8.0 Galpin Geotechnical Evaluation - Nelson Properties B1805858
Table of Contents
Description Page
A. Introduction ...................................................................................................................................... 1
A.1. Project Description .............................................................................................................. 1
A.1.a. Structural Loads ...................................................................................................... 1
A.1.b. Pavement Traffic Loads .......................................................................................... 1
A.2. Site Conditions and History ................................................................................................. 1
A.3. Purpose ................................................................................................................................ 2
A.4. Background Information and Reference Documents .......................................................... 2
A.5. Scope of Services ................................................................................................................. 3
B. Results .............................................................................................................................................. 4
B.1. Geologic Overview .............................................................................................................. 4
B.2. Boring Results ...................................................................................................................... 4
B.3. Groundwater ....................................................................................................................... 5
B.4. Laboratory Test Results ....................................................................................................... 5
C. Recommendations ........................................................................................................................... 5
C.1. Design and Construction Discussion ................................................................................... 5
C.1.a. Building Subgrade Preparation .............................................................................. 5
C.1.b. Reuse of On-Site Soils ............................................................................................. 6
C.1.c. Disturbance of On-Site Soils ................................................................................... 6
C.1.d. Effects of Groundwater .......................................................................................... 6
C.2. Site Grading and Subgrade Preparation .............................................................................. 6
C.2.a. Building Subgrade Excavations ............................................................................... 6
C.2.b. Excavation Oversizing ............................................................................................. 7
C.2.c. Excavated Slopes .................................................................................................... 8
C.2.d. Filling on Slopes ...................................................................................................... 9
C.2.e. Excavation Dewatering ........................................................................................... 9
C.2.f. Selecting Excavation Backfill and Additional Required Fill ..................................... 9
C.2.g. Pavement and Exterior Slab Subgrade Preparation ............................................. 10
C.2.h. Pavement Subgrade Proofroll .............................................................................. 10
C.2.i. Engineered Fill Materials and Compaction Requirements ................................... 10
C.3. Spread Footings ................................................................................................................. 12
C.3.a. Embedment Depth ............................................................................................... 12
C.3.b. Subgrade Improvement ....................................................................................... 12
C.3.c. Net Allowable Bearing Pressure ........................................................................... 13
C.3.d. Settlement ............................................................................................................ 13
C.4. Below-Grade Walls ............................................................................................................ 13
C.4.a. Drainage Control .................................................................................................. 13
C.4.b. Selection, Placement and Compaction of Backfill ................................................ 15
C.4.c. Configuring and Resisting Lateral Loads............................................................... 16
C.5. Interior Slabs ..................................................................................................................... 17
C.5.a. Moisture Vapor Protection .................................................................................. 17
C.5.b. Radon ................................................................................................................... 17
C.6. Frost Protection ................................................................................................................. 17
C.6.a. General ................................................................................................................. 17
C.6.b. Frost Heave Mitigation ......................................................................................... 18
Table of Contents (continued)
Description Page
C.7. Pavements and Exterior Slabs ........................................................................................... 19
C.7.a. Design Sections .................................................................................................... 19
C.7.b. Bituminous Pavement Materials .......................................................................... 20
C.7.c. Subgrade Drainage ............................................................................................... 20
C.7.d. Performance and Maintenance ........................................................................... 20
C.8. Utilities .............................................................................................................................. 21
C.8.a. Subgrade Stabilization .......................................................................................... 21
C.8.b. Selection, Placement, and Compaction of Backfill ............................................... 21
C.8.c. Corrosion Potential .............................................................................................. 21
D. Procedures...................................................................................................................................... 21
D.1. Penetration Test Borings ................................................................................................... 21
D.2. Exploration Logs ................................................................................................................ 22
D.2.a. Log of Boring Sheets ............................................................................................. 22
D.2.b. Geologic Origins ................................................................................................... 22
D.3. Material Classification and Testing ................................................................................... 22
D.3.a. Visual and Manual Classification .......................................................................... 22
D.3.b. Laboratory Testing ............................................................................................... 22
D.4. Groundwater Measurements ............................................................................................ 23
E. Qualifications .................................................................................................................................. 23
E.1. Variations in Subsurface Conditions .................................................................................. 23
E.1.a. Material Strata ..................................................................................................... 23
E.1.b. Groundwater Levels ............................................................................................. 23
E.2. Continuity of Professional Responsibility .......................................................................... 24
E.2.a. Plan Review .......................................................................................................... 24
E.2.b. Construction Observations and Testing ............................................................... 24
E.3. Use of Report..................................................................................................................... 24
E.4. Standard of Care ................................................................................................................ 24
Appendix
Soil Boring Location Sketch
Log of Boring Sheets ST-1 through ST-8
Descriptive Terminology of Soil
A. Introduction
A.1. Project Description
Lennar Corporation is planning to develop a single-family housing development on the Nelson Properties
along the east side of Galpin Boulevard in Chanhassen, Minnesota. This site is comprised of 5 separate
but adjoining parcels of land totaling about 188 acres. However, a substantial part of this site is
considered to be wetlands. The proposed development will consist of approximately 200 single-family
house sites. The development will also include the construction of the associated streets, underground
utilities, and stormwater features/ponds.
A.1.a. Structural Loads
We understand the construction will consist of 1- to 2-story wood-framed houses with pitched roofs and
full basements on poured concrete foundations. Based on the residential construction, we have based
our analysis and recommendations on the assumption that footing pressures will not exceed 2,000 psf.
Please contact us if this information is not correct.
A.1.b. Pavement Traffic Loads
We have assumed that bituminous pavements, typical of residential neighborhoods, will be subjected to
normal traffic conditions over a design life of 20 years.
A.2. Site Conditions and History
The site is located on the east side of Galpin Boulevard and north of 30th Street NE. The ground surface
consists of rolling terrain with current grades, based on the elevations at the soil borings, ranging from
about elevation 960 feet to 1020 feet Mean Sea Level (MSL). There are several wetlands on this site,
including some open water. There are also some wooded areas on this site.
The following recent aerial photograph shows the current site conditions, as obtained through Google
Earth.
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Photograph 1. Aerial Photograph of the Site
Photograph provided by Google Earth®
A.3. Purpose
The purpose of our geotechnical evaluation will be to characterize subsurface geologic conditions at
selected exploration locations and evaluate their impact on the design and construction of the residential
development.
A.4. Background Information and Reference Documents
We reviewed the following information:
Available public aerial photographs showing the existing site conditions.
Undated Preliminary Site Concept plans prepared by Pioneer Engineering.
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Carver County property maps showing the different parcels of property and potential
wetlands.
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 completed our services based on the Proposal for Geotechnical Evaluation to Mr. Ben Bahr of Lennar
Corporation. 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. The
boring locations were chosen and staked in the field by Pioneer Engineering. The existing
ground surface elevations at the borings were also provided by Otto.
Performing 8 standard penetration test (SPT) borings, denoted as ST-1 to ST-8, to nominal
depths of 14 1/2 feet below grade across the site.
Performing laboratory testing on select samples to aid in soil classification and engineering
analysis.
Preparing this report containing a boring location sketch, logs of the soil borings, a summary
of the soils encountered by the current borings, results of laboratory tests, and
recommendations for structure and pavement subgrade preparation and the design of
foundations, floor slabs, exterior slabs and utilities.
When the borings were being completed, Boring ST-6 encountered some marginal soil at the planned
termination depth of 14 1/2 feet. This boring was subsequently extended an additional 5 feet.
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Our scope of services did not include environmental services or testing, and we did not train the
personnel performing this evaluation to provide environmental services or testing. We can provide these
services or testing at your request.
B. Results
B.1. Geologic Overview
We based the geologic origins used in this report on the soil types, in-situ and 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 soil boring results in the general order we encountered the
strata. Please refer to the Log of Boring sheets in the Appendix for additional details. The Descriptive
Terminology sheet in the Appendix includes definitions of abbreviations used in Table 1.
Table 1. Subsurface Profile Summary*
Strata
Soil Type -
ASTM
Classification
Range of
Penetration
Resistances Commentary and Details
Fill Soils OL, CL
Encountered by Borings ST-1, ST-3 and ST-6.
Mostly organic clay with some lean clay and sandy
lean clay.
Ranged in thickness from about 2 to 9 feet.
Moisture condition generally moist.
Topsoil OL
Consisted of black organic clay.
Thickness ranged from 1/2 to 2 1/2 feet.
Moisture condition generally moist.
Glacial
deposits CL, SC 2 to 17 BPF
Mostly sandy lean clay, lean clay or clayey sand.
Variable amounts of gravel and cobbles.
Moisture condition generally moist.
*Abbreviations defined in the attached Descriptive Terminology sheet.
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B.3. Groundwater
While drilling the borings, groundwater was only observed in Boring ST-6 at a depth of about 6 feet, or an
elevation of about 885 MSL. However, based on the recovered soil samples, it is likely that the water
observed was perched in lenses of silty sand.
The attached Log of Boring sheets in the Appendix also include water level information and additional
details. 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 the Appendix of this report.
The moisture content tests (ASTM D 2216) performed on selected soil samples showed moisture
contents ranging from about 16 to 32 percent. The majority of the soils tested appeared to be near or
slightly above the soils estimated optimum moisture content.
Pocket penetrometer tests were completed on selected clayey soil samples to estimate the unconfined
compressive strength of the soils. The results ranged from about 1/4 to 2 tons per square foot (tsf).
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 houses after performing typical subgrade
preparation. Typical subgrade preparation includes removing existing vegetation, topsoil or organic soils,
swamp deposits, fill soils, and any existing structures, along with areas of soft clays.
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We estimate that cuts and fills could range from about 5 to 15 feet from existing grades. Any soil
correction work to further remove unsuitably soft soils could add or subtract to these assumed cut and
fill depths.
C.1.b. Reuse of On-Site Soils
The on-site fill soils, free of organic materials and debris, as well as most of the native soils appear
suitable for reuse as engineered fill. Some of the soil samples appeared to be overly wet and will likely
require drying to allow the recommended soil compaction levels to be achieved. We caution that some
of the lean clays encountered on the site are very wet and will be extremely moisture sensitive and likely
be difficult for reuse and compaction. Additional moisture conditioning will likely be required prior to
reuse for structural fill. Any materials to be used as engineered fill should be tested and approved by the
geotechnical engineer prior to placement.
C.1.c. Disturbance of On-Site Soils
We caution that the clayey nature of some of the site soils makes them susceptible to disturbance from
construction. Care should be taken not to disturb these soils during construction, as once stable
subgrades can be destabilized and require additional moisture conditioning and compacting.
C.1.d. Effects of Groundwater
Groundwater is anticipated to be below typical excavation depths at this site, although perched water
could be present at higher elevations within layers of granular soils overlying lower permeability soils.
The contractor should immediately remove any collected water within the excavations to facilitate
construction and proper backfilling.
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, swamp deposits, fill, organic soils, existing structures, existing
utilities, and soft/loose soil. Table 2 shows the anticipated excavation depths and bottom of soil
correction excavation elevations at each of the current soil boring locations, assuming that structures,
utilities or roads will be built at each location. Excavation depths could be reduced in areas that will not
support future structures, utilities or roads.
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Table 2. Recommended Excavation Depths for Building Pads
Location
Approximate Surface
Elevation
(ft)
Anticipated Excavation
Depth
(ft)
Anticipated
Bottom Elevation
(ft)
ST-1 980.8 5 975 1/2
ST-2 1002.9 1/2-5 1002 1/2-998*
ST-3 970.1 4 966
ST-4 963.4 1-4* 962-959*
ST-5 980.8 2 1/2 978
ST-6 991.4 9-18* 982-973*
ST-7 1018.2 1 1017
ST-8 1001.3 1 1/2-9* 1000 1/2-992*
*To be determined in the field during site grading activities.
Due to variability in soil conditions and the presence of wetland areas, at some of the soil boring
locations we have given a range of expected soil correction excavation depths. 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 reduce soil disturbance. If soils become
disturbed or are wet, we recommend excavation and replacement of the disturbed or unstable soils.
Provided the existing soils do not become disturbed, surface compaction will not be necessary prior to
construction of footings.
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.
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Figure 1. Generalized Illustration of Oversizing
C.2.c. Excavated Slopes
Based on the borings, we anticipate on-site soils in excavations will consist of mostly clayey soils with
lesser amounts of sandy soils. The clay 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 1:1V. The sand soils are typically
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. Slopes constructed in this manner may still exhibit
surface sloughing. OSHA requires an engineer to evaluate slopes or excavations over 20 feet in depth.
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.
1. Engineered fill as defined in C.2.i
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.i
4. Excavation back-slope to OSHA requirements
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C.2.d. Filling on Slopes
Where existing or excavated grades are steeper than 4H:1V, we recommend placing fill from low to high
elevations on horizontal benches cut into the native soils so that successive lifts are spread and
compacted on level surfaces, and a potential failure surface is not created along the fill’s lower boundary.
Depending on fill requirements, the contractor can construct benches by cutting into existing grades
while placing fill (the composition of the exposed soils thus being in compliance with fill specifications),
or by cutting the benches in advance of filling (to prevent mixing with soils not in compliance with fill
specifications). The height of a given bench may vary but the width should consistently be great enough
to accommodate large, self-propelled compaction equipment.
C.2.e. 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.f. 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 and the organic fill soils should not be re-used as engineered fill under house pads or below
streets. Although clays can be used as fill if properly moisture conditioned and compacted, for ease of
construction, if possible, the higher moisture content clay should not be used as engineered fill below
house pads and streets.
Unless a drainage composite is placed against the backs of the exterior perimeter basement walls, we
recommend that backfill placed within 2 horizontal feet of those walls consist of sand having 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. Sand meeting this gradation will need to imported to the site. We
recommend that the balance of the backfill placed against exterior perimeter walls also consist of sand;
although it is our opinion that the sand may contain up to 20 percent of the particles, by weight, passing
a #200 sieve.
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C.2.g. 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. Silt soils, if within the frost
zone, can lead to a very high risk of damaging 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.
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 3 passes by 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.i to bottom of
pavement and exterior slab section.
6. Proofroll the pavement or exterior slab subgrade as described in Section C.2.h.
C.2.h. 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 or slabs.
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/slabs.
C.2.i. Engineered Fill Materials and Compaction Requirements
Table 3 below contains our recommendations for engineered fill materials.
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Table 3. Engineered Fill Materials
Locations To Be Used
Engineered Fill
Classification
Possible Soil Type
Descriptions Gradation
Additional
Requirements
Below foundations
Below interior slabs Structural fill SP, SP-SM, SM,
SC, CL 100% passing 2-inch sieve
< 2% Organic
Content (OC)
Plasticity Index (PI)
< 15%
Drainage layer
Non-frost-
susceptible
Free-draining
Non-frost-
susceptible fill
GP, GW, SP, SW
100% passing 1-inch sieve
< 50% passing #40 sieve
< 5% passing #200 sieve
< 2% OC
Behind below-grade
walls, beyond
drainage layer
Retained fill SP, SW, SP-SM,
SW-SM, SM
100% passing 3-inch sieve
< 20% passing #200 sieve
< 2% OC
PI< 4%
Pavements Pavement fill SP, SP-SM, SM,
SC, CL 100% passing 3-inch sieve < 2% OC
PI < 15%
Below landscaped
surfaces, where
subsidence is not a
concern
Non-structural fill 100% passing 6-inch sieve < 10% OC
* More select soils comprised of coarse sands with < 5% passing #200 sieve may be needed to accommodate work occurring in
periods of wet or freezing weather.
Based on the rolling terrain and the need for some deeper soil correction work, it is likely that some of
the house pads will require more than 10 feet of compacted fill. If only clay fill is used to fill those house
pads where more than 10 feet of fill is needed, a construction delay ranging from 3 to 12 months may be
needed, depending on the final depths of clay fill used. As an alternative, on lots where deep fills are
needed, clean sand fill (less than 12 percent passing the number 200 sieve) could be used to initially fill
the excavations below these house pads. The clean sand fill should be placed in thin compacted lifts up
to an elevation of 10 feet of less from finished basement floor grades. On-site clay fill can then be used to
complete construction of the building pads. If the alternative method of filling the house pads is used, a
construction delay would not be needed.
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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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 clay soils
±3 for sandy soils
Below foundations, greater th an
10 feet of fill 98 -1 to +2 for clay soils
±3 for sandy soils
Below slabs 95 -1 to +3 for clay soils
±3 for sandy soils
Below pavements, within 3 feet of
top of subgrade elevations 100 -2 to +1 for clay soils
±3 for sandy soils
Below pavements, more than
3 feet below subgrade elevations 95 -1 to +3 for clay soils
±3 for sandy soils
Below landscaped surfaces 90 -1 to +5 for clay soils
±6 for sandy soils
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 fill to evaluate if the contractors are effectively compacting
the soil and meeting project requirements.
Refer to Section C.3.d below for additional remarks for thicker layers of fill soils.
C.3. Spread Footings
C.3.a. Embedment Depth
For frost protection, we recommend embedding perimeter footings of the proposed houses, including
attached garages, a minimum of 42 inches below the lowest exterior grade. Interior footings may be
placed directly below floor slabs unless they will be subjected to freezing. 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 grade.
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.
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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.
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. If there are areas where more than 10 feet of fill is
required, higher settlements could occur, unless the deeper fill areas are only filled with poorly graded
sand (SP) or poorly graded sand with silt (SP-SM) fill.
If deep fill areas are completed using clay soil, a construction delay may also be needed to allow the fill
soils to consolidate under its own weight. Construction delays could range from 6 to 12 months,
depending on the type of fill used, the compaction level obtained in the fill and the thickness of the fill.
The construction delays should be evaluated after grading is completed by using settlement plates to
monitor the consolidation of the fill.
C.4. Below-Grade Walls
The following sections address soil parameters for basement wall design. Although construction of
retaining walls has not been specified for this project to date, the following recommendations can also
be used for preliminary retaining wall design. We recommend that additional soil borings be completed
for final retaining wall design.
C.4.a. Drainage Control
We recommend installing drain tile to remove water behind the below-grade walls at the location shown
in Figure 2. The below-grade wall drainage system should also incorporate free-draining, engineered fill
or a drainage board placed against the wall and connected to the drain tile.
Even with the use of free-draining, engineered fill, we recommend general waterproofing of below-grade
walls that surround occupied or potentially occupied areas because of the potential cost impacts related
to seepage after construction is complete.
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Figure 2. Generalized Illustration of Wall Engineered Fill
The materials listed in the sketch should meet the definitions in Section C.4.b. Low-permeability material
is capable of directing water away from the wall, like clay, topsoil or pavement. The project documents
should indicate if the contractor should brace the walls prior to filling, and the allowable unbalanced fill
heights.
As shown in Figure 2, we recommend Zone 2 consist of retained, engineered fill, and this material will
control lateral pressures on the wall. However, we are also providing design parameters for using other
engineered fill material. If final design uses non-sand material for engineered fill, project planning should
account for the following items:
Other engineered fill material may result in higher lateral pressure on the wall.
Other engineered fill material may be more difficult to compact.
1. 2-foot wide area of Free-
Draining Engineered Fill or
Drainage Board
2. Retained Engineered Fill
3. 1 foot of Low-Permeability
Soil or Pavement
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Post-construction consolidation of other engineered fill material may result in settlement-
related damage to the structures or slabs supported on the engineered fill. Post-construction
settlement of other engineered fill material may also cause drainage towards the structure.
The magnitude of consolidation could be up to about 3 percent of the wall fill thickness.
C.4.b. Selection, Placement and Compaction of Backfill
Unless a drainage composite is placed against the backs of the exterior perimeter basement walls, we
recommend that backfill placed within 2 horizontal feet of those walls consist of sand having 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. Sand meeting this gradation will likely need to imported to the site. We
recommend that the balance of the backfill placed against exterior perimeter walls also consist of sand,
though it is our opinion that the sand may contain up to 20 percent of the particles, by weight, passing a
#200 sieve.
If clay must be considered for use to make up the balance of the below-grade wall backfill (assuming a
drainage composite or sand is placed against the backs of the walls), post-compaction consolidation of
the clay occurring under its own weight can be expected to continue beyond the end of construction. The
magnitude of consolidation could amount to between 1 and 3 percent of the backfill thickness, or wall
height, and if not accommodated, could cause slabs or pavements to settle unfavorably or be damaged.
Should clay still be considered for use as backfill, however, we further recommend that:
The bottoms of the excavations required for basement wall construction are wide enough to
accommodate compaction equipment.
Backfill is placed at moisture contents at least equal to, but not more than, 3 percentage
points above its optimum moisture content.
Backfill is placed in loose lifts no thicker than 6 inches prior to compaction.
The relative compaction of the backfill is measured through density testing at intervals not
exceeding 1 test per 50 horizontal feet for each 2 vertical feet of backfill placed.
We recommend using a walk-behind compactor to compact the backfill placed within about 5 feet of the
basement walls. Further away than that, a self-propelled compactor can be used. Compaction criteria for
basement walls should be determined based on the compaction recommendations provided above in
Section C.2.
Lennar Corporation
Project B1805858
June 29, 2018
Page 16
Exterior backfill not capped with slabs or pavement should be capped with a low-permeability soil to limit
the infiltration of surface drainage into the backfill. The finished surface should also be sloped to divert
water away from the walls.
C.4.c. Configuring and Resisting Lateral Loads
Below-grade wall design can use active earth pressure conditions, if the walls can rotate slightly. If the
wall design cannot tolerate rotation, then design should use at-rest earth pressure conditions. Rotation
up to 0.002 times the wall height is generally required for walls supporting sand. Rotation up to 0.02
times the wall height is required when wall supports clay.
Table 5 presents our recommended lateral coefficients and equivalent fluid pressures for wall design of
active, at-rest and passive earth pressure conditions. The table also provides recommended wet unit
weights and internal friction angles. Designs should also consider the slope of any engineered fill and
dead or live loads placed behind the walls within a horizontal distance that is equal to the height of the
walls. Our recommended values assume the wall design provides drainage so water cannot accumulate
behind the walls. The construction documents should clearly identify what soils the contractor should
use for engineered fill of walls.
Table 5. Recommended Below-Grade Wall Design Parameters – Drained Conditions
Retained Soil
Wet Unit
Weight,
pcf
Friction
Angle,
(degrees
Equivalent Active
Fluid Pressure*
(pcf)
Equivalent At-Rest
Fluid Pressure*
(pcf)
Equivalent Passive
Fluid Pressure*
(pcf)
Sand (SP, SP-SM) 120 33 35 55 400
Silty Sand (SM) 125 30 42 62 360
Clay (CL) 120 26 47 70 300
* Based on Rankine model for soils in a region behind the wall extending at least 2 horizontal feet beyond the bottom outer
edges of the wall footings and then rising up and away from the wall at an angle no steeper than 60 degrees from horizontal.
Sliding resistance between the bottom of the footing and the soil can also resist lateral pressures. We
recommend assuming a sliding coefficient equal to 0.30 between the concrete and clay soil.
The values presented in this section are un-factored.
Lennar Corporation
Project B1805858
June 29, 2018
Page 17
C.5. Interior Slabs
C.5.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.5.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 either clean aggregate material or
coarse sand. The aggregate material 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.6. Frost Protection
C.6.a. General
A mixture of clay and silty sand soil will likely underlie all of the exterior slabs, as well as pavements.
Most of these soils are considered to be moderately to highly frost susceptible. The fine-grained soils as
well as some of the silty sand 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 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.
Lennar Corporation
Project B1805858
June 29, 2018
Page 18
C.6.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 4 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.
Lennar Corporation
Project B1805858
June 29, 2018
Page 19
Figure 3 that follows shows an illustration summarizing some of the recommendations.
Figure 3. 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.7. Pavements and Exterior Slabs
C.7.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. Since most of the soils on this site consist of clay, we recommend that the
pavements be designed for an assume R-value of 10. Note the contractor may need to perform limited
removal of unsuitable or less suitable soils to achieve this value.
Lennar Corporation
Project B1805858
June 29, 2018
Page 20
We assumed that pavements for the residential development will be subject to a maximum of 50,000
ESALs over a 20-year design life.
Based upon the aforementioned traffic loads and an R-value of 10, we recommend a bituminous
pavement section for the local residential streets 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 8 inches of aggregate base
material, and 12 inches of select granular fill. The City of Chanhassen may have a standard pavement
section that is different.
C.7.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.7.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.7.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 the 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
Lennar Corporation
Project B1805858
June 29, 2018
Page 21
potential impacts for cold weather distress due to frost heave or warm weather distress due to wetting
and softening of the subgrade.
C.8. Utilities
C.8.a. Subgrade Stabilization
Earthwork activities associated with utility installations located inside building pad areas 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.8.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.i.
C.8.c. Corrosion Potential
Based on our experience, some of the clay soils encountered by the borings are moderately corrosive to
metallic conduits. However, the sand soils are generally not corrosive to metallic conduits. If the pipe
may be embedded in clay soils, 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.
D. Procedures
D.1. Penetration Test Borings
We drilled the penetration test borings on June 21, 2018, with an off-road-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.
Lennar Corporation
Project B1805858
June 29, 2018
Page 22
D.2. Exploration Logs
D.2.a. Log of Boring Sheets
The Appendix 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
in-situ tests performed. The logs also present the results of laboratory tests performed on penetration
test samples, and groundwater measurements.
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.
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. The Appendix includes a chart explaining the classification system we
used.
D.3.b. Laboratory Testing
The exploration logs in the Appendix note the results of the laboratory tests performed on geologic
material samples. We performed the tests in general accordance with ASTM procedures.
Lennar Corporation
Project B1805858
June 29, 2018
Page 23
D.4. Groundwater Measurements
The drillers checked for groundwater while advancing the penetration test borings, and again after auger
withdrawal. We then immediately filled the boreholes.
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
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.
Lennar Corporation
Project B1805858
June 29, 2018
Page 24
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. Braun Intertec 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. Braun Intertec should also be
retained to complete the soil observations and testing as the site is being graded.
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.
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.
Appendix
4
5
7
8
6
8
1 1/2
Benchmark: Soil
boring elevations
provided by
Pioneer
Engineering.28
25
FILL
FILL
CL
CL
FILL: Organic Clay, black, moist.
FILL: Sandy Lean Clay, trace Gravel, light and dark
brown, moist.
SANDY LEAN CLAY, trace Gravel, brown, moist,
medium.
(Glacial Till)
SANDY LEAN CLAY, trace Gravel, gray, moist, medium.
(Glacial Till)
END OF BORING.
Water not observed while drilling.
Boring immediately backfilled.
978.3
976.8
973.8
966.3
2.5
4.0
7.0
14.5
6/21/18 1" = 4'DATE:SCALE:DRILLER:
Tests or NotesWL
ST-1 page 1 of 1
3 1/4" HSA, AutohammerM. Takada
L O G O F B O R I N G
(See Descriptive Terminology sheet for explanation of abbreviations)LOCATION: See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-1
METHOD:
BORING:
BPF
Braun Intertec CorporationB1805858LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2018\05858.GPJ BRAUN_V8_CURRENT.GDT 6/29/18 09:21Braun Project B1805858
GEOTECHNICAL EVALUATION
Nelson Properties
7141 Galpin Boulevard
Chanhassen, Minnesota
qp
tsf
MC
%Symbol
Elev.
feet
980.8
Depth
feet
0.0
4
12
11
12
13
13
3/432
30
OL
CL
CL
ORGANIC CLAY, dark brown, moist.
(Topsoil)
LEAN CLAY with SAND, trace Gravel, brown, moist, soft
to stiff.
(Glacial Till)
SANDY LEAN CLAY, trace Gravel, brown, moist, stiff.
(Glacial Till)
With seams of Silty Sand from 10 to 14 feet.
END OF BORING.
Water not observed while drilling.
Boring immediately backfilled.
1002.4
993.9
988.4
0.5
9.0
14.5
6/21/18 1" = 4'DATE:SCALE:DRILLER:
Tests or NotesWL
ST-2 page 1 of 1
3 1/4" HSA, AutohammerM. Takada
L O G O F B O R I N G
(See Descriptive Terminology sheet for explanation of abbreviations)LOCATION: See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-2
METHOD:
BORING:
BPF
Braun Intertec CorporationB1805858LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2018\05858.GPJ BRAUN_V8_CURRENT.GDT 6/29/18 09:21Braun Project B1805858
GEOTECHNICAL EVALUATION
Nelson Properties
7141 Galpin Boulevard
Chanhassen, Minnesota
qp
tsf
MC
%Symbol
Elev.
feet
1002.9
Depth
feet
0.0
5
13
6
12
10
10
1 1/4
16
19
FILL
OL
SC
CL
CL
FILL: Lean Clay, trace organics, brown and black, moist.
ORGANIC CLAY, black, moist.
(Topsoil)
CLAYEY SAND, trace Gravel, brown, moist, stiff.
(Glacial Till)
SANDY LEAN CLAY, seams of Silty Sand, trace Gravel,
light grayish brown, moist, medium.
(Glacial Till)
SANDY LEAN CLAY, trace Gravel, brown, moist, stiff.
(Glacial Till)
END OF BORING.
Water not observed while drilling.
Boring immediately backfilled.
968.3
966.1
963.1
960.1
955.6
1.8
4.0
7.0
10.0
14.5
6/21/18 1" = 4'DATE:SCALE:DRILLER:
Tests or NotesWL
ST-3 page 1 of 1
3 1/4" HSA, AutohammerM. Takada
L O G O F B O R I N G
(See Descriptive Terminology sheet for explanation of abbreviations)LOCATION: See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-3
METHOD:
BORING:
BPF
Braun Intertec CorporationB1805858LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2018\05858.GPJ BRAUN_V8_CURRENT.GDT 6/29/18 09:21Braun Project B1805858
GEOTECHNICAL EVALUATION
Nelson Properties
7141 Galpin Boulevard
Chanhassen, Minnesota
qp
tsf
MC
%Symbol
Elev.
feet
970.1
Depth
feet
0.0
5
8
7
12
11
11
3/4
2
20
19
OL
CL
CL
CL
ORGANIC CLAY, black, moist.
(Topsoil)
SANDY LEAN CLAY, trace Gravel, seams of Silty Sand,
grayish brown, moist, medium.
(Glacial Till)
SANDY LEAN CLAY, trace Gravel, brown, moist,
medium.
(Glacial Till)
SANDY LEAN CLAY, trace Gravel, gray, moist, stiff.
(Glacial Till)
END OF BORING.
Water not observed while drilling.
Boring immediately backfilled.
962.4
959.4
954.4
948.9
1.0
4.0
9.0
14.5
6/21/18 1" = 4'DATE:SCALE:DRILLER:
Tests or NotesWL
ST-4 page 1 of 1
3 1/4" HSA, AutohammerM. Takada
L O G O F B O R I N G
(See Descriptive Terminology sheet for explanation of abbreviations)LOCATION: See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-4
METHOD:
BORING:
BPF
Braun Intertec CorporationB1805858LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2018\05858.GPJ BRAUN_V8_CURRENT.GDT 6/29/18 09:21Braun Project B1805858
GEOTECHNICAL EVALUATION
Nelson Properties
7141 Galpin Boulevard
Chanhassen, Minnesota
qp
tsf
MC
%Symbol
Elev.
feet
963.4
Depth
feet
0.0
6
10
10
16
13
12
1 1/228
19
OL
CL
CL
CL
ORGANIC CLAY, black, moist.
(Topsoil)
LEAN CLAY, grayish brown, moist, medium.
(Glacial Till)
SANDY LEAN CLAY, trace Gravel, brown, moist, stiff to
very stiff.
(Glacial Till)
With seams of Silty Sand at 10 feet.
SANDY LEAN CLAY, trace Gravel, gray, moist, stiff.
(Glacial Till)
END OF BORING.
Water not observed while drilling.
Boring immediately backfilled.
978.3
976.8
968.8
966.3
2.5
4.0
12.0
14.5
6/21/18 1" = 4'DATE:SCALE:DRILLER:
Tests or NotesWL
ST-5 page 1 of 1
3 1/4" HSA, AutohammerM. Takada
L O G O F B O R I N G
(See Descriptive Terminology sheet for explanation of abbreviations)LOCATION: See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-5
METHOD:
BORING:
BPF
Braun Intertec CorporationB1805858LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2018\05858.GPJ BRAUN_V8_CURRENT.GDT 6/29/18 09:21Braun Project B1805858
GEOTECHNICAL EVALUATION
Nelson Properties
7141 Galpin Boulevard
Chanhassen, Minnesota
qp
tsf
MC
%Symbol
Elev.
feet
980.8
Depth
feet
0.0
2
3
3
5
2
5
6
1/4
1/4
1/2
1 1/2
An open triangle in
the water level
(WL) column
indicates the depth
at which
groundwater was
observed while
drilling.
Groundwater levels
fluctuate.24
25
FILL
CL
ORGANIC CLAY, black, moist.
(Topsoil or Topsoil Fill)
SANDY LEAN CLAY, trace Gravel, seams of Silty Sand,
gray, moist to wet.
(Glacial Till)
With seams of Poorly Graded Sand at 19 feet.
END OF BORING.
Water observed at 14 feet while drilling.
Water observed at 6 feet with 19 1/2 feet of hollow-stem
auger in the ground.
Boring immediately backfilled with bentonite grout.
982.4
970.4
9.0
21.0
6/21/18 1" = 4'DATE:SCALE:DRILLER:
Tests or NotesWL
ST-6 page 1 of 1
3 1/4" HSA, AutohammerM. Takada
L O G O F B O R I N G
(See Descriptive Terminology sheet for explanation of abbreviations)LOCATION: See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-6
METHOD:
BORING:
BPF
Braun Intertec CorporationB1805858LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2018\05858.GPJ BRAUN_V8_CURRENT.GDT 6/29/18 09:21Braun Project B1805858
GEOTECHNICAL EVALUATION
Nelson Properties
7141 Galpin Boulevard
Chanhassen, Minnesota
qp
tsf
MC
%Symbol
Elev.
feet
991.4
Depth
feet
0.0
6
12
13
15
17
17
1 1/219
18
OL
CL
ORGANIC CLAY, with roots, black, moist.
(Topsoil)
SANDY LEAN CLAY, trace Gravel, with seams of Silty
Sand, brown, moist, medium to very stiff.
(Glacial Till)
END OF BORING.
Water not observed while drilling.
Boring immediately backfilled.
1017.2
1003.7
1.0
14.5
6/21/18 1" = 4'DATE:SCALE:DRILLER:
Tests or NotesWL
ST-7 page 1 of 1
3 1/4" HSA, AutohammerM. Takada
L O G O F B O R I N G
(See Descriptive Terminology sheet for explanation of abbreviations)LOCATION: See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-7
METHOD:
BORING:
BPF
Braun Intertec CorporationB1805858LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2018\05858.GPJ BRAUN_V8_CURRENT.GDT 6/29/18 09:21Braun Project B1805858
GEOTECHNICAL EVALUATION
Nelson Properties
7141 Galpin Boulevard
Chanhassen, Minnesota
qp
tsf
MC
%Symbol
Elev.
feet
1018.2
Depth
feet
0.0
6
4
3
7
7
7
1 1/4
1/4
1/4
22
28
26
OL
CL
CL
CL
CL
ORGANIC CLAY, black, moist.
(Topsoil)
LEAN CLAY with SAND, trace Gravel, grayish brown,
moist, medium.
(Glacial Till)
LEAN CLAY, grayish brown, moist, soft.
(Glacial Till)
SANDY LEAN CLAY, trace Gravel, grayish brown, moist,
soft to medium.
(Glacial Till)
SANDY LEAN CLAY, trace Gravel, gray, moist, medium.
(Glacial Till)
END OF BORING.
Water not observed while drilling.
Boring immediately backfilled.
1000.1
997.3
994.3
990.3
986.8
1.2
4.0
7.0
11.0
14.5
6/21/18 1" = 4'DATE:SCALE:DRILLER:
Tests or NotesWL
ST-8 page 1 of 1
3 1/4" HSA, AutohammerM. Takada
L O G O F B O R I N G
(See Descriptive Terminology sheet for explanation of abbreviations)LOCATION: See attached sketch.
(Soil-ASTM D2488 or D2487, Rock-USACE EM1110-1-2908)
Description of Materials
ST-8
METHOD:
BORING:
BPF
Braun Intertec CorporationB1805858LOG OF BORING N:\GINT\PROJECTS\AX PROJECTS\2018\05858.GPJ BRAUN_V8_CURRENT.GDT 6/29/18 09:21Braun Project B1805858
GEOTECHNICAL EVALUATION
Nelson Properties
7141 Galpin Boulevard
Chanhassen, Minnesota
qp
tsf
MC
%Symbol
Elev.
feet
1001.3
Depth
feet
0.0
Descriptive Terminology of Soil
Based on Standards ASTM D 2487-11/2488-09a
(Unified Soil Classification System)
Group
Symbol Group NameB
Cu ≥ 4 and 1 ≤ Cc ≤ 3D GW Well-graded gravelE
Cu < 4 and/or (Cc < 1 or Cc > 3)D GP Poorly graded gravelE
Fines classify as ML or MH GM Silty gravelE F G
Fines Classify as CL or CH GC Clayey gravelE F G
Cu ≥ 6 and 1 ≤ Cc ≤ 3D SW Well-graded sandI
Cu < 6 and/or (Cc < 1 or Cc > 3)D SP Poorly graded sandI
Fines classify as ML or MH SM Silty sandF G I
Fines classify as CL or CH SC Clayey sandF G I
CL Lean clayK L M
PI < 4 or plots below "A" lineJ ML SiltK L M
Organic OL
CH Fat clayK L M
MH Elastic siltK L M
Organic OH
PT Peat
Criteria for Assigning Group Symbols and
Group Names Using Laboratory TestsA
Soil Classification
Coarse-grained Soils (more than 50% retained on No. 200 sieve)Fine-grained Soils (50% or more passes the No. 200 sieve) Sands
(50% or more coarse
fraction passes No. 4
sieve)
Clean Gravels
(Less than 5% finesC)
Gravels with Fines
(More than 12% finesC)
Clean Sands
(Less than 5% finesH)
Sands with Fines
(More than 12% finesH)
Gravels
(More than 50% of
coarse fraction
retained on No. 4
sieve)
Highly Organic Soils
Silts and Clays
(Liquid limit less than
50)
Silts and Clays
(Liquid limit 50 or
more)
Primarily organic matter, dark in color, and organic odor
Inorganic
Inorganic
PI > 7 and plots on or above "A" lineJ
PI plots on or above "A" line
PI plots below "A" line
Liquid Limit −oven dried
Liquid Limit −not dried <0.75 Organic clay K L M N
Organic silt K L M O
Liquid Limit −oven dried
Liquid Limit −not dried <0.75 Organic clay K L M P
Organic silt K L M Q
Particle Size Identification
Boulders.............. over 12"
Cobbles................ 3" to 12"
Gravel
Coarse............. 3/4" to 3" (19.00 mm to 75.00 mm)
Fine................. No. 4 to 3/4" (4.75 mm to 19.00 mm)
Sand
Coarse.............. No. 10 to No. 4 (2.00 mm to 4.75 mm)
Medium........... No. 40 to No. 10 (0.425 mm to 2.00 mm)
Fine.................. No. 200 to No. 40
(0.075 mm to 0.425 mm)
Silt........................ No. 200 (0.075 mm) to .005 mm
Clay...................... < .005 mm
Relative ProportionsL, M
trace............................. 0 to 5%
little.............................. 6 to 14%
with.............................. ≥ 15%
Inclusion Thicknesses
lens............................... 0 to 1/8"
seam............................. 1/8" to 1"
layer.............................. over 1"
Apparent Relative Density of Cohesionless Soils
Very loose ..................... 0 to 4 BPF
Loose ............................ 5 to 10 BPF
Medium dense.............. 11 to 30 BPF
Dense............................ 31 to 50 BPF
Very dense.................... over 50 BPF
A.Based on the material passing the 3-inch (75-mm) sieve.
B.If field sample contained cobbles or boulders, or both, add "with cobbles or boulders,
or both" to group name.
C. 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
D.Cu = D60 / D10 Cc = 𝐷30 2 / (𝐷10 𝑥𝐷60)
E.If soil contains ≥ 15% sand, add "with sand" to group name.
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. Sands 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
I.If soil contains ≥ 15% gravel, add "with gravel" to group name.
J. If Atterberg limits plot in hatched area, soil is CL-ML, silty clay.
K.If soil contains 15 to < 30% 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” line.
Q.PI plots below “A” line
Laboratory Tests
DD Dry Density,pcf OC Organic content, %PL Plastic limit, %
WD Wet Density, pcf qp Pocket penetrometer strength LL Liquid limit, %
P200 % Passing #200 sieve MC Moisture conent, %PI Plasticity Index, %
Consistency of Blows Approximate Unconfined
Cohesive Soils Per Foot Compressive Strength
Very soft................... 0 to 1 BPF................... < 1/4 tsf
Soft........................... 2 to 4 BPF................... 1/4 to 1/2 tsf
Medium.................... 5 to 8 BPF .................. 1/2 to 1 tsf
Stiff........................... 9 to 15 BPF................. 1 to 2 tsf
Very Stiff................... 16 to 30 BPF............... 2 to 4 tsf
Hard.......................... over 30 BPF................ > 4 tsf
Drilling Notes:
BPF: Numbers indicate blows per foot recorded in standard
penetration test, also known as “N” value. The sampler was set
6 inches into undisturbed soil below the hollow-stem auger.
Driving resistances were then counted for second and third
6-inch increments, and added to get BPF.
Partial Penetration:If the sampler cannot be driven the full
12 inches beyond the initial 6-inch set, the number of blows for
that partial penetration is shown as "No./X" (i.e., 50/2"). If the
sampler cannot be advanced beyond the initial 6-inch set, the
depth of penetration will be recorded in the Notes column as
"No. to set X" (i.e., 50 to set 4").
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.
WL: WL indicates the water level measured by the drillers
either while drilling or following drilling.
Moisture Content:
Dry:Absence of moisture, dusty, dry to the touch.
Moist: Damp but no visible water.
Wet: Visible free water, usually soil is below water table.
5/2017