per foot (see notes) NQ: NQ wireline core barrel PQ: PQ wireline core barrel RD: Rotary drilling with fluid and roller or drag bit REC: In split-spoon (see notes) and thin-walled tube sampling, the recovered length (in inches) of sample.

In rock coring, the length of core recovered (expressed as percent of the total core run). Zero indicates no sample recovered.

REV: Revert drilling fluid SS: Standard split-spoon sampler (steel; 1d" is inside diameter; 2" outside diameter); unless indicated otherwise

SU Spin-up sample from hollow stem auger TW: Thin-walled tube; number indicates inside diameter in inches WASH: Sample of material obtained by screening returning rotary drilling fluid or by which has collected inside the borehole after “falling” through drilling fluid

WH: Sampler advanced by static weight of drill rod and 140-pound hammer

WR: Sampler advanced by static weight of drill rod

94mm: 94 millimeter wireline core barrel ▼: Water level directly measured in boring

�: Estimated water level based solely on sample appearance

CONS: One-dimensional consolidation test DEN: Dry density, pcf DST: Direct shear test E: Pressuremeter Modulus, tsf HYD: Hydrometer analysis LL: Liquid Limit, % LP: Pressuremeter Limit Pressure, tsf OC: Organic Content, % PERM: Coefficient of permeability (K) test; F - Field;

L - Laboratory PL: Plastic Limit, % qp: Pocket Penetrometer strength, tsf (approximate) qc: Static cone bearing pressure, tsf qu: Unconfined compressive strength, psf R: Electrical Resistivity, ohm-cms RQD: Rock Quality Designation of Rock Core, in percent

(aggregate length of core pieces 4" or more in length as a percent of total core run)

SA: Sieve analysis TRX: Triaxial compression test VSR: Vane shear strength, remolded (field), psf VSU: Vane shear strength, undisturbed (field), psf WC: Water content, as percent of dry weight %-200: Percent of material finer than #200 sieve

STANDARD PENETRATION TEST NOTES

The standard penetration test consists of driving the sampler with a 140 pound hammer and counting the number of blows applied in each of three 6" increments of penetration. If the sampler is driven less than 18" (usually in highly resistant material), permitted in ASTM: D1586, the blows for each complete 6" increment and for each partial increment is on the boring log. For partial increments, the number of blows is shown to the nearest 0.1' below the slash.

The length of sample recovered, as shown on the “REC” column, may be greater than the distance indicated in the N column. The disparity is because the N-value is recorded below the initial 6" set (unless partial penetration defined in ASTM: D1586 is encountered) whereas the length of sample recovered is for the entire sampler drive (which may even extend more than 18").

01CLS021 (01/08) AMERICAN ENGINEERING TESTING, INC.

UNIFIED SOIL CLASSIFICATION SYSTEM

ASTM Designations: D 2487, D2488

AMERICAN

TESTING, INC.

Soil Classification Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Group

Symbol Group NameB

Cu>4 and 1<Cc<3E GW Well graded gravelF Clean Gravels Less than 5% finesC Cu<4 and/or 1>Cc>3E GP Poorly graded gravelF

Fines classify as ML or MH GM Silty gravelF.G.H

Gravels More than 50% coarse fraction retained on No. 4 sieve Gravels with

Fines more than 12% fines C Fines classify as CL or CH GC Clayey gravelF.G.H

Cu>6 and 1<Cc<3E SW Well-graded sandI Clean Sands Less than 5% finesD Cu<6 and 1>Cc>3E SP Poorly-graded sandI

Fines classify as ML or MH SM Silty sandG.H.I

Coarse-Grained Soils More than 50% retained on No. 200 sieve

Sands 50% or more of coarse fraction passes No. 4 sieve

Sands with Fines more than 12% fines D Fines classify as CL or CH SC Clayey sandG.H.I

PI>7 and plots on or above “A” line J

CL Lean clayK.L.M inorganic

PI<4 or plots below “A” line J

ML SiltK.L.M

Organic clayK.L.M.N

Fine-Grained Soils 50% or more passes the No. 200 sieve

(see Plasticity Chart below)

Silts and Clays Liquid limit less than 50 organic Liquid limit–oven dried <0.75

Liquid limit – not dried

OL

Organic siltK.L.M.O

PI plots on or above “A” line CH Fat clayK.L.M inorganic

PI plots below “A” line MH Elastic siltK.L.M

Organic clayK.L.M.P

Silts and Clays Liquid limit 50 or more organic Liquid limit–oven dried <0.75

Liquid limit – not dried

OH

Organic siltK.L.M.Q

Highly organic soil

Primarily organic matter, dark in color, and organic in odor

PT PeatR

3 2 ½ 1 ¾ 4 10 20 40 60 140 200

Sieve NumberScreen Opening (in.)

50 10 5 1.0 0.10.5

PARTICLE SIZE IN MILLIMETERS

SIEVE ANALYSIS

P E

R C

E N

T P

A S

S

IN

G

P E

R C

E N

T R

E

TA

IN

E

D

D60 = 15mm

D30 = 2.5mm

D10 = 0.075mm

Cu = = = 200 D60

D10

0.075

Cc = = = 5.6 (D30)

D10 x D60

2.5

0.075 x 15

2 2

CL-ML

For classification of fine-grained soils and fine-grained fraction of coarse-grained soils.

Equation of "A"-line Horizontal at PI = 4 to LL = 25.5.

then PI = 0.73 (LL-20)

Equation of "U"-line Vertical at LL = 16 to PI = 7.

then PI = 0.9 (LL-8)

"A" L

INE

"U " L

IN

E

CL O

R O

L

CH OR O

H

10 20 30 40 50 60 70 80 90 100 110 0 0

P

LA

S

TI

C

IT

Y

IN

D E

X (P

I)

LIQUID LIMIT (LL)

Plasticity Chart

Notes ABased on the material passing the 3-in (75-mm) sieve.

BIf field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name.

CGravels with 5 to 12% fines require dual symbols:

GW-GM well-graded gravel with silt GW-GC well-graded gravel with clay GP-GM poorly graded gravel with silt GP-GC poorly graded gravel with clay DSands with 5 to 12% fines require dual symbols:

SW-SM well-graded sand with silt SW-SC well-graded sand with clay SP-SM poorly graded sand with silt SP-SC poorly graded sand with clay

(D30)

ECu = D60 /D10, Cc = D10 x D60

FIf soil contains >15% sand, add “with sand” to group name.

GIf fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

HIf fines are organic, add “with organic fines” to group name.

IIf soil contains >15% gravel, add “with gravel” to group name.

JIf Atterberg limits plot is hatched area, soils is a CL-ML silty clay.

KIf soil contains 15 to 29% plus No. 200 add “with sand” or “with gravel”, whichever is predominant.

LIf soil contains >30% plus No. 200, predominantly sand, add “sandy” to group name.

MIf soil contains >30% plus No. 200, predominantly gravel, add “gravelly” to group name.

NPl>4 and plots on or above “A” line.

OPl<4 or plots below “A” line.

PPl plots on or above “A” line.

QPl plots below “A” line.

RFiber Content description shown below.

ADDITIONAL TERMINOLOGY NOTES USED BY AET FOR SOIL IDENTIFICATION AND DESCRIPTION

Grain Size Term Particle Size

Boulders Over 12" Cobbles 3" to 12" Gravel #4 sieve to 3" Sand #200 to #4 sieve Fines (silt & clay) Pass #200 sieve

Gravel Percentages Term Percent

A Little Gravel 3% - 14% With Gravel 15% - 29% Gravelly 30% - 50%

Consistency of Plastic Soils Term N-Value, BPF

Very Soft less than 2 Soft 2 - 4 Firm 5 - 8 Stiff 9 - 15 Very Stiff 16 - 30 Hard Greater than 30

Relative Density of Non-Plastic Soils Term N-Value, BPF

Very Loose 0 - 4 Loose 5 - 10 Medium Dense 11 - 30 Dense 31 - 50 Very Dense Greater than 50

Moisture/Frost Condition (MC Column)

D (Dry): Absense of moisture, dusty, dry to touch.

M (Moist): Damp, although free water not visible. Soil may still have a high water content (over “optimum”).

W (Wet/ Free water visible intended to Waterbearing): describe non-plastic soils.

Waterbearing usually relates to sands and sand with silt.

F (Frozen): Soil frozen

Layering Notes

Laminations: Layers less than ½" thick of differing material or color.

Lenses: Pockets or layers greater than ½" thick of differing material or color.

Peat Description

Fiber Content Term (Visual Estimate)

Fibric Peat: Greater than 67% Hemic Peat: 33 – 67% Sapric Peat: Less than 33%

Organic Description (if no lab tests) Soils are described as organic, if soil is not peat and is judged to have sufficient organic fines content to influence the Liquid Limit properties.

Slightly organic used for borderline cases.

Root Inclusions With roots: Judged to have sufficient quantity of roots to influence the soil properties.

Trace roots: Small roots present, but not judged to be in sufficient quantity to significantly affect soil properties.

1550 15

A

C

FR 383

FR 194

FR

3B A

C O

FF

EE

LA

K E

LN

FR

8D

WISCO RD

FR 383B

FR

A

FR

FR 614

W

IS

CO

RD

FOREST RD

CHEQUAMEGON

NATIONAL FOREST

M arengo

R iver

W hi sk y

C

Coffee Lake

Boring W14E

Boring S6

Figure 1 - Boring Locations (1 of 3)

D

198FR 202E

WISCO

RD

FR

FOREST RD 377

CAMP EIGHT RD

W

ISCO RD

ATKIN

FR 202B

O

LD

G

RA

D E

R D

FR 202A

FR

FR 201

M ar en go

R iv er

Twentymile Cr

Atkins Lake

30"

17'

Boring W14W

Figure 2 - Boring Locations (2 of 3)

F

1400 1400

N

OLE

LAKE

RD

N N

EU

M

A

IE

R R

D

M O

RG

AN

RD

W

EL

EP

H

A N

T R

O C

K R

DBRANDT RD

TR

APPE RD

N

RE

D D

EE

R

R D

UPPER

A

RD

T R

A

IL

S

EN

D

LN

UPPER A RD

WILSON

BAY

D R

TE

W

S

RD

Wilson Cr

Ole Cr

Stearns Lake

Davis Lake

Ole Lake

Lost Land Lake

Holmes Lake Wilson

Lake is e

Little Ole Lake

Beaver Lake

91°

40 6

6 41 680 446 42 6

6 000 FEET

10'

5'

46°

30"

FEET

07'

SPIDER LAKE QUADRANGLE

WISCONSIN-SAWYER CO.

7.5-MINUTE SERIES

Boring S10

Boring S11

Figure 3 - Boring Locations (3 of 3)

FILL, silty sand with gravel, fine to medium grained, brown, frozen to moist

(SM)

FILL, silty sand with organics (roots), fine grained, a little gravel, brown, moist

(SM)

SILTY SAND with gravel, fine to medium grained, brown, moist to waterbearing, medium dense to very dense (SM)

SAND with gravel, fine to medium grained, brown, waterbearing, very dense (SP)

Gravelly SAND WITH SILT, fine to coarse grained, brown, waterbearing, dense to very dense (SP-SM)

SAND with gravel, fine to coarse grained, brown, waterbearing, medium dense (SP)

-- rock stuck in tip of sampler

GRAVEL with sand, brown, waterbearing, medium dense (GP)

SAND with gravel, fine to coarse grained, brown, waterbearing, loose (SP)

SAND WITH SILT and gravel, fine to coarse grained, brown, waterbearing, loose (SP-SM)

Gravelly SILTY SAND, fine to coarse grained, brown, waterbearing, medium dense (SM) End of boring at 31.5 feet Surface elevation assumed/estimated based on pre-flood design drawing

98.5

96.0

91.0

88.5

83.5

81.0

78.5

76.0

73.5

71.0

69.0

50/.4

91/.9

FILL

TILL

COARSE

ALLUVIUM

TILL

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

F/M

M

M

M/W

W

W

W

W

W

W

W

W

CAVE-IN

DEPTH

CASING

DEPTH

SAMPLED

DEPTH

12/20/17

12/20/17

TIME

DRILLING METHOD

12/20/17

3.25" HSA

w/DM

DATE

11.5'

11.5'

DEPTH:

DRILLING

FLUID LEVEL

BORING

COMPLETED:

LG: 57

WATER

LEVEL

DR:

NOTE: REFER TO

THE ATTACHED

SHEETS FOR AN

EXPLANATION OF

TERMINOLOGY ON

THIS LOG

Rig:

8.9'

8.9'

MD

0-9.5'

9.5-29.5'

Surface Elevation 100.5

None

None

9.5'

9.5'

WATER LEVEL MEASUREMENTS

8.5'

8.2'

LL

12-02938

01-DHR-060

ELEV.

FEET GEOLOGY

AMERICAN

ENGINEERING

TESTING, INC.

MC

MATERIAL DESCRIPTION

REC

IN. PLWC

DEPTH

IN

FEET

S6 (p. 1 of 1)

03/2011

AET No:

Project: WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest qp %-#200

FIELD & LABORATORY TESTS

SAMPLE

TYPEN

LL

SUBSURFACE BORING LOG

Log of Boring No.

A E

T _C

O R

P W

-E

LE

V

2-

8.

G P

J A

E T

C

P T

W

E

LL

.G D

T

/2 1/

GRAVEL with sand, brown, frozen to moist (GW)

Gravelly SAND, fine to coarse grained, brown, wet, medium dense (SP)

SAND with gravel, fine to medium grained, brown, wet, dense to very dense

(SP)

Gravelly SILTY SAND, fine to coarse grained, brown and gray, moist, very dense (SM) CLAYEY GRAVEL with sand, dark gray, waterbearing, very dense (GC) End of boring at 12.5 feet Arbitrary surface elevation of 100.0 feet selected for graphical purposes

98.0

95.5

90.0

88.0 87.5

50/.4

72/.3

50/.4

COARSE

ALLUVIUM

TILL

SS

SS

SS

SS

SS

SS

F/M

M/W

W

M

W

CAVE-IN

DEPTH

CASING

DEPTH

SAMPLED

DEPTH

12/21/17

12/21/17

TIME

DRILLING METHOD

12/20/17

3.25" HSA

DATE

6.5'

6.5'

DEPTH:

DRILLING

FLUID LEVEL

BORING

COMPLETED:

LG: 57

WATER

LEVEL

DR:

NOTE: REFER TO

THE ATTACHED

SHEETS FOR AN

EXPLANATION OF

TERMINOLOGY ON

THIS LOG

Rig:

4.5'

4.5'

MD

0-12.5'

Surface Elevation 100.0

None

None

4.5'

4.5'

WATER LEVEL MEASUREMENTS

2.5'

2.4'

LL

12-02938

01-DHR-060

ELEV.

FEET GEOLOGY

AMERICAN

ENGINEERING

TESTING, INC.

MC

MATERIAL DESCRIPTION

REC

IN. PLWC

DEPTH

IN

FEET

W14W (p. 1 of 1)

03/2011

AET No:

Project: WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest qp %-#200

FIELD & LABORATORY TESTS

SAMPLE

TYPEN

LL

SUBSURFACE BORING LOG

Log of Boring No.

A E

T _C

O R

P W

-E

LE

V

2-

8.

G P

J A

E T

C

P T

W

E

LL

.G D

T

/2

SILTY SAND, fine grained, a little gravel, brown, frozen to moist (SM) SILTY SAND, fine grained, brown, moist, loose (SM)

Gravelly SILTY SAND, fine to coarse grained, brown, moist to waterbearing, medium dense to very dense (SM)

GRAVEL (rock chips) with sand, dark gray, waterbearing, very dense (GP) Auger refusal at 12.4 feet Arbitrary surface elevation of 100.0 feet selected for graphical purposes

99.0

93.0

88.0 87.6

90/.6

50/.4

COARSE

ALLUVIUM DS

SS

SS

SS

SS

SS

F/M

M

M

M/W

W

W

CAVE-IN

DEPTH

CASING

DEPTH

SAMPLED

DEPTH

12/21/17

12/21/17

TIME

DRILLING METHOD

12/21/17

3.25" HSA

DATE

12.4'

12.4'

DEPTH:

DRILLING

FLUID LEVEL

BORING

COMPLETED:

LG: 57

WATER

LEVEL

DR:

NOTE: REFER TO

THE ATTACHED

SHEETS FOR AN

EXPLANATION OF

TERMINOLOGY ON

THIS LOG

Rig:

11.8'

11.8'

MD

0-12.4'

Surface Elevation 100.0

None

None

12.0'

12.0'

WATER LEVEL MEASUREMENTS

9.0'

8.8'

LL

12-02938

01-DHR-060

ELEV.

FEET GEOLOGY

AMERICAN

ENGINEERING

TESTING, INC.

MC

MATERIAL DESCRIPTION

REC

IN. PLWC

DEPTH

IN

FEET

W14E (p. 1 of 1)

03/2011

AET No:

Project: WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest qp %-#200

FIELD & LABORATORY TESTS

SAMPLE

TYPEN

LL

SUBSURFACE BORING LOG

Log of Boring No.

A E

T _C

O R

P W

-E

LE

V

2-

8.

G P

J A

E T

C

P T

W

E

LL

.G D

T

/2

FILL, silty gravel with sand, brown, frozen (GM)

FILL, silty sand with gravel, fine to coarse grained, brown, frozen to moist to waterbearing (SM)

WOOD (possible fill)

SILTY SAND, fine to medium grained, a little gravel, brown, waterbearing, with some pieces of wood, possible fill (SM) SAPRIC PEAT with sand, a little gravel, dark brown, waterbearing (PT) SAPRIC PEAT, dark brown, waterbearing (PT) SAND WITH SILT, fine to medium grained, a little gravel, brown, waterbearing, very loose (SP-SM) SAND, fine to medium grained, brown, waterbearing, very loose to loose (SP)

SAND WITH SILT, fine to medium grained, a little gravel, brown, waterbearing, loose (SP-SM)

SILTY SAND, fine grained, brown, waterbearing, medium dense (SM)

SILTY SAND, fine to medium grained, a little gravel, brown, waterbearing, loose to medium dense (SM)

End of boring at 31.5 feet

1396.8

1391.8

1389.3

1388.3

1386.8

1385.3

1384.3

1379.3

1376.8

1374.3

1367.3

50/.4

FILL

WOOD

COARSE

ALLUVIUM

SWAMP

DEPOSITS

COARSE

ALLUVIUM

TILL

DS

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

F

F/M

M

W

W

W

W

W

W

W

W

W

W

CAVE-IN

DEPTH

CASING

DEPTH

SAMPLED

DEPTH

12/20/17

12/20/17

TIME

DRILLING METHOD

12/20/17

3.25" HSA

w/DM

DATE

14.0'

14.0'

DEPTH:

DRILLING

FLUID LEVEL

BORING

COMPLETED:

LG: 67

WATER

LEVEL

DR:

NOTE: REFER TO

THE ATTACHED

SHEETS FOR AN

EXPLANATION OF

TERMINOLOGY ON

THIS LOG

Rig:

11.8'

11.0'

GM

0-12.0'

12.0-29.5'

Surface Elevation 1398.8

None

None

12.0'

12.0'

WATER LEVEL MEASUREMENTS

8.1'

6.6'

MH

12-02938

01-DHR-060

ELEV.

FEET GEOLOGY

AMERICAN

ENGINEERING

TESTING, INC.

MC

MATERIAL DESCRIPTION

REC

IN. PLWC

DEPTH

IN

FEET

S10 (p. 1 of 1)

03/2011

AET No:

Project: WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest qp %-#200

FIELD & LABORATORY TESTS

SAMPLE

TYPEN

LL

SUBSURFACE BORING LOG

Log of Boring No.

A E

T _C

O R

P W

-E

LE

V

2-

8.

G P

J A

E T

C

P T

W

E

LL

.G D

T

/2

FILL, silty sand with gravel, fine to medium grained, brown, frozen (SM)

FILL, sand with gravel, fine to medium grained, brown, moist (SP)

SILTY SAND, fine to medium grained, a little gravel, trace organics (roots and pieces of wood) brown, moist, loose

(SM)

SILTY SAND, fine to medium grained, a little gravel, brown, waterbearing, loose to medium dense (SM)

SILTY SAND, fine grained, a little gravel, brown, waterbearing, loose (SM)

SILTY SAND, fine to medium grained, a little gravel, brown, waterbearing, loose to medium dense (SM)

End of boring at 31.5 feet

1398.6

1396.1

1393.6

1378.6

1376.1

1369.1

FILL

COARSE

ALLUVIUM

TILL

DS

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

SS

F

M

M

W

W

W

W

W

W

W

W

W

W

CAVE-IN

DEPTH

CASING

DEPTH

SAMPLED

DEPTH

12/20/17

12/20/17

TIME

DRILLING METHOD

12/20/17

3.25" HSA

DATE

31.5'

31.5'

DEPTH:

DRILLING

FLUID LEVEL

BORING

COMPLETED:

LG: 67

WATER

LEVEL

DR:

NOTE: REFER TO

THE ATTACHED

SHEETS FOR AN

EXPLANATION OF

TERMINOLOGY ON

THIS LOG

Rig:

27.5'

26.7'

GM

0-29.5'

Surface Elevation 1400.6

None

None

29.5'

29.5'

WATER LEVEL MEASUREMENTS

26.9'

23.7'

MH

12-02938

01-DHR-060

ELEV.

FEET GEOLOGY

AMERICAN

ENGINEERING

TESTING, INC.

MC

MATERIAL DESCRIPTION

REC

IN. PLWC

DEPTH

IN

FEET

S11 (p. 1 of 1)

03/2011

AET No:

Project: WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest qp %-#200

FIELD & LABORATORY TESTS

SAMPLE

TYPEN

LL

SUBSURFACE BORING LOG

Log of Boring No.

A E

T _C

O R

P W

-E

LE

V

2-

8.

G P

J A

E T

C

P T

W

E

LL

.G D

T

/2

0.0010.010.1110100

D10 coarse

4 14081.5 6 200100

GRAIN SIZE IN MILLIMETERS

Specimen Identification

Specimen Identification

MC%

3/4 30 medium

LL PL PI Cc

SILT OR CLAY

GRADATION CURVES

19.6

46.4

%Sand %Silt %Clay

76.3

46.8

%Gravel

SAND

fine

U.S. SIEVE NUMBERS

20161410

U.S. SIEVE OPENING IN INCHES HYDROMETER

6.3

52.3

0.57

0.63

S6

S6

10.5'

13.0'

10.5'

13.0'

S6

S6

1/2

0.99

6.23

P E R C E N T

F I N E R

B Y

W E I G H T

Sand with gravel, f-m grained (SP)

Gravelly sand with silt, f-c grained (SP-SM)

3/8

25.00

37.50

Classification Cu

D100

6 70504

GRAVEL

fine

COBBLES

coarse

0.1567

0.1191

4.2

6.8

D60 D30

0.297

0.684

12/20/17 WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest

PROJECT AET JOB NO.

DATE

12-02938

AMERICAN

0.0010.010.1110100

D10 coarse

4 14081.5 6 200100

GRAIN SIZE IN MILLIMETERS

Specimen Identification

Specimen Identification

MC%

3/4 30 medium

LL PL PI Cc

SILT OR CLAY

GRADATION CURVES

7.2

0.0

59.1

46.1

%Sand %Silt %Clay

69.4

84.7

36.9

50.6

%Gravel

SAND

fine

U.S. SIEVE NUMBERS

20161410

U.S. SIEVE OPENING IN INCHES HYDROMETER

40.1

46.5

1.70

0.25

W14E

W14E

W14W

W14W

0.5'

1.5'

1.0'

5.5'

0.5'

1.5'

1.0'

5.5'

W14E

W14E

W14W

W14W

1/2

0.15

0.19

10.57

8.88

P E R C E N T

F I N E R

B Y

W E I G H T

Silty sand, f grained, a little gravel (SM)

Silty sand, f grained (SM)

Gravel with sand (GW)

Gravelly sand, f-c grained (SP)

3/8

19.00

4.75

25.00

37.50

Classification Cu

D100

6 70504

GRAVEL

fine

COBBLES

coarse

0.2639

0.1910

23.5

15.3

4.1

3.3

D60 D30

0.085

0.101

2.178

0.647

12/20/17 WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest

PROJECT AET JOB NO.

DATE

12-02938

AMERICAN

Photo 1: Boring S6

Photo 2: Boring S6 – Sample from 9.5 to 12 feet

Photo 3: Boring W14W – Sample from 0 to 2 feet

Photo 4: Boring W14W – Sample from 12 to 12.5 feet

Photo 5: Boring W14E

Photo 6: Boring W14E – Sample from 12 to 12.4 feet

Photo 7: Boring S10

Photo 8: Boring S10 – Sample from 7 to 9 feet

Photo 9: Boring S11

Photo 10: Boring S11 – Sample from 17 to 19 feet

WI ERFO FS 2016-1(2); Chequamegon-Nicolet National Forest AMERICAN

Appendix B

Geotechnical Report Limitations and Guidelines for Use

Appendix B – Page 1 of 2 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 Geotechnical Services are Performed for Specific Purposes, Persons, and Projects Geotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical engineering study conducted for a civil engineer may not fulfill the needs of a construction contractor or even another civil engineer. Because each geotechnical engineering study is unique, each geotechnical engineering report is unique, prepared solely for the client.

No one except you should rely on your geotechnical engineering report without first conferring with the geotechnical engineer who prepared it. And no one, not even you, should apply the report for any purpose or project except the one originally contemplated.

B.2.2 Read the Full Report Serious problems have occurred because those relying on a geotechnical engineering report did not read it all. Do not rely on an executive summary. Do not read selected elements only.

B.2.3 A Geotechnical Engineering Report is Based on A Unique Set of Project-Specific Factors Geotechnical engineers consider a number of unique, project-specific factors when establishing the scope of a study. Typically, factors include: the client’s goals, objectives, and risk management preferences; the general nature of the structure involved, its size, and configuration; the location of the structure on the site; and other planned or existing site improvements, such as access roads, parking lots, and underground utilities. Unless the geotechnical engineer who conducted the study specifically indicates otherwise, do not rely on a geotechnical engineering report that was:

• not prepared for you,

• not prepared for your project,

• not prepared for the specific site explored, or

• completed before important project changes were made.

Typical changes that can erode the reliability of an existing geotechnical engineering report include those that affect:

• the function of the proposed structure, as when it’s changed from a parking garage to an office building, or from a light industrial plant to a refrigerated warehouse,

• elevation, configuration, location, orientation, or weight of the proposed structure,

• composition of the design team, or

• project ownership.

As a general rule, always inform your geotechnical engineer of project changes, even minor ones, and request an assessment of their impact. Geotechnical engineers cannot accept responsibility or liability for problems that occur because their reports do not consider developments of which they were not informed.

B.2.4 Subsurface Conditions Can Change A geotechnical engineering report is based on conditions that existed at the time the study was performed. Do not rely on a geotechnical engineering report whose adequacy may have been affected by: the passage of time; by man-made events, such as construction on or adjacent to the site; or by natural events, such as events, earthquakes, or groundwater fluctuations. Always contact the geotechnical engineer before applying the report to determine if it is still reliable. A minor amount of additional testing or analysis could prevent major problems.

1 Geoprofessional Business Association, 1300 Piccard Drive, LL14, Rockville, MD 20850 Telephone: 301/565-2733: www.geoprofessional.org

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

B.2.5 Most Geotechnical Findings Are Professional Opinions Site exploration identified subsurface conditions only at those points where subsurface tests are conducted or samples are taken.

Geotechnical engineers review field and laboratory data and then apply their professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ, sometimes significantly, from those indicated in your report. Retaining the geotechnical engineer who developed your report to provide construction observation is the most effective method of managing the risks associated with unanticipated conditions.

B.2.6 A Report’s Recommendations Are Not Final Do not over-rely on the construction recommendations included in your report. Those recommendations are not final, because geotechnical engineers develop them principally from judgment and opinion. Geotechnical engineers can finalize their recommendations only by observing actual subsurface conditions revealed during construction. The geotechnical engineer who developed your report cannot assume responsibility or liability for the report’s recommendations if that engineer does not perform construction observation.

B.2.7 A Geotechnical Engineering Report Is Subject to Misinterpretation Other design team members’ misinterpretation of geotechnical engineering reports has resulted in costly problems. Lower that risk by having your geotechnical engineer confer with appropriate members of the design team after submitting the report. Also retain your geotechnical engineer to review pertinent elements of the design team’s plans and specifications. Contractors can also misinterpret a geotechnical engineering report. Reduce that risk by having your geotechnical engineer participate in prebid and preconstruction conferences, and by providing construction observation.

B.2.8 Do Not Redraw the Engineer’s Logs Geotechnical engineers prepare final boring and testing logs based upon their interpretation of field logs and laboratory data.

To prevent errors or omissions, the logs included in a geotechnical engineering report should never be redrawn for inclusion in architectural or other design drawings. Only photographic or electronic reproduction is acceptable, but recognizes that separating logs from the report can elevate risk.

B.2.9 Give Contractors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give contractors the complete geotechnical engineering report, but preface it with a clearly written letter of transmittal. In the letter, advise contractors that the report was not prepared for purposes of bid development and that the report’s accuracy is limited; encourage them to confer with the geotechnical engineer who prepared the report (a modest fee may be required) and/or to conduct additional study to obtain the specific types of information they need or prefer. A prebid conference can also be valuable. Be sure contractors have sufficient time to perform additional study. Only then might you be in a position to give contractors the best information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions.

B.2.10 Read Responsibility Provisions Closely Some clients, design professionals, and contractors do not recognize that geotechnical engineering is far less exact than other engineering disciplines. This lack of understanding has created unrealistic expectations that have led to disappointments, claims, and disputes.