Draft Geo Evaluation Report - Klingelhutz Property - B1611559
Geotechnical Evaluation Report
Klingelhutz Property
8601 Great Plains Boulevard
Chanhassen, Minnesota
Prepared for
PulteGroup, Inc.
Professional Certification:
I hereby certify that this plan, specification, or report
was prepared by me or under my direct supervision
and that I am a duly Licensed Professional Engineer
under the laws of the State of Minnesota.
Erik C. Johnson, PE
Associate Principal – Project Engineer
License Number: 49817
April 26, 2017
Project B1611559
Braun Intertec Corporation DRAFT
AA/EOE
Braun Intertec Corporation
11001 Hampshire Avenue S
Minneapolis, MN 55438
Phone: 952.995.2000
Fax: 952.995.2020
Web: braunintertec.com
April 26, 2017 Project B1611559
Mr. Paul Heuer
PulteGroup, Inc.
7500 Office Ridge Circle, Suite 325
Eden Prairie, MN 55344
Re: Geotechnical Evaluation
Klingelhutz Property
8601 Great Plains Boulevard
Chanhassen, Minnesota
Dear Mr. Heuer:
We are pleased to present this Geotechnical Evaluation Report for the Klingelhutz Property residential
development on the property at Waters Edge Drive and Lake Susan Drive in Chanhassen, Minnesota. The
purpose of our evaluation was to assist you and your design team in evaluating subsurface soil and
groundwater conditions with regard to design and construction of the new residential housing
development. Please read the entire attached report for details regarding our findings and
recommendations.
Thank you for making Braun Intertec your geotechnical consultant for this project. If you have questions
about this report, or if there are other services that we can provide in support of our work to date, please
contact Erik Johnson at 952.995.2426 (ejohnson@braunintertec.com) or Henry Vloo at 952.995.2234
(hvloo@braunintertec.com).
Sincerely,
BRAUN INTERTEC CORPORATION
Erik C. Johnson, PE
Associate Principal – Project Engineer
Henry Vloo, PE
Associate Principal – Senior Engineer
DRAFT
Table of Contents
Description Page
A. Introduction ...................................................................................................................................... 1
A.1. Project Description .............................................................................................................. 1
A.2. Site Conditions and History ................................................................................................. 1
A.3. Purpose ................................................................................................................................ 1
A.4. Background Information and Reference Documents .......................................................... 2
A.5. Scope of Services ................................................................................................................. 2
B. Results .............................................................................................................................................. 3
B.1. Geologic Overview .............................................................................................................. 3
B.2. Boring Results ...................................................................................................................... 3
B.3. Groundwater ....................................................................................................................... 5
B.4. Laboratory Test Results ....................................................................................................... 5
C. Recommendations ........................................................................................................................... 6
C.1. Design and Construction Discussion ................................................................................... 6
C.1.a. Building Subgrade Preparation .............................................................................. 6
C.1.b. Existing Fill .............................................................................................................. 6
C.1.c. Reuse of On-Site Soils ............................................................................................. 7
C.1.d. Effects of Groundwater .......................................................................................... 7
C.2. Site Grading and Subgrade Preparation .............................................................................. 7
C.2.a. Building Subgrade Excavations ............................................................................... 7
C.2.b. Excavation Oversizing ............................................................................................. 8
C.2.c. Excavated Slopes .................................................................................................... 9
C.2.d. Excavation Dewatering ........................................................................................... 9
C.2.e. Selecting Excavation Backfill and Additional Required Fill ..................................... 9
C.2.f. Pavement and Exterior Slab Subgrade Preparation ............................................... 9
C.2.g. Pavement Subgrade Proofroll .............................................................................. 10
C.2.h. Compaction Requirements ................................................................................... 10
C.3. Spread Footings ................................................................................................................. 11
C.3.a. Embedment Depth ............................................................................................... 11
C.3.b. Subgrade Improvement ....................................................................................... 11
C.3.c. Net Allowable Bearing Pressure ........................................................................... 12
C.3.d. Settlement ............................................................................................................ 12
C.4. Interior Slabs ..................................................................................................................... 12
C.4.a. Moisture Vapor Protection .................................................................................. 12
C.4.b. Radon ................................................................................................................... 12
C.5. Frost Protection ................................................................................................................. 12
C.5.a. General ................................................................................................................. 12
C.5.b. Frost Heave Mitigation ......................................................................................... 13
C.6. Pavements and Exterior Slabs ........................................................................................... 14
C.6.a. Design Sections .................................................................................................... 14
C.6.b. Bituminous Pavement Materials .......................................................................... 15
C.6.c. Subgrade Drainage ............................................................................................... 15
C.6.d. Performance and Maintenance ........................................................................... 15
C.7. Utilities .............................................................................................................................. 16
C.7.a. Subgrade Stabilization .......................................................................................... 16
C.7.b. Selection, Placement, and Compaction of Backfill ............................................... 16 DRAFT
Table of Contents (continued)
Description Page
C.7.c. Dewatering ........................................................................................................... 16
C.7.d. Corrosion Potential .............................................................................................. 16
C.8. Stormwater........................................................................................................................ 16
D. Procedures...................................................................................................................................... 17
D.1. Penetration Test Borings ................................................................................................... 17
D.2. Exploration Logs ................................................................................................................ 17
D.2.a. Log of Boring Sheets ............................................................................................. 17
D.2.b. Geologic Origins ................................................................................................... 18
D.3. Material Classification and Testing ................................................................................... 18
D.3.a. Visual and Manual Classification .......................................................................... 18
D.3.b. Laboratory Testing ............................................................................................... 18
D.4. Groundwater Measurements ............................................................................................ 18
E. Qualifications .................................................................................................................................. 18
E.1. Variations in Subsurface Conditions .................................................................................. 18
E.1.a. Material Strata ..................................................................................................... 18
E.1.b. Groundwater Levels ............................................................................................. 19
E.2. Continuity of Professional Responsibility .......................................................................... 19
E.2.a. Plan Review .......................................................................................................... 19
E.2.b. Construction Observations and Testing ............................................................... 19
E.3. Use of Report..................................................................................................................... 20
E.4. Standard of Care ................................................................................................................ 20
Appendix A – North Site
Soil Boring Location Sketch
Log of Boring Sheets ST-1 through ST-7
Descriptive Terminology of Soil
Appendix B – South Site
Soil Boring Location Sketch – Haugo Geotechnical Services 2013
Log of Previous Boring Sheets SB-1 through SB-4 – Haugo Geotechnical Services 2013 DRAFT
A. Introduction
A.1. Project Description
PulteGroup, Inc. is planning to develop a 10-acre site located to the east of the intersection of Waters
Edge Drive and Lake Susan Drive. The proposed development will consist of 13 townhouse buildings with
65 units in the northern property and 4 townhouse buildings with 21 units in the southern property. The
development will also include the construction of the associated streets, underground utilities, and two
stormwater ponds. The preliminary house types as well as garage and first floor elevations were not
available at the time of this report. We understand all buildings will be slab on grade.
We assume the construction will consist of 2-story wood framed houses with pitched roofs, on poured
concrete foundations. We have assumed that bearing wall loads associated with the proposed residential
construction will range from 3 to 4 kips (3,000 to 4,000 pounds) per linear foot (klf) and column loads, if
any, will be no greater than 50 kips per column.
A.2. Site Conditions and History
The two parcels of land are located east of Waters Edge Drive, one on each the north and south sides of
Lake Susan Drive. Both parcels are immediately north of US Highway 212.
Currently, both parcels consist of two empty grass fields with a farm site in the north half of the northern
property. Based on the recorded survey, site elevations for the north parcel range from about 903 to
917 feet Mean Sea Level (MSL), generally sloping downward across the southern portion of the site. The
elevations of the south parcel generally range from about 907 to 910 MSL.
Site grading occurred on the southern portion of the north parcel in 2008. Braun Intertec performed
excavation observations and compaction testing during site grading. A Summary Report of Excavation
Observations and Compaction Testing can be found under Braun Intertec project number BL-08-01881,
dated October 6, 2008.
A.3. Purpose
The purpose of a geotechnical Evaluation is to characterize subsurface geologic conditions at selected
exploration locations and evaluate their impact on the design and construction of the proposed
residential development.
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PulteGroup Inc.
Project B1611559
April 26, 2017
Page 2
A.4. Background Information and Reference Documents
We reviewed the following information:
Available public aerial photographs showing the existing and historical site conditions.
A provided Concept Sketch Plan, prepared by Alliant Engineering, dated February 2, 2017.
Previous Summary Report of Excavation Observations and Compaction Testing, prepared by
Braun Intertec, dated October 6, 2008.
Previous soil boring information that was completed on the south parcel by Haugo
GeoTechnical Services under project number 13-354.
Geologic atlas showing the general soil types present in this area.
We have described our understanding of the proposed construction and site to the extent others
reported it to us. Depending on the extent of available information, we may have made assumptions
based on our experience with similar projects. If we have not correctly recorded or interpreted the
project details, the project team should notify us. New or changed information could require additional
evaluation, analyses and/or recommendations.
A.5. Scope of Services
We performed our scope of services for the project in accordance with our Revised Proposal to
PulteGroup, Inc., dated February 8, 2017. The following list describes the geotechnical tasks completed in
accordance with our authorized scope of services.
Reviewing the background information and reference documents previously cited.
Coordinating the clearing of the exploration locations of public underground utilities.
Performing seven standard penetration test (SPT) borings, denoted as ST-1 to ST-7, to
nominal depths of 15 to 20 feet below grade across the north parcel.
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Project B1611559
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Performing laboratory testing on select samples to aid in soil classification and engineering
analysis.
Preparing this report containing a boring location sketch, logs of current and previous soil
borings, a summary of the soils encountered by the current and previous borings, results of
laboratory tests, and recommendations for structure and pavement subgrade preparation
and the design of foundations, floor slabs, exterior slabs, utilities, pavements and stormwater
ponds.
The scope of services for this project included a Phase I Environmental Site Assessment (ESA). The results
of this Phase I ESA are not discussed herein but are provided under separate cover.
B. Results
B.1. Geologic Overview
We based the geologic origins used in this report on the soil types, laboratory testing, and available
common knowledge of the geological history of the site. Because of the complex depositional history,
geologic origins can be difficult to ascertain. We did not perform a detailed investigation of the geologic
history for the site.
B.2. Boring Results
Table 1 provides a summary of the current and previous soil boring results, in the general order they
were encountered. Please refer to the Log of Boring sheets in Appendix A for additional details. The
Descriptive Terminology sheet in Appendix A includes definitions of abbreviations used in Table 1.
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Project B1611559
April 26, 2017
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Table 1. Subsurface Profile Summary*
Strata
Soil Type -
ASTM
Classification
Range of
Penetration
Resistances (BPF) Commentary and Details
Topsoil OL ---
Black.
Thickness at boring SB-4 was 1 foot.
Moisture condition was moist.
Topsoil fill SC, CL ---
Dark brown to black.
Not encountered at boring ST-1
Thicknesses at boring locations varied from 0.5 to
2.5 feet.
Moisture condition generally wet, frozen at time of
drilling.
Engineered
Fill SC, CL 6 to 19
Encountered in northern property.
Thicknesses at boring locations varied from 7 to
18 feet.
Moisture condition generally wet.
Uncontrolled
Fill SC, OL 6 to 9
Encountered in southern property and ST-6.
Thicknesses at boring locations varied from 3 to
7 feet.
Moisture condition varied from moist to
waterbearing.
Glacial
deposits
SC, CL 7 to 32
Encountered in all borings except for ST-7
Consistency of medium to hard.
Variable amounts of gravel; may contain cobbles and
boulders.
General penetration resistance of 10 to 20 BPF.
Moisture condition generally wet.
SP-SM 11 to 23
Encountered at borings SB-1 and SB-2 at depths of 6
and 11 feet below the ground surface and extended
to the boring termination.
Relative density of medium dense
Variable amounts of gravel; may contain cobbles and
boulders.
Moisture condition was waterbearing.
*Abbreviations defined in the attached Descriptive Terminology sheet.
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Project B1611559
April 26, 2017
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B.3. Groundwater
Table 2 summarizes the depths where groundwater was observed; the attached Log of Boring sheets in
Appendix A also include this information and additional details. The table only includes the soil borings
where groundwater was observed.
Table 2. Groundwater Summary
Location
Surface
Elevation
Measured or Estimated
Depth to Groundwater
(ft)
Corresponding
Groundwater Elevation
(ft)
ST-3 911.5 17 894 1/2
ST-5 912.9 9 1/2 903 1/2
ST-6 902.9 2 901
ST-7 907.4 1 1/2 906
SB-1 908 9 899
SB-2 910 5 905
The soil borings encountered groundwater ranging from elevation 894 1/2 to 906 feet MSL with an
average of 900 feet MSL. Seasonal and annual fluctuations of groundwater should be anticipated.
B.4. Laboratory Test Results
The boring logs show the results of the laboratory testing we performed, next to the tested sample
depth. The laboratory tests were all completed in general conformance with the applicable ASTM
standards. The Log of Boring sheets are in Appendix A of this report.
The moisture content tests (ASTM D 2216) we performed showed moisture contents of the clays ranging
from about 9 to 26 percent indicating that the material was generally above its probable optimum
moisture content.
Our mechanical analyses test (ASTM C117) indicated that the clay soil sample from Boring ST-3 that was
tested contained 52 percent silt and clay, by weight. This correlates to a soil classification of sandy lean
clay (CL). DRAFT
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Project B1611559
April 26, 2017
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Our organic content test (ASTM D 2974) indicated that the clay soil sample tested from Boring ST-6
contained 6 percent organic material, by weight. This correlates to a soil type of organic clay (OL).
Our Atterberg Limits test (ASTM D 4318) indicated that the clay soil sample tested from Boring ST-1 had a
liquid limit of 32 percent, a plastic limit of 20 percent and a plasticity index of 12. These results indicate
that the soil is a lean clay (CL) that is not considered expansive.
C. Recommendations
C.1. Design and Construction Discussion
C.1.a. Building Subgrade Preparation
Based on the results of our subsurface exploration and evaluation, spread footing foundations bearing on
engineered fill and/or native soils can support the proposed structures, after performing typical subgrade
preparation. Typical subgrade preparation includes removing existing undocumented fill, topsoil or
organic soils, and structures.
We anticipate cuts and fills to be less than 10 feet from existing grades.
C.1.b. Existing Fill
Based on the results from the Summary Report of Excavation Observations and Compaction Testing,
prepared by Braun Intertec, dated October 6, 2008, the existing non-organic fill on a portion of the
northern property is suitable to support the proposed structures. The exception is the area of Boring
ST-6, where a layer of organic clay fill was encountered below a layer of non-organic clayey sand fill. The
fill and organic clay fill is not directly suitable for structure support and will need to be removed from
beneath future structures and streets. The site grading that occurred in 2008 did not encompass the
entire northern parcel. Soil corrections may be necessary around the existing farmstead and along the
eastern portion of the northern parcel.
The existing fill encountered by the borings in the southern property does not have compaction records
available at this time and should be removed and re-compacted as engineered fill beneath house pads
and oversize areas.
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Project B1611559
April 26, 2017
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C.1.c. Reuse of On-Site Soils
Based on the results of the soil borings, it is our opinion that most of the soils encountered below the
topsoil can be reused as compacted fill, provided that the soils are properly moisture-conditioned. We do
not recommend reusing existing fill that contains debris or organic material as structural fill.
C.1.d. Effects of Groundwater
Within the borings, groundwater was observed at approximate elevations of 898 to 906 feet MSL.
Excavations extending near or below the groundwater levels should be anticipated and require
dewatering. Because most of the soils encountered by the borings consisted of lean clay, sandy lean clay
or clayey sand, controlling water can be completed with sumps and pumps within the excavations.
However, where sand soils are encountered, well points should be anticipated if dewatering is required.
C.2. Site Grading and Subgrade Preparation
C.2.a. Building Subgrade Excavations
We recommend removing unsuitable materials from beneath house pads and oversize areas. We define
unsuitable materials as vegetation, topsoil, undocumented fill, organic soils, existing structures, existing
utilities, and soft/loose soil. Table 3 shows the anticipated excavation depths and approximate bottom of
excavation elevations at each of the boring locations.
Table 3. Building Excavation Depths
Location
Approximate Surface
Elevation (ft)
Anticipated Excavation
Depth (ft)
Anticipated
Bottom Elevation (ft)
ST-1 915.2 0 915
ST-2 914.5 1/2 914
ST-3 911.5 2 1/2 909
ST-4 916.6 1 915 1/2
ST-5 912.9 1 912
ST-6 902.9 7 896
ST-7 907.4 1 906 1/2
SB-1 908 4 904
SB-2 910 6 904
SB-3 907 1 906
SB-4 910 2 908
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Project B1611559
April 26, 2017
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Excavation depths will vary between the borings. Portions of the excavations may also extend deeper
than indicated by the borings. A geotechnical representative should observe the excavations to make the
necessary field judgments regarding the suitability of the exposed soils. Any disturbed areas should be re-
compacted.
The contractor should use equipment and techniques to minimize soil disturbance. If soils become
disturbed or are wet, we recommend excavation and replacement of the disturbed or unstable soils.
C.2.b. Excavation Oversizing
When removing unsuitable materials below structures or pavements, we recommend the excavation
extend outward and downward at a slope of 1H:1V (horizontal:vertical) or flatter. See Figure 1 for an
illustration of excavation oversizing.
Figure 1. Generalized Illustration of Oversizing
1. Engineered fill as defined in C.2
2. Excavation oversizing minimum of 1 to 1
(horizontal to vertical) slope or flatter
3. Engineered fill as required to meet
pavement support or landscaping
requirements as defined in C.2
4. Excavation backslope to OSHA
requirements DRAFT
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Project B1611559
April 26, 2017
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C.2.c. Excavated Slopes
Based on the borings, we anticipate on-site soils in excavations will consist of clay soils. These soils are
typically considered Type B Soil under OSHA (Occupational Safety and Health Administration) guidelines.
OSHA guidelines indicate unsupported excavations in Type B soils should have a gradient no steeper than
1H:1V. Slopes constructed in this manner may still exhibit surface sloughing. OSHA requires an engineer
to evaluate slopes or excavations over 20 feet in depth. The sand soils encountered in Borings SB-1 and
SB-2 consisted of a mixture of sand and clay and are typically considered Type C Soil under OSHA
guidelines. OSHA guidelines indicate unsupported excavations in Type C soils should have a gradient no
steeper than 1.5H:1V.
An OSHA-approved qualified person should review the soil classification in the field. Excavations must
comply with the requirements of OSHA 29 CFR, Part 1926, Subpart P, “Excavations and Trenches.” This
document states excavation safety is the responsibility of the contractor. The project specifications
should reference these OSHA requirements.
C.2.d. Excavation Dewatering
We recommend removing groundwater from the excavations. Project planning should include temporary
sumps and pumps for excavations in low-permeability soils, such as clays. Dewatering of high-
permeability soils (e.g., sands) from within the excavation with conventional pumps has the potential to
loosen the soils, due to upward flow. A well contractor should develop a dewatering plan; the design
team should review this plan.
C.2.e. Selecting Excavation Backfill and Additional Required Fill
On-site soils free of organic soil and debris can be considered for reuse as backfill and fill. However, the
topsoil should not be re-used as engineered fill under house pads or below streets.
C.2.f. Pavement and Exterior Slab Subgrade Preparation
We recommend the following steps for pavement and exterior slab subgrade preparation. Note that
project planning may need to require additional subcuts to limit frost heave.
1. Strip unsuitable soils consisting of topsoil, organic soils, vegetation, existing structures and
pavements from the area, within 3 feet of the surface of the proposed pavement grade.
2. Have a geotechnical representative observe the excavated subgrade to evaluate if additional
subgrade improvements are necessary. DRAFT
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Project B1611559
April 26, 2017
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3. Slope subgrade soils to areas of sand or drain tile to allow the removal of accumulating
water.
4. Scarify, moisture condition and surface compact the subgrade with at least three passes of a
large roller with a minimum drum diameter of 3 1/2 feet.
5. Place pavement fill to grade and compact in accordance with Section C.2.h to bottom of
pavement and exterior slab section.
6. Proofroll the pavement or exterior slab subgrade as described in Section C.2.g.
C.2.g. Pavement Subgrade Proofroll
After preparing the subgrade as described above and prior to the placement of the aggregate base, we
recommend proofrolling the subgrade soils with a fully loaded tandem-axle truck. We also recommend
having a geotechnical representative observe the proofroll. Areas that fail the proofroll likely indicate
soft or weak areas that will require additional soil correction work to support pavements.
The contractor should correct areas that display excessive yielding or rutting during the proofroll, as
determined by the geotechnical representative. Possible options for subgrade correction include
moisture conditioning and re-compaction, subcutting and replacement with soil or crushed aggregate,
chemical stabilization and/or geotextiles. We recommend performing a second proofroll after the
aggregate base material is in place, and prior to placing bituminous or concrete pavement.
C.2.h. Compaction Requirements
We recommend spreading fill in loose lifts of approximately 8 inches thick. We recommend compacting
fill in accordance with the criteria presented below in Table 4. The project documents should specify
relative compaction of fill, based on the structure located above the fill, and vertical proximity to that
structure.
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Project B1611559
April 26, 2017
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Table 4. Compaction Recommendations Summary
Reference
Relative Compaction, percent
(ASTM D698 – Standard Proctor)
Moisture Content Variance from
Optimum, percentage points
Below foundations, less than 10
feet of fill 95 -1 to +3 for clayey soils
±3 for sandy soils
Below foundations, greater than
10 feet of fill 98 -1 to +2 for clayey soils
±3 for sandy soils
Below slabs 95 -1 to +3 for clayey soils
±3 for sandy soils
Below pavements, within 3 feet of
top of subgrade elevations 100 -2 to +1 for clayey soils
±3 for sandy soils
Below pavements, more than 3
feet below subgrade elevations 95 -1 to +3 for clayey soils
±3 for sandy soils
Below landscaped surfaces 90 ±5
The project documents should not allow the contractor to use frozen material as fill or to place fill on
frozen material. Frost should not penetrate under foundations during construction.
We recommend performing density tests in the fill soils to evaluate if the contractors are effectively
compacting the soil and meeting project requirements.
C.3. Spread Footings
C.3.a. Embedment Depth
For frost protection, we recommend embedding perimeter footings of the structures, including attached
garages, a minimum of 42 inches below the lowest exterior grade. Interior footings may be placed
directly below floor slabs provided that the soils below these footings are not allowed to freeze. We
recommend embedding building footings not heated during winter construction, and other unheated
footings associated with decks, porches, stoops or sidewalks 60 inches below the lowest exterior grades.
C.3.b. Subgrade Improvement
If a small amount of groundwater is present within the footing excavation, or if the footing subgrade soils
become disturbed prior to placing forms or reinforcement, we recommend subcutting any soft or wet
soil and placing a 6- to 12-inch layer of clear rock. The clear rock will provide a stable working surface,
and will allow for the flow of water to a drain tile or sump pump. DRAFT
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Project B1611559
April 26, 2017
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C.3.c. Net Allowable Bearing Pressure
We recommend sizing spread footings to exert a net allowable bearing pressure of up to 2,000 pounds
per square foot (psf). This value includes a safety factor of at least 3.0 with regard to bearing capacity
failure. The net allowable bearing pressure can be increased by one-third its value for occasional
transient loads, but not for repetitive loads due to traffic, or for other live loads from snow or occupancy.
C.3.d. Settlement
We estimate that total and differential settlements among the footings will amount to less than 1 and
1/2 inch, respectively, under the assumed loads.
C.4. Interior Slabs
C.4.a. Moisture Vapor Protection
Excess transmission of water vapor could cause floor dampness, certain types of floor bonding agents to
separate, or mold to form under floor coverings. If project planning includes using floor coverings or
coatings, we recommend placing a vapor retarder or vapor barrier immediately beneath the slab. We
also recommend consulting with floor covering manufacturers regarding the appropriate type, use and
installation of the vapor retarder or barrier to preserve warranty assurances.
C.4.b. Radon
In preparation for radon mitigation systems, we recommend that slabs on grade be constructed over a
layer of gas permeable material consisting of a minimum of 4 inches of clean aggregate material and
should consist of rock no larger than 2 inches and no smaller than 1/4 inch. Sand should have less than
50 percent of the particles by weight passing a #40 sieve and less than 5 percent of the particles by
weight passing a #200 sieve. Above the gas permeable aggregate or sand, a polyethylene sheeting (6-mil
minimum) should be placed. The sheeting should be properly lapped and penetrations through the
sheeting sealed. Penetrations through the slab and foundation walls should also be sealed.
C.5. Frost Protection
C.5.a. General
Clay soils will underlie all of the exterior slabs, as well as pavements. We consider these soils to be
moderately to highly frost susceptible. Soils of this type can retain moisture and heave upon freezing. In
general, this characteristic is not an issue unless these soils become saturated, due to surface runoff or
infiltration, or are excessively wet in situ. Once frozen, unfavorable amounts of general and isolated DRAFT
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April 26, 2017
Page 13
heaving of the soils and the surface structures supported on them could develop. This type of heaving
could affect design drainage patterns and the performance of exterior slabs and pavements, as well as
any isolated exterior footings and piers.
Note that general runoff and infiltration from precipitation are not the only sources of water that can
saturate subgrade soils and contribute to frost heave. Roof drainage and irrigation of landscaped areas in
close proximity to exterior slabs, pavements, and isolated footings and piers, contribute as well.
C.5.b. Frost Heave Mitigation
To address most of the heave related issues, we recommend setting general site grades and grades for
exterior surface features to direct surface drainage away from buildings, across large paved areas and
away from walkways. Such grading will limit the potential for saturation of the subgrade and subsequent
heaving. General grades should also have enough “slope” to tolerate potential larger areas of heave,
which may not fully settle after thawing.
Even small amounts of frost-related differential movement at walkway joints or cracks can create
tripping hazards. Project planning can explore several subgrade improvement options to address this
condition.
One of the more conservative subgrade improvement options to mitigate potential heave is removing
any frost-susceptible soils present below the exterior slab areas down to a minimum depth of 5 feet
below subgrade elevations. We recommend filling the resulting excavation with non-frost-susceptible fill.
We also recommend sloping the bottom of the excavation toward one or more collection points to
remove any water entering the engineered fill. This approach will not be effective in controlling frost
heave without removing the water.
An important geometric aspect of the excavation and replacement approach described above is sloping
the banks of the excavations to create a more gradual transition between the unexcavated soils
considered frost susceptible and the engineered fill in the excavated area, which is not frost susceptible.
The slope allows attenuation of differential movement that may occur along the excavation boundary.
We recommend slopes that are 3H:1V, or flatter, along transitions between frost-susceptible and non-
frost-susceptible soils.
Figure 2 shows an illustration summarizing some of the recommendations.
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April 26, 2017
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Figure 2. Frost Protection Geometry Illustration
Another option is to limit frost heave in critical areas, such as doorways and entrances, via frost-depth
footings or localized excavations with sloped transitions between frost-susceptible and non-frost-
susceptible soils, as described above.
Over the life of slabs and pavements, cracks will develop and joints will open up, which will expose the
subgrade and allow water to enter from the surface and either saturate or perch atop the subgrade soils.
This water intrusion increases the potential for frost heave or moisture-related distress near the crack or
joint. Therefore, we recommend implementing a detailed maintenance program to seal and/or fill any
cracks and joints. The maintenance program should give special attention to areas where dissimilar
materials abut one another, where construction joints occur and where shrinkage cracks develop.
C.6. Pavements and Exterior Slabs
C.6.a. Design Sections
Our scope of services for this project did not include laboratory tests on subgrade soils to determine an
R-value for pavement design. Based on our experience with similar clay soils anticipated at the pavement
subgrade elevation, we recommend pavement design assume an R-value of 12. Note the contractor may
need to perform limited removal of unsuitable or less suitable soils to achieve this value.
We assumed that pavements for the residential development would see a maximum of 35,000 ESAL’s
over a 20-year design life. DRAFT
PulteGroup Inc.
Project B1611559
April 26, 2017
Page 15
Based upon the aforementioned traffic loads and an R-value of 12, we recommend a bituminous
pavement section that includes a minimum of 3 1/2 inches of bituminous pavement (a 1 1/2-inch surface
course over a 2-inch base course) over 9 inches of aggregate base material and 12 inches of select
granular fill.
C.6.b. Bituminous Pavement Materials
Appropriate mix designs are critical to the performance of flexible pavements. We can provide
recommendations for pavement material selection during final pavement design.
C.6.c. Subgrade Drainage
We recommend installing perforated drainpipes throughout pavement areas at low points, around catch
basins, and behind curb in landscaped areas. We also recommend installing drainpipes along pavement
and exterior slab edges where exterior grades promote drainage toward those edge areas. The
contractor should place drainpipes in small trenches, extended at least 8 inches below the granular
subbase layer, or below the aggregate base material where no subbase is present.
C.6.d. Performance and Maintenance
We based the above pavement designs on a 20-year performance life for bituminous. This is the amount
of time before we anticipate the pavement will require reconstruction. This performance life assumes
routine maintenance, such as seal coating and crack sealing. The actual pavement life will vary depending
on variations in weather, traffic conditions and maintenance.
It is common to place the non-wear course of bituminous and then delay placement of wear course. For
this situation, we recommend evaluating if the reduced pavement section will have sufficient structure to
support construction traffic.
Many conditions affect the overall performance of the exterior slabs and pavements. Some of these
conditions include the environment, loading conditions and the level of ongoing maintenance. With
regard to bituminous pavements in particular, it is common to have thermal cracking develop within the
first few years of placement, and continue throughout the life of the pavement. We recommend
developing a regular maintenance plan for filling cracks in exterior slabs and pavements to lessen the
potential impacts for cold weather distress due to frost heave or warm weather distress due to wetting
and softening of the subgrade.
DRAFT
PulteGroup Inc.
Project B1611559
April 26, 2017
Page 16
C.7. Utilities
C.7.a. Subgrade Stabilization
Earthwork activities associated with utility installations located inside the building area should adhere to
the recommendations in Section C.2.
For exterior utilities, we anticipate the soils at typical invert elevations will be suitable for utility support.
However, if construction encounters unfavorable conditions such as soft clay, organic soils or perched
water at invert grades, the unsuitable soils may require some additional subcutting and replacement
with sand or crushed rock to prepare a proper subgrade for pipe support. Project design and construction
should not place utilities within the 1H:1V oversizing of foundations.
C.7.b. Selection, Placement, and Compaction of Backfill
We recommend selecting, placing, and compacting utility backfill in accordance with the
recommendations provided above in Section C.2.h.
C.7.c. Dewatering
If excavations to install utilities are anticipated below elevation 905 in the area of SB-1 and SB-2,
dewatering may be required. Due to the sands in this area, dewatering may require the use of well
points.
C.7.d. Corrosion Potential
Based on our experience, the soils encountered by the borings are moderately corrosive to metallic
conduits, but only marginally corrosive to concrete. We recommend specifying non-corrosive materials
or providing corrosion protection, unless project planning chooses to perform additional tests to
demonstrate the soils are not corrosive.
C.8. Stormwater
We estimated infiltration rates for some of the soils we encountered in our soil borings, as listed in
Table 5. These infiltration rates represent the long-term infiltration capacity of a practice and not the
capacity of the soils in their natural state. Field testing, such as with a double-ring infiltrometer (ASTM
D3385), may justify the use of higher infiltration rates. However, we recommend adjusting field test rates
by the appropriate correction factor, as provided for in the Minnesota Stormwater Manual or as allowed
by the local watershed. We recommend consulting the Minnesota Stormwater Manual for stormwater
design.
DRAFT
PulteGroup Inc.
Project B1611559
April 26, 2017
Page 17
Table 5. Estimated Design Infiltration Rates Based on Soil Classification
Soil Type
Infiltration Rate *
(inches/hour)
Clayey sands and clays 0.06
* From Minnesota Stormwater Manual. Rates may differ at individual sites.
Fine-grained soils (silts and clays), topsoil or organic matter that mixes into or washes onto the soil will
lower the permeability. The contractor should maintain and protect infiltration areas during
construction. Furthermore, organic matter and silt washed into the system after construction can fill the
soil pores and reduce permeability over time. Proper maintenance is important for long-term
performance of infiltration systems.
This geotechnical evaluation does not constitute a review of site suitability for stormwater infiltration or
evaluate the potential impacts, if any, from infiltration of large amounts of stormwater.
D. Procedures
D.1. Penetration Test Borings
We drilled the current penetration test borings on February 16, 2017 with a truck-mounted core and
auger drill equipped with hollow-stem auger. We performed the borings in general accordance with
ASTM D6151 taking penetration test samples at 2 1/2- or 5-foot intervals in general accordance to ASTM
D1586. The boring logs show the actual sample intervals and corresponding depths.
D.2. Exploration Logs
D.2.a. Log of Boring Sheets
Appendix A includes Log of Boring sheets for our penetration test borings. The logs identify and describe
the penetrated geologic materials, and present the results of penetration resistance and other laboratory
tests performed.
We inferred strata boundaries from changes in the penetration test samples and the auger cuttings.
Because we did not perform continuous sampling, the strata boundary depths are only approximate. The
boundary depths likely vary away from the boring locations, and the boundaries themselves may occur as
gradual rather than abrupt transitions. DRAFT
PulteGroup Inc.
Project B1611559
April 26, 2017
Page 18
D.2.b. Geologic Origins
We assigned geologic origins to the materials shown on the logs and referenced within this report, based
on: (1) a review of the background information and reference documents cited above, (2) visual
classification of the various geologic material samples retrieved during the course of our subsurface
exploration, (3) penetration resistance and other in-situ testing performed for the project, (4) laboratory
test results, and (5) available common knowledge of the geologic processes and environments that have
impacted the site and surrounding area in the past.
D.3. Material Classification and Testing
D.3.a. Visual and Manual Classification
We visually and manually classified the geologic materials encountered based on ASTM D2488. When we
performed laboratory classification tests, we used the results to classify the geologic materials in
accordance with ASTM D2487. Appendix A includes a chart explaining the classification system we used.
D.3.b. Laboratory Testing
The exploration logs in Appendix A note most of the results of the laboratory tests performed on geologic
material samples. The remaining laboratory test results follow the exploration logs. We performed the
tests in general accordance with ASTM procedures.
D.4. Groundwater Measurements
The drillers checked for groundwater while advancing the penetration test borings, and again after auger
withdrawal. We then filled the boreholes with auger cuttings.
E. Qualifications
E.1. Variations in Subsurface Conditions
E.1.a. Material Strata
We developed our evaluation, analyses and recommendations from a limited amount of site and
subsurface information. It is not standard engineering practice to retrieve material samples from
exploration locations continuously with depth. Therefore, we must infer strata boundaries and DRAFT
PulteGroup Inc.
Project B1611559
April 26, 2017
Page 19
thicknesses to some extent. Strata boundaries may also be gradual transitions, and project planning
should expect the strata to vary in depth, elevation and thickness, away from the exploration locations.
Variations in subsurface conditions present between exploration locations may not be revealed until
performing additional exploration work, or starting construction. If future activity for this project reveals
any such variations, you should notify us so that we may reevaluate our recommendations. Such
variations could increase construction costs, and we recommend including a contingency to
accommodate them.
E.1.b. Groundwater Levels
We made groundwater measurements under the conditions reported herein and shown on the
exploration logs, and interpreted in the text of this report. Note that the observation periods were
relatively short, and project planning can expect groundwater levels to fluctuate in response to rainfall,
flooding, irrigation, seasonal freezing and thawing, surface drainage modifications and other seasonal
and annual factors.
E.2. Continuity of Professional Responsibility
E.2.a. Plan Review
We based this report on a limited amount of information, and we made a number of assumptions to help
us develop our recommendations. We should be retained to review the geotechnical aspects of the
designs and specifications. This review will allow us to evaluate whether we anticipated the design
correctly, if any design changes affect the validity of our recommendations, and if the design and
specifications correctly interpret and implement our recommendations.
E.2.b. Construction Observations and Testing
We recommend retaining us to perform the required observations and testing during construction as
part of the ongoing geotechnical evaluation. This will allow us to correlate the subsurface conditions
exposed during construction with those encountered by the borings and provide professional continuity
from the design phase to the construction phase. If we do not perform observations and testing during
construction, it becomes the responsibility of others to validate the assumption made during the
preparation of this report and to accept the construction-related geotechnical engineer-of-record
responsibilities.
DRAFT
PulteGroup Inc.
Project B1611559
April 26, 2017
Page 20
E.3. Use of Report
This report is for the exclusive use of the addressed parties. Without written approval, we assume no
responsibility to other parties regarding this report. Our evaluation, analyses and recommendations may
not be appropriate for other parties or projects.
E.4. Standard of Care
In performing its services, Braun Intertec used that degree of care and skill ordinarily exercised under
similar circumstances by reputable members of its profession currently practicing in the same locality.
No warranty, express or implied, is made. DRAFT
Appendix A
18
13
12
12
16
14
18
26
LEAN CLAY, with Sand, brown, wet, very stiff to rather
stiff.
(Glacial Till)
SANDY LEAN CLAY, trace Gravel, brown, wet, stiff.
(Glacial Till)
END OF BORING.
Water not observed with 14 1/2 feet of hollow-stem
auger in the ground.
Boring then backfilled.
CL
CL
LL=32, PL=20
PI=12
903.2
899.2
12.0
16.0
LOCATION: See attached sketch.
ST-1
2/16/17 1" = 4'DATE:METHOD:
Description of Materials
(ASTM D2488 or D2487)
ST-1 page 1 of 1
3 1/4" HSA, AutohammerSTS
BORING:
SCALE:DRILLER:
Tests or NotesWL
L O G O F B O R I N G
BPF
(See Descriptive Terminology sheet for explanation of abbreviations)Braun Intertec CorporationB1611559LOG OF BORING-DRAFT N:\GINT\PROJECTS\AX PROJECTS\2016\11559.GPJ BRAUN_V8_CURRENT.GDT 4/26/17 14:51Braun Project B1611559
GEOTECHNICAL EVALUATION
Klingelhutz Property
8601 Great Plains Boulevard
Chanhassen, Minnesota
MC
%
ASTM
Symbol
Elev.
feet
915.2
Depth
feet
0.0
10
16
17
13
20
18
25
19
FILL: Sandy Lean Clay, dark brown, frozen.
(Topsoil Fill)
SANDY LEAN CLAY, trace Gravel, brown, wet, rather
stiff to very stiff.
(Glacial Till)
END OF BORING.
Water not observed with 14 1/2 feet of hollow-stem
auger in the ground.
Boring then backfilled.
FILL
CL
Frozen to 1.8 feet.914.0
898.5
0.5
16.0
LOCATION: See attached sketch.
ST-2
2/16/17 1" = 4'DATE:METHOD:
Description of Materials
(ASTM D2488 or D2487)
ST-2 page 1 of 1
3 1/4" HSA, AutohammerSTS
BORING:
SCALE:DRILLER:
Tests or NotesWL
L O G O F B O R I N G
BPF
(See Descriptive Terminology sheet for explanation of abbreviations)Braun Intertec CorporationB1611559LOG OF BORING-DRAFT N:\GINT\PROJECTS\AX PROJECTS\2016\11559.GPJ BRAUN_V8_CURRENT.GDT 4/26/17 14:51Braun Project B1611559
GEOTECHNICAL EVALUATION
Klingelhutz Property
8601 Great Plains Boulevard
Chanhassen, Minnesota
MC
%
ASTM
Symbol
Elev.
feet
914.5
Depth
feet
0.0
20
14
15
19
24
18
32
52
19
19
FILL: Clayey Sand, black, frozen.
(Topsoil Fill)
SANDY LEAN CLAY, trace Gravel, brown to 18 feet
then gray, wet, stiff to very stiff.
(Glacial Till)
END OF BORING.
Water observed at a depth of 17.3 feet 45 minutes after
drilling.
Boring then backfilled.
FILL
CL
An open triangle in
the water level
(WL) column
indicates the depth
at which
groundwater was
observed while
drilling. A solid
triangle indicates
the groundwater
level in the boring
on the date
indicated.
Groundwater
levels fluctuate.
909.0
890.5
2.5
21.0
LOCATION: See attached sketch.
ST-3
2/16/17 1" = 4'DATE:METHOD:
Description of Materials
(ASTM D2488 or D2487)
ST-3 page 1 of 1
3 1/4" HSA, AutohammerSTS
BORING:
SCALE:DRILLER:
Tests or NotesWL
L O G O F B O R I N G
BPF
(See Descriptive Terminology sheet for explanation of abbreviations)Braun Intertec CorporationB1611559LOG OF BORING-DRAFT N:\GINT\PROJECTS\AX PROJECTS\2016\11559.GPJ BRAUN_V8_CURRENT.GDT 4/26/17 14:51Braun Project B1611559
GEOTECHNICAL EVALUATION
Klingelhutz Property
8601 Great Plains Boulevard
Chanhassen, Minnesota
P200
%
MC
%
ASTM
Symbol
Elev.
feet
911.5
Depth
feet
0.0
13
13
13
15
16
17
18
15
FILL: Lean Clay, dark brown, frozen.
(Topsoil Fill)
FILL: Sandy Lean Clay, trace Gravel, brown, dark
brown and gray, wet.
SANDY LEAN CLAY, trace Gravel, brown, wet, stiff to
very stiff.
(Glacial Till)
END OF BORING.
Water not observed with 14 1/2 feet of hollow-stem
auger in the ground.
Boring then backfilled.
FILL
FILL
CL
Frozen to 1.5 feet.915.9
907.6
900.6
0.7
9.0
16.0
LOCATION: See attached sketch.
ST-4
2/16/17 1" = 4'DATE:METHOD:
Description of Materials
(ASTM D2488 or D2487)
ST-4 page 1 of 1
3 1/4" HSA, AutohammerSTS
BORING:
SCALE:DRILLER:
Tests or NotesWL
L O G O F B O R I N G
BPF
(See Descriptive Terminology sheet for explanation of abbreviations)Braun Intertec CorporationB1611559LOG OF BORING-DRAFT N:\GINT\PROJECTS\AX PROJECTS\2016\11559.GPJ BRAUN_V8_CURRENT.GDT 4/26/17 14:51Braun Project B1611559
GEOTECHNICAL EVALUATION
Klingelhutz Property
8601 Great Plains Boulevard
Chanhassen, Minnesota
MC
%
ASTM
Symbol
Elev.
feet
916.6
Depth
feet
0.0
14
12
12
15
6
12
7
21
17
FILL: Lean Clay, dark brown, frozen.
(Topsoil Fill)
FILL: Sandy Lean Clay, trace Gravel, brown, wet.
FILL: Clayey Sand, trace Gravel, dark brown, wet.
FILL: Sandy Lean Clay, trace Gravel, brown, wet.
FILL: Clayey Sand, trace Gravel, brown, wet.
SANDY LEAN CLAY, trace Gravel, gray, wet, medium.
(Glacial Till)
END OF BORING.
Water observed at 9.6 feet while drilling.
Boring then backfilled.
FILL
FILL
FILL
FILL
FILL
CL
912.2
905.9
903.9
900.9
894.9
891.9
0.7
7.0
9.0
12.0
18.0
21.0
LOCATION: See attached sketch.
ST-5
2/16/17 1" = 4'DATE:METHOD:
Description of Materials
(ASTM D2488 or D2487)
ST-5 page 1 of 1
3 1/4" HSA, AutohammerSTS
BORING:
SCALE:DRILLER:
Tests or NotesWL
L O G O F B O R I N G
BPF
(See Descriptive Terminology sheet for explanation of abbreviations)Braun Intertec CorporationB1611559LOG OF BORING-DRAFT N:\GINT\PROJECTS\AX PROJECTS\2016\11559.GPJ BRAUN_V8_CURRENT.GDT 4/26/17 14:51Braun Project B1611559
GEOTECHNICAL EVALUATION
Klingelhutz Property
8601 Great Plains Boulevard
Chanhassen, Minnesota
MC
%
ASTM
Symbol
Elev.
feet
912.9
Depth
feet
0.0
7
8
11
16
16
15
17
16
38
FILL: Sandy Lean Clay, dark brown, frozen.
(Topsoil Fill)
FILL: Clayey Sand, trace Gravel, brown, wet.
FILL: Organic Clay, black, wet.
SANDY LEAN CLAY, trace Gravel, brown to 12 feet
then gray, wet, rather stiff to very stiff.
(Glacial Till)
END OF BORING.
Water observed at 10.9 feet while drilling.
Water observed at 1.9 feet 2 hours after drilling.
Boring then backfilled.
FILL
FILL
FILL
CL
Frozen to 1 foot.
OC=6%
901.4
898.9
895.9
881.9
1.5
4.0
7.0
21.0
LOCATION: See attached sketch.
ST-6
2/16/17 1" = 4'DATE:METHOD:
Description of Materials
(ASTM D2488 or D2487)
ST-6 page 1 of 1
3 1/4" HSA, AutohammerSTS
BORING:
SCALE:DRILLER:
Tests or NotesWL
L O G O F B O R I N G
BPF
(See Descriptive Terminology sheet for explanation of abbreviations)Braun Intertec CorporationB1611559LOG OF BORING-DRAFT N:\GINT\PROJECTS\AX PROJECTS\2016\11559.GPJ BRAUN_V8_CURRENT.GDT 4/26/17 14:51Braun Project B1611559
GEOTECHNICAL EVALUATION
Klingelhutz Property
8601 Great Plains Boulevard
Chanhassen, Minnesota
MC
%
ASTM
Symbol
Elev.
feet
902.9
Depth
feet
0.0
19
13
8
8
8
18
9
FILL: Sandy Lean Clay, dark brown, frozen.
(Topsoil Fill)
FILL: Clayey Sand, trace Gravel, brown, moist.
FILL: Sandy Lean Clay, trace Gravel, brown and gray,
wet.
CLAYEY SAND, trace Gravel, brown, wet, medium to
very stiff.
(Glacial Till)
END OF BORING.
Water observed at 1.5 feet 30 minutes after drilling.
Boring then backfilled.
FILL
FILL
FILL
SC
Frozen to 1 foot.906.7
903.4
895.4
891.4
0.7
4.0
12.0
16.0
LOCATION: See attached sketch.
ST-7
2/16/17 1" = 4'DATE:METHOD:
Description of Materials
(ASTM D2488 or D2487)
ST-7 page 1 of 1
3 1/4" HSA, AutohammerSTS
BORING:
SCALE:DRILLER:
Tests or NotesWL
L O G O F B O R I N G
BPF
(See Descriptive Terminology sheet for explanation of abbreviations)Braun Intertec CorporationB1611559LOG OF BORING-DRAFT N:\GINT\PROJECTS\AX PROJECTS\2016\11559.GPJ BRAUN_V8_CURRENT.GDT 4/26/17 14:51Braun Project B1611559
GEOTECHNICAL EVALUATION
Klingelhutz Property
8601 Great Plains Boulevard
Chanhassen, Minnesota
MC
%
ASTM
Symbol
Elev.
feet
907.4
Depth
feet
0.0
Rev. 9/15
Descriptive Terminology of Soil
Standard D 2487
Classification of Soils for Engineering Purposes
(Unified Soil Classification System)
a. Based on the material passing the 3-inch (75mm) sieve.
b. If field sample contained cobbles or boulders, or both, add “with cobbles or boulders or both” to group name.
c. Cu = D60/D10 C c = (D30)2
D10 x D60
d. If soil contains ≥15% sand, add “with sand” to group name.
e. Gravels 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
f. If fines classify as CL-ML, use dual symbol GC-GM or SC-SM.
g. If fines are organic, add “with organic fines: to group name.
h. If soil contains ≥15% gravel, add “with gravel” to group name.
i. Sand 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
j. If Atterberg limits plot in hatched area, soil is a CL-ML, silty clay.
k. If soil contains 10 to 29% plus No. 200, add “with sand” or “with gravel” whichever is predominant.
l. If soil contains ≥ 30% plus No. 200, predominantly sand, add “sandy” to group name.
m. If soil contains ≥ 30% plus No. 200, predominantly gravel, add “gravelly” to group name.
n. PI ≥ 4 and plots on or above “A” line.
o. PI < 4 or plots below “A” line.
p. PI plots on or above “A” lines.
q. PI plots below “A” line.
Laboratory Tests
DD Dry density, pcf OC Organic content, %
WD Wet density, pcg S Percent of saturation, %
MC Natural moisture content, % SG Specific gravity
LL Liquid limit, % C Cohesion, psf
PL Plastic limits, % Ø Angle of internal friction
PI Plasticity index, % qu Unconfined compressive strength, psf
P200 % passing 200 sieve qp Pocket penetrometer strength, tsf
Particle Size Identification
Boulders................. over 12”
Cobbles ................. 3” to 12”
Gravel
Coarse ........... 3/4” to 3”
Fine ................ No. 4 to 3/4”
Sand
Coarse ........... No. 4 to No. 10
Medium .......... No. 10 to No. 40
Fine ................ No. 40 to No. 200
Silt ......................... <No. 200, PI< 4 or below
“A” line
Clay ...................... <No. 200, PI > 4 and on
or about “A” line
Relative Density of Cohesionless Soils
Very Loose ............. 0 to 4 BPF
Loose ..................... 5 to 10 BPF
Medium dense ....... 11 to 30 PPF
Dense .................... 31 to 50 BPF
Very dense ............. over 50 BPF
Consistency of Cohesive Soils
Very soft................. 0 to 1 BPF
Soft ........................ 2 to 3 BPF
Rather soft ............. 4 to 5 BPF
Medium .................. 6 to 8 BPF
Rather stiff ............. 9 to 12 BPF
Stiff ........................ 13 to 16 BPF
Very stiff ................. 17 to 30 BPF
Hard ....................... over 30 BPF
Drilling Notes
Standard penetration test borings were advanced by 3 1/4”
or 6 1/4” ID hollow-stem augers, unless noted otherwise.
Jetting water was used to clean out auger prior to sampling
only where indicated on logs. All samples were taken with
the standard 2” OD split-tube samples, except where noted.
Power auger borings were advanced by 4” or 6” diameter
continuous flight, solid-stern augers. Soil classifications and
strata depths were inferred from disturbed samples augered
to the surface, and are therefore, somewhat approximate.
Hand auger borings were advanced manually with a 1 1/2”
or 3 1/4” diameter auger and were limited to the depth from
which the auger could be manually withdrawn.
BPF: Numbers indicate blows per foot recorded in standard
penetration test, also known as “N” value. The sampler was
set 6” into undisturbed soil below the hollow-stem auger.
Driving resistances were then counted for second and third
6” increments, and added to get BPF. Where they differed
significantly, they are reported in the following form: 2/12 for
the second and third 6” increments, respectively.
WH: WH indicates the sampler penetrated soil under weight
of hammer and rods alone; driving not required.
WR: WR indicates the sampler penetrated soil under weight
of rods alone; hammer weight, and driving not required.
TW: TW indicates thin-walled (undisturbed) tube sample.
Note: All tests were run in general accordance with
applicable ASTM standards.
ML or OL
Appendix B