SW3190701_Soils Report_20190708

Lrdvark
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June 27, 2019
Mr. Mitch Latham
Latham -Walters Engineering, Inc.
16507-A Northcross Drive
Huntersville, NC 28078
Reference: SUMMARY OF GEOTECHNICAL EXPLORATION
Groundwater Study for SHWT Design
Harwood Automotive Expansion
Midland, North Carolina
Dear Mr. Latham:
Submitted herewith is the summary of our geotechnical exploration for the referenced project. This study was conducted in
accordance with your email and verbal authorization.
PURPOSE AND SCOPE
The purpose of this study was to evaluate the general subsurface conditions for the seasonal high water table at the
referenced skimmer basin location. Subsurface conditions at this project site were evaluated by drilling total of two (2) soil
borings each located at the proposed sediment basins.
FIELD PROCEDURES
Subsurface conditions at this project site were evaluated by drilling total of two (2) soil borings located at the proposed
skimmer basin. The field exploration was performed on June 14, 2019 and monitored for groundwater until June 21, 2019.
Due to methods used, the location and elevations of the borings should be considered approximate.
The hand auger borings were made by manually twisting a post -hole auger into the soil. The auger consisted of a two
curved blades and a bucket which retains the soil as the auger is advanced. Water levels were measured upon completion
and at subsequent days after drilling. Our staff engineer coordinated our field activities, conducted the reconnaissance of
the site, and prepared the report of the subsurface conditions encountered.

aardvark
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SUBSURFACE SOIL CONDITIONS
Our interpretation of the subsurface conditions is based upon a review of available published literature and the widely
spaced soil borings. The following is a generalized discussion of our findings.
Approximately 4 to 6 inches of topsoil was encountered at each soil boring location. Below the surface materials at the
test locations, residual soils were encountered to the depths explored. The residual soils typically consisted of stiff to very
stiff sandy silty with fragment rock to the depths explored. Each boring location encountered auger refusal within dense
residual soils at depths of approximately 6 feet (Elev. 523 feet per the site plan) below the existing ground surface.
GROUNDWATER CONDITIONS
The term groundwater, for the purpose of this report, pertains to any water that percolates through the naturally occurring
materials found on site. This includes any overland flow that permeates through a given depth of soil, perched water, and
water that occurs below the water table, a zone that remains saturated and water bearing year round.
Groundwater was not encountered at each of the boring locations during our evaluation. The borings were checked for
groundwater from June 14 to June 21, 2019. It should be recognized that fluctuations in the groundwater level should be
expected to occur due to variations in rainfall and other environmental or physical factors at the time measurements are
made. Slightly elevated groundwater conditions should be expected during wetter periods of the year, especially within
sandy soil layers or above clay soils.
CONCLUSIONS
Groundwater was not encountered at each of our boring locations during our evaluation. Based on the findings of our
exploration and elevations provided on the Erosion Control Plan sheet C-03 dated April 29, 2019, it is our opinion that the
season high water table is at a depth greater than 3 feet below the proposed elevation for the bottom of the proposed
skimmer basin.
338 South Sharon Amity Road #135 www.aardvarkengineers.com Phone [phone]
Charlotte, North Carolina 28211 Fax [phone]

aardvark
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LIMITATIONS OF STUDY
The recommendations provided herein were developed from the information obtained in our sampling, which depicts
general subsurface conditions only at specific locations. Subsurface conditions at other locations may differ from those
occurring at the specific excavation sites.
The nature and extent of variations between sampling locations may not become evident until the course of construction.
If variations then become evident, it will be necessary to re-evaluate the recommendations of this report after performing
on -site observations during the excavation and noting the characteristics of any variation.
Our professional services have been performed, findings obtained, and recommendations prepared in accordance with
generally accepted geotechnical engineering principles and practices. No warranties are either expressed or implied.
Field observations, monitoring, and quality assurance testing during earthwork and foundation installation are an extension
of the geotechnical design. We recommend that the owner retain these services and that we be allowed to continue our
involvement in the project through these phases of construction. Our firm is not responsible for interpretation of the data
contained in this report by others, nor do we accept any responsibility for job site safety which is the sole responsibility of
the contractor.
We appreciate the opportunity to be of service to you on this project. If we can be of further assistance, or if you have any
questions regarding this report, please contact our office.
Regards,
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Kevin C. McTier, P.E.
029409
Senior Geotechnical Engineer
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NC Registration 029409
NC COA C-3319
6/27/2019
338 South Sharon Amity Road #135 www.aardvarkengineers.com Phone [phone]
Charlotte, North Carolina 28211 Fax [phone]

aardvark
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GENERAL QUALIFICATIONS
This report has been prepared at the request of our client for their use on this project. The work, including the field work, laboratory
testing, and engineering analysis, was performed in accordance with generally accepted soil and foundation engineering practices. This
warranty is in lieu of all other warranties either expressed or implied.
This report may not contain sufficient information for purposes of other parties or other uses. Should there be any sufficient
differences in structural arrangement, loading or location of the structure, our analysis should be reviewed.
The analysis, conclusions, and recommendations contained in our report are based on site conditions as they existed at the time of our
exploration and further assume that the borings are representative of the subsurface conditions throughout the site.
If during construction, different subsurface conditions from those encountered during our explorations are observed or appear to be
present beneath excavations, we must be advised promptly so that we can review these conditions and reconsider our
recommendations where necessary.
If there is a substantial lapse of time between the submission of our report and the start of work at the site, or if conditions have
changed due to natural causes or construction operations at or adjacent to the site, we urge that our report be reviewed to determine
the applicability of the conclusions and recommendations considering the changed conditions and time lapse.
We urge that we be retained to review those portions of the plans and specifications that pertain to earthwork and foundations to
determine whether they are consistent with our recommendations. In addition, we are available to observe construction, particularly
the compaction of structural backfill and preparation of the foundations, and such other field observations as may be necessary.
In order to fairly consider changed or unexpected conditions that might arise during construction, we recommend the following
verbiage (Standard Clause for Unanticipated Subsurface Conditions) be included in the project contract.
STANDARD CLAUSE FOR UNANTICIPATED SUBSURFACE CONDITIONS
"The owner has had a subsurface exploration performed by a soils consultant, the results of which are contained in the consultant's
report. The consultant's report represents their conclusions on the subsurface conditions based on their interpretations of the data
obtained in the exploration. The contractor acknowledges that they have reviewed the consultant's report and any addenda thereto,
and that their bid for earthwork operations is based on the subsurface conditions as described in that report. It is recognized that a
subsurface exploration may not disclose all conditions as they actually exist and further, conditions may change, particularly
groundwater conditions, between the time of a subsurface exploration and the time of earthwork operations. In recognition of these
facts, this clause is entered in the contract to provide a means of equitable additional compensation for the contractor if adverse
unanticipated conditions are encountered and to provide a means of rebate to the owner if the conditions are more favorable than
anticipated.
At anytime during construction operations that the contractor encounters conditions that are different than those anticipated by the
soils consultant's report, they shall immediately (within 24 hours) bring this fact to the owner's attention. If the owner's representative
on the construction site observes subsurface conditions which are different than those anticipated by the consultant's report, they shall
immediately (within 24 hours) bring this fact to the contractor's attention. Once a fact of unanticipated conditions has been brought to
the attention of either the owner or the contractor, and the consultant has concurred, immediate negotiations will be undertaken
between the owner and the contractor, to arrive at a change in contract price for additional work or reduction in work because of the
unanticipated conditions. The contractor agrees that the following unit prices would apply for additional or reduced work under the
contract. For changed conditions for which unit prices are not provided, the additional work shall be paid for on a time and materials
basis."
Another example of a changed conditions clause can be found in paper No. 4035 by Robert F. Borg, published in ASCE Construction
Division Journal, No. CO2, September 1964, page 37.
338 South Sharon Amity Road #135 www.aardvarkengineers.com Phone [phone]
Charlotte, North Carolina 28211 Fax [phone]