HomeMy WebLinkAbout14 Geotechnical Report 11012020MONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA
JOB NO. B18-008 November 2020
REPORT OF GEOTECHNICAL INVESTIGATION
CLIENT ENGINEER
Human Resource Development
Council of District IX
32 South Trace Avenue
Bozeman, MT 59715
Kyle Scarr, PE
Kyle.scarr@tdhengineering.com
234 East Babcock, Suite 3
Bozeman, MT 59715
REPORT OF GEOTECHNICAL INVESTIGATION
PROJECT NAME
PROJECT LOCATION 406.586.0277
tdhengineering.com
234 E. Babcock, Ste. 3
Bozem an, MT 59715
COMMUNITY FIRST GRIFFIN PLACE
206 EAST GRIFFIN DRIVE, BOZEMAN, MONTANA
11/13/2020
206 East Griffin Drive Table of Contents
Bozeman, Montana i
Table of Contents
1.0 EXECUTIVE SUMMARY .................................................................................................... 1
2.0 INTRODUCTION .................................................................................................................. 2
2.1 Purpose and Scope ....................................................................................................... 2
2.2 Project Description ........................................................................................................ 2
3.0 SITE CONDITIONS .............................................................................................................. 3
3.1 Geology and Physiography .......................................................................................... 3
3.2 Surface Conditions ........................................................................................................ 3
3.3 Subsurface Conditions .................................................................................................. 4
3.3.1 Soils .......................................................................................................................... 4
3.3.2 Ground Water ......................................................................................................... 7
4.0 ENGINEERING ANALYSIS ............................................................................................... 8
4.1 Introduction ..................................................................................................................... 8
4.2 Site Grading and Excavations ..................................................................................... 8
4.3 Foundation Systems ..................................................................................................... 9
4.3.1 Conventional Shallow Foundations ..................................................................... 9
4.3.2 Deep Foundation Options ................................................................................... 10
4.4 Foundation and Retaining Walls ............................................................................... 10
4.5 Interior Floor Slabs ...................................................................................................... 10
4.5 Exterior Concrete Flatwork ........................................................................................ 11
4.6 Pavements .................................................................................................................... 11
5.0 RECOMMENDATIONS ..................................................................................................... 13
5.1 Site Grading and Excavations ................................................................................... 13
5.2 Conventional Shallow Foundations on Structural Fill ............................................ 14
5.3 Foundation Walls ......................................................................................................... 16
5.4 Interior Floor Slabs ...................................................................................................... 16
5.5 Exterior Concrete Flatwork ........................................................................................ 17
5.6 Pavements .................................................................................................................... 18
5.8 Continuing Services .................................................................................................... 19
6.0 SUMMARY OF FIELD AND LABORATORY STUDIES .............................................. 21
6.1 Field Explorations ........................................................................................................ 21
6.2 Laboratory Testing ...................................................................................................... 21
7.0 LIMITATIONS ..................................................................................................................... 23
206 East Griffin Drive Appendix
Bozeman, Montana ii
APPENDIX
Boring and Test Pit Location Map (Figure 1)
Logs of Exploratory Borings and Test Pits (Figures 2 through 16)
Laboratory Test Data (Figures 17 and 31)
Schematic Footing and Slab Foundation Detail (Figure 32)
Soil Classification and Sampling Terminology for Engineering Purposes
Classification of Soils for Engineering Purposes
Community First Griffin Place Executive Summary
Bozeman, Montana Page 1
GEOTECHNICAL REPORT
COMMUNITY FIRST GRIFFIN PLACE
BOZEMAN, MONTANA
1.0 EXECUTIVE SUMMARY
The geotechnical investigation for the Community First Griffin Place project, generally encountered
uncontrolled fill on the western and central third of the site and native clay overlying sand and gravel
on the eastern third of the site. The fill was variable in both classification and relative density /
consistency. Additionally, the fill contained concrete, asphalt, and wooden debris. Based on historic
topographic maps, this fill is likely related to filling of an old pond previously located in the area.
The fill extended to depths of 19 feet in the borings performed and is anticipated to vary with the
shape of the historic pond bottom. The primary geotechnical concerns on this site include:
• The potential for settlement within the fill
• The potential for differential settlement across the variable fill
• The potential for unknown buried items or voids in the fill
• The potential for differential settlement between the areas with fill and the areas without fill.
Significant subgrade improvements will be necessary to control the overall settlement in the fill,
reduce risk of buried unknowns, and reduce differential settlements. The seismic site class for
the area is D, and the risk of seismically-induced liquefaction or soil settlement is considered
low and does not warrant additional evaluation.
Based on our understanding of the project and the concerns discussed above, it is our opinion that
all new building foundations and slab systems will require subsurface improvements comprised of:
• The complete removal of the surficial fine-grained soils down to native gravels and
replacement with properly compacted structural fill.
• The use of a specialized subsurface improvement system using Engineered Aggregate
Piers (EAP) to improve to fill soils and facilitate standard foundation construction over these
materials.
• The use of a reinforced structural fill matt to control differential settlement across the
structures.
We have also included recommendations for exterior concrete flatwork and asphalt pavement
systems for your consideration. In most cases, it is not practical or cost effective to completely
remove or improve poor soils, such as the fill encountered, beneath exterior site development
features. Also, these features are generally able to tolerate a higher level of potential movement
without experiencing detrimental impact to their function on the site. However, if the project is
unable or unwilling to accept any risk of potential vertical movements or distress to such exterior
features, the use of similar improvement methods, as discussed above, should be incorporated
throughout the project site.
Community First Griffin Place Introduction
Bozeman, Montana Page 2
2.0 INTRODUCTION
2.1 Purpose and Scope
This report presents the results of our geotechnical study for the proposed HRDC Community first
Griffin Place project located at 206 East Griffin Drive in Bozeman, Montana. This geotechnical study
has been prepared based on geotechnical investigations conducted in March 2018 and October
2020 across the limits of the project. The purpose of this study is to provide geotechnical
recommendations for the support of the proposed structures and design of the overall project.
Our field work included drilling seven borings and excavating eight test pits across the proposed
site. Samples were obtained from the borings and test pits and returned to our Great Falls
laboratory for testing. Laboratory testing was performed on selected soil samples to determine
engineering properties of the subsurface materials. The information obtained during our field
investigations and laboratory analyses was used to develop recommendations for the design of the
proposed foundation systems.
This study is in accordance with the proposal submitted by Mr. Kyle Scarr, PE of our firm dated
September 4, 2020. Our work was authorized to proceed by Mr. Martin Johnson of the Human
Resource Development Council (HRDC) of District IX by his email approval of our proposal.
2.2 Project Description
Based on the project’s informal review plans dated June 29, 2020, the project contains two building
(North and South) and associated parking lots, access drives, sidewalks, and landscaping. The
North Building is a two-story structure with a 26,700 square foot (sf) footprint being composed
largely of a warehouse, store, and office space. The South Building is a two-story structure with a
15,120 sf footprint containing living quarters. The proposed structures are anticipated to be slab-on-
grade, metal framed construction. Structural loads had not been developed at the time of this report.
However, for the purpose of our analysis, we have assumed that wall loads will be less than five
kips per lineal foot and column loads will be less than 200 kips.
Community First Griffin Place Site Conditions
Bozeman, Montana Page 3
3.0 SITE CONDITIONS
3.1 Geology and Physiography
The Bozeman area is predominantly characterized as surficial fine-grained clay of generally limited
thickness underlain by alluvial and gravel deposits. Alluvial deposits are generally concentrated in
proximity to Bridger Creek, Bozeman Creek, and the other small streams in and around Bozeman,
Montana. These deposits consist of variable blends of gravel, sand, silt, and clay. The gravel
deposits which make up much of the area are also variable deposits ranging from pebble to boulder
size and including lesser fractions of sand, silt, and clay. These formations are dominantly alluvial
terrace, abandoned channel and floodplain, remnant alluvial fan, and local glacial outwash deposits.
Significant areas of Upper Tertiary sediment or sedimentary rock formations are also encountered
at depth throughout Bozeman and the surrounding lands. These rock formations generally consist
of conglomerate, tuffaceous sandstone and siltstone, and marlstone.
Geologic Map of Montana, Edition 1.0 (2007)
Montana Bureau of Mines & Geology
Based on the subsurface conditions encountered, the site falls under seismic Site Class D. The
structural engineer should utilize the site classification above to determine the appropriate seismic
design data for use on this project in accordance with current applicable building codes. The
likelihood of seismically-induced soil liquefaction or settlement for this project is low and does not
warrant additional evaluation.
3.2 Surface Conditions
The proposed project site is located at 602 East Griffin Drive in Bozeman, Montana, and presently
consists of cleared areas resulting from demolition of existing structures, creation of equipment
Approximate
Site Location
Community First Griffin Place Site Conditions
Bozeman, Montana Page 4
staging and material storage areas, and undeveloped land. Historic information and our subsurface
observations indicate ponds used to be located on the western and central thirds of the site but
have been filled. Based on background information and site observations, the site is considered
relatively flat within the project limits; however, the topographic survey shows some areas of
moderately sloped terrain around drainage ditches in the northeast portion of the property and
through a heavily tree covered area extending from north to south in the center portion of the lot.
Development of the site for equipment storage has occurred since our geotechnical investigation
and the topographic survey was completed, and could vary from that described above.
3.3 Subsurface Conditions
3.3.1 Soils
The subsurface soil conditions are variable based on our exploratory excavating, drilling,
and soil sampling. In general, the subsurface soil conditions across the majority of the site
(central and western thirds) consist of fill materials extending to depth of approximately 19
feet. Based on historic topographic maps, this fill is likely related to filling of old ponds
located in the area. Because the fill is associated with filling ponds, the overall depth of fill is
anticipated to vary with the changes in the historic pond bottom elevation. The image below
taken from a USGS topographic map of the Bozeman area shows the approximate location
of the old ponds which is assumed to be the source of the fill encountered on site.
`
Bozeman, Montana USGS Map (MRC 45111F1)1
Community First Griffin Place Site Conditions
Bozeman, Montana Page 5
Fill was primarily encountered on the middle and western thirds of the site (B-1, B-2, B-3,
and TP-1 through TP-5). The easternmost third of the site encountered native soils which
consist of high-plasticity lean and fat clays overlying native gravel (B-4, B-5, B-6, B-7, and
TP-6 through TP-8). While the eastern third of the site was predominantly native materials,
limited depths of fill were noted in some borings and appears to be attributed to the recent
demolition of old structures in these areas. Due to extensive disturbances on the site,
topsoil or highly organic surface layers varied. Topsoil in some areas had been completely
stripped, other areas were composed of fill containing organics, while some areas contained
more typical topsoil characteristics. The borings were all terminated in native material
extending to depths of 31.5 feet below existing grade, the maximum depth investigated.
The subsurface soils are described in detail on the enclosed boring and test pit logs and are
summarized below. The stratification lines shown on the logs represent approximate
boundaries between soil types and the actual in situ transition may be gradual vertically or
discontinuous laterally.
FILL
Two distinct fill horizons were observed. The upper horizon varied from 1.5 feet to 18.0 feet
in thickness and was composed of sand, clay, and gravel in varying proportions. The
following upper fill material classifications were noted during our investigation:
• Clayey Sand with Gravel
• Lean Clay with Gravel
• Clayey Gravel with Sand
The relative density/consistency also varied throughout the upper fill horizon. This level of
variation is not uncommon for mass fill operations of uncontrolled fill. Organics and debris
including concrete, asphalt, wood, and glass were encountered through upper fill. The upper
fill is considered very loose/very soft to medium dense/firm based on penetration resistance
values which ranged from 2 to 27 blows per foot (bpf) and averaged 10 bpf. The natural
moisture contents varied from 4.5 to 30.3 percent and averaged 18.3 percent.
The lower fill horizon included a relatively thin (one to two-foot-thick) layer of elastic silt with
sand which is believed to be sediment that settled to the bottom of the historic ponds or
possibly a pond liner. The lower fill is considered stiff based on penetration resistance
values which ranged from ten to 15 bpf and averaged 13 bpf. A sample of the material
contained five percent gravel, 14 percent sand, and 81 percent silt and clay. The lower fill
exhibited a liquid limit of 57 percent and a plasticity index of 17 percent. The natural
moisture contents varied from 35.3 to 69.2 percent and averaged 23.9 percent.
Community First Griffin Place Site Conditions
Bozeman, Montana Page 6
Strong organic smells and areas of possible petroleum were noted during our investigation
within the fill material. An independent Phase II Environmental Site Assessment was
completed for the project by Resource Technologies, Inc.
TOPSOIL
Due to extensive disturbance to the site, consistent topsoil was not encountered. Topsoil
was noted during our 2018 investigation. Since that time, demolition of existing buildings
and development of equipment storage activities have occurred. Additionally, the presence
of fill over a large portion of the site has disrupted the natural development of topsoil on the
site. The fill areas general contain a highly organic surface layer which may not be
consistent with typical topsoil. The overall thickness of topsoil and/or highly organic surface
material varies significantly.
NATIVE CLAYS
Where existing fill associated with filling the old ponds was not encountered, high plasticity
native sandy lean clay and fat clay was encountered at or near the surface and extended to
depths of approximately four feet. The upper clay soils classified as fat clay in TP-7 and TP-
8 and high plasticity sandy lean clay in B-4, B-5, B-6, and B-7. The fat clay was considered
relatively stiff based on the effort required during excavation. Two samples of this material
exhibited liquid limits of 51 and 52 percent and plasticity indices of 23 and 25 percent,
respectively. The natural moisture contents of the fat clay ranged from 21 to 30 percent.
The lean clay is soft to very stiff as indicated by penetration resistance values which ranged
from 3 to 20 bpf and averaged 11 bpf. Two samples of the material contained 9 and 11
percent gravel, 30 and 31 percent sand, and 59 and 60 percent silt and clay. The sandy
lean clays exhibited a liquid limit of 35 and 45 percent and plasticity indices of 14 and 23
percent. The natural moisture contents varied from 12.8 to 19.1 percent and averaged 15.1
percent.
NATIVE SAND AND GRAVEL
Native sand and gravel was encountered at depth in all borings and in test pit TP-6, TP-7,
and TP-8. The sand and gravel were visually classified as poorly-graded gravel with sand,
clayey gravel with sand, and clayey sand with gravel. Seams of sandy lean clay with gravel
were encountered intermixed throughout this zone. The sandy lean clay was encountered in
relatively thin layers and had very stiff to hard consistencies. Because of these properties,
we are including these seams in the overall sand and gravel material description. The sand
and gravel is medium dense to very dense as indicated by penetration resistance values
which ranged from 16 to greater than 100 bpf and averaged 68 bpf. Samples of the material
contained between 25 and 52 percent gravel, between 24 and 40 percent sand, and
between 22 and 35 percent silt and clay. These gradations are not anticipated to be
completely representative of the actual in situ soil properties due to the inherent difficulties
with sampling these soils using drilling methods, which limit the size of rocks collected and
causes mechanical breaking of the rocks into smaller sizes. In situ materials are likely to be
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significantly gravellier than is represented by these tests. The sand and gravel exhibited
liquid limits between 30 and 44 percent and plasticity indices between 12 and 19 percent.
The natural moisture contents varied from 3.7 to 31.4 percent and averaged 14.8 percent.
3.3.2 Ground Water
Ground water was encountered in all of the borings and test pits with the exception of one
test pit. The following table summarizes the depth of ground water, ground surface
elevation, and resulting ground water elevation as observed during our field work.
Table 1 – Water Elevation Summary
Test Pit
Number
Water Depth
(ft)
Surface
Elevation (ft)
Water
Elevation (ft)
B-1 13.3 4,721.6 4,708.3
B-2 12.5 4,723.1 4,710.6
B-3 7.3 4,722.0 4,714.7
B-4 9.1 4,723.4 4,714.3
B-5 8.3 4,722.8 4,714.5
B-6 8.8 4,721.5 4,712.7
B-7 8.2 4,720.4 4,712.2
TP-1 11.0 4,721.6 4,710.6
TP-2 9.5 4,722.3 4,712.8
TP-3 ----- 4,721.2 -----
TP-4 9.8 4,722.4 4,712.6
TP-5 5.0 4,721.3 4,716.3
TP-6 6.0 4,723.7 4,717.7
TP-7 6.0 4,719.8 4,713.8
TP-8 7.0 4,722.9 4,715.9
Ground water monitoring devises were installed in two borings (B-1 and B-4) and three of
the completed test pits (TP-1, TP-5, & TP-7) and can be utilized for future ground water
monitoring. At the time of this report no additional data collection from these devices has
been performed. The water levels reported are those as observed at the time of drilling /
excavation. The presence or absence of observed ground water may be directly related to
the time of the subsurface investigation. Numerous factors contribute to seasonal ground
water occurrences and fluctuations, and the evaluation of such factors is beyond the scope
of this report.
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4.0 ENGINEERING ANALYSIS
4.1 Introduction
The primary geotechnical concerns regarding the proposed site are the significant and variable
thickness of fill material and the potentially expansive properties of the native clay. Significant
thicknesses of uncontrolled fill, such as those encountered on this site, can pose a significant
settlement risk to future construction. Generally, these fill deposits are very heterogeneous in terms
of their composition and density, which creates an elevated risk of differential movement. In
addition, deleterious materials such as wood and other degradable debris pose a long-term
settlement risk due to the decomposition of these items. While limited amounts of these degradable
materials were observed during our investigation, the fill is uncontrolled and may have increased
amounts of degradable material at depth or in locations which were not investigated.
Geotechnically, the potential risk for the project is partially related to the size of the proposed
structures; however, settlements can occur simply due to changes in soil moisture and even
lightweight construction can be impacted when built directly over uncontrolled fill deposits.
High-plasticity clay, such as the native soils encountered outside of the fill areas, pose some
expansive risk to the use of conventional shallow foundation and slab systems. These clay soils
are considered moisture-sensitive and can experience volume changes resulting from seasonal
moisture fluctuations. This shrink-swell behavior can impact lightly loaded shallow foundations but
poses the highest level of concern for interior and exterior slab-on-grade construction. These items
are impacted more significantly because they provide little or no dead load to help resist expansive
forces.
4.2 Site Grading and Excavations
The ground surface at the proposed site is considered relatively flat with limited areas of moderately
sloping terrain. Based on our field work, fill materials, native clay, or native sand and gravel are
anticipated in excavations. The actual materials encountered will depend completely on the
location on site. Ground water may be encountered in footing and utility excavations on this project.
Ground water was observed at depths ranging from 5.0 to 11.0 feet below existing site grades.
Many excavations associated with foundations and utility installation are anticipated to reach or
exceed these levels. In addition, the water levels observed at the time of our investigation may not
account for seasonal water fluctuations, and higher water levels are likely to be observed at other
times during the year. Thus, ground water should be anticipated in all excavations during
construction and may impact the proposed construction depending on the foundation depth and
configuration. Any structures incorporating full-depth basements should anticipate the need for
long-term dewatering systems or the consideration of uplift and buoyancy forces during the
structure design. Dewatering for structures or utilities may also encounter environmental
constraints and complexities depending on the outcome of the project’s environmental study.
Careful consideration of this possible constraint is warranted and could result in large economic
impacts.
Community First Griffin Place Engineering Analysis
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4.3 Foundation Systems
Based on our field work and review of the project site plan, the two proposed buildings will be
supported partially over known fill areas and partially over native soils. The variability in the bearing
substrate creates potential issues with respect to differential settlements which can adversely
impact the planned construction and warranted consideration.
4.3.1 Conventional Shallow Foundations
Considering the subsurface conditions encountered and the preliminary information
regarding the proposed construction, the use of conventional shallow foundation systems
are only anticipated to be viable in areas encountering native sand and gravel soils. In
these areas, conventional shallow foundations supported on the native sand and gravel or
on compacted structural fill extending to the native sand and gravel will provide the highest
level of performance for the structure.
Where existing fill is present, this material creates a considerable settlement risk, especially
for large commercial or multi-story construction. For this reason, the fill is not considered
suitable to support the proposed building systems without soil improvement. Subgrade
improvements may include over-excavation and replacement options, use of geosynthetic
reinforcement, engineered aggregate piers (EAP), or other methods which are capable of
mitigating the impacts of the uncontrolled fill. However, the selection of the appropriate
subgrade improvement option must consider the specifics regarding the proposed structure,
foundation loads, ground water conditions, and the quality of the fill which will impact the
constructability, long-term performance, and cost of these improvements. In some cases,
alternative deep foundation options may be more economical. Based on the fill depths
observed and the proximity of the ground water table, the complete removal and
replacement of the fill is not considered viable; thus, any subgrade improvement options
would likely be intended to control rather than eliminate the settlement risk.
Even with subgrade improvements within the fill zone, the risk of differential settlement
between portions of the structure supported over native soils and EAP improved fill remains.
In order to help control this risk, we advise that a minimum 18-inch zone of geosynthetically
reinforced structural fill be placed uniformly beneath the structure. The geosynthetic
material will provide lateral strength and help to distribute potential differential settlements
out to control their impact on the structure (See Figure 32). If no risk of differential
settlement can be accepted for these structures, then the complete removal and
replacement of the fill or the use of deep foundation alternatives capable of transmitting all
structures loads below the fill to native gravels is warranted for this project.
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4.3.2 Deep Foundation Options
Deep foundation options include driven and drilled piers, helical piers, and micro piles. Use
of these systems allow structural loads to extend through weak or unsuitable materials, such
as the fill encountered on this site, to more competent bearing material. We understand that
the use of slab-on-grade construction is preferred for this project. In order to support the
floors, extensive structural slabs and grade beams would be necessary to transfer floor
loads to the deep foundation elements. Based on preliminary discussions with the project
architects and structural engineers, deep foundation options are not the preferred
foundation system for the proposed buildings. Descriptions of possible deep foundation
options were included in the projects preliminary geotechnical report. Should deep
foundations become a desirable foundation option, we should be consulted to provide
specific recommendations for the foundation type anticipated.
4.4 Foundation and Retaining Walls
Foundation walls and other soil retaining structures which retain differential soil heights will be
subjected to horizontal loading due to lateral earth pressures. The lateral earth pressures are a
function of the natural and backfill soil types and acceptable wall movements, which affect soil strain
to mobilize the shear strength of the soil. More soil movement is required to develop greater internal
shear strength and lower the lateral pressure on the wall. To fully mobilize strength and reduce
lateral pressures, soil strain and allowable wall rotation must be greater for clay soils than for
cohesionless, granular soils.
The lowest lateral earth pressure against walls for a given soil type is the active condition and
develops when wall movements occur. Passive earth pressures are developed when the wall is
forced into the soil, such as at the base of a wall on the side opposite the retained earth side. When
no soil strain is allowed by the wall, this is the "at-rest" condition, which creates pressures having
magnitudes between the passive and active conditions.
Expansive soils, such as the fat clay present at this site, can generate high additional lateral
pressures on the walls if increases in soil moisture occur. Therefore, expansive soils should not be
used as backfill directly behind walls or remain within the lateral earth pressure wedge zone.
4.5 Interior Floor Slabs
The natural on-site soils and fill soils are not recommended for support of interior floor slabs.
Therefore, it will be necessary to improve the underslab conditions by removing and replacing the
high plasticity clay soils and/or providing subgrade soil improvements such as EAP. As discussed
in Section 4.3.1 above, the use of a uniform zone of geosynthetically reinforced structural fill is
necessary beneath the structure below the footing elevation in order to control potential differential
settlements. For this reason, material beneath interior slabs extending to the planned footing
elevation warrant excavation and should be replaced with properly compacted structural fill to
Community First Griffin Place Engineering Analysis
Bozeman, Montana Page 11
eliminate the risk of expansion and compaction difficulties associated with reusing these fine-
grained, moisture sensitive materials.
4.5 Exterior Concrete Flatwork
Exterior flatwork is generally more tolerable to vertical movement and can be repaired or replaced
more economically than interior slab systems. Thus, it is common for exterior flatwork applications
to utilize conventional construction consisting of a limited base course layer (four to six inches)
beneath the concrete surfacing. Similar construction is anticipated for this project assuming the
Owner is willing to accept the risk and understands the potential for future maintenance needs.
Additional risk of exterior flatwork is present as a result of the uncontrolled fill onsite. The cost of
improving the subgrade below exterior flatwork can be substantial. Typically, when poor soils are
encountered, there is a cost versus acceptable risk decision that must be made by the owner with
regard to exterior flatwork. Exterior sidewalk is less critical, has less stringent performance
expectations, and is easier to fix or replace if needed. The fill encountered onsite is variable in
material classification, relative density and consistency, and contains debris and organics that may
cause settlement if not improved. Thicker base course sections and geogrid improvements can be
implemented to reduce risk of settlement of exterior flatwork but will not eliminate the risk. If no
level of risk is acceptable for this project, extensive subgrade improvement measures, similar to
those recommended for the structures, are warranted beneath exterior flat work.
4.6 Pavements
A pavement section is a layered system designed to distribute concentrated traffic loads to the
subgrade. Performance of the pavement structure is directly related to the physical properties of the
subgrade soils and the magnitude and frequency of traffic loadings. The potential worst-case
subgrade materials are the existing uncontrolled fill and the native fat clay. The onsite fill is
generally classified as an A-2 soil in accordance with the American Association of State Highway
and Transportation Officials (AASHTO) classification. AASHTO considers this soil type to be a
relatively good subgrade material when encountered in a native condition; however, since this
material is an uncontrolled fill, it is susceptible to increased settlement, moisture sensitivity, and
instability which make it a concern for pavement systems. Similarly, the native fat clay which is
classified as an A-7 soil per AASHTO exhibits similar concerns as a subgrade stratum. Typical
California Bearing Ratio (CBR) values for these types of soil range from 2 to 5 percent for typical fat
clay and 20 to 40 percent for undisturbed native clayey gravels.
While the fill is a significant concern for buildings on the site, it may be acceptable under pavements
as the performance requirements are not as stringent. The fill will likely exhibit a lower CBR value
compared to similar native materials, and this will result in the need for increased pavement section
(asphalt and gravel) thicknesses on the project. A reinforcing geotextile between the subgrade and
the pavement gravels would help to prevent the upward migration of fines and the loss of aggregate
into the subgrade, and add structural improvement to the pavement section thereby prolonging the
integrity and performance of the pavement section. Similar to exterior flatwork, the cost of
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minimizing settlement risk associated with the fill versus the cost to improve must be made by the
owner. Performance of flexible asphalt pavements are generally tolerant of uniform subgrade
settlement. However, noticeable cracking and vertical displacement can occur in areas of high
differential movement, such as where native soils transition to fill. This risk is associated with the
considerable variation in the performance of these materials, and maintenance of the pavement
system at these locations could be required depending on the severity of the fill settlement. It is
also possible for noticeable settlement to occur as a result of conditions not represented in our
subsurface investigations as a result of the uncertainty associated with uncontrolled fill.
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Bozeman, Montana Page 13
5.0 RECOMMENDATIONS
5.1 Site Grading and Excavations
1. All topsoil and organic material, asphalt, concrete and related construction debris
associated with the demolition of the existing structures should be removed from the
proposed building and pavement areas and any areas to receive site grading fill.
Thicknesses of stripping will be dependent on the conditions at time of construction
and subject to variations across the site.
2. All fill and backfill should be non-expansive, free of organics and debris and should
be approved by the project geotechnical engineer. The on-site soils, exclusive of
topsoil and existing uncontrolled fill materials, are suitable for use as backfill and
general site grading fill on this project. All materials should be placed in uniform lifts
not exceeding 8 inches in thickness for fine-grained soils and not exceeding 12
inches for granular soils. All materials compacted using hand compaction methods
or small walk-behind units should utilize a maximum lift thickness of 6 inches to
ensure adequate compaction throughout the lift. All fill and backfill shall be moisture
conditioned to near the optimum moisture content and compacted to the following
percentages of the maximum dry density determined by a standard proctor test
which is outlined by ASTM D698 or equivalent (e.g. ASTM D4253-D4254).
a) Structural Fill Below Foundations ................................................ 98%
b) Structural Fill Below Slab-on-Grade Construction ...................... 98%
c) Exterior Foundation Wall Backfill ................................................. 95%
d) Below Paved Areas ..................................................................... 95%
e) General Landscaping or Nonstructural Areas ............................. 92%
f) Utility Trench Backfill .................................................................... 95%
For your consideration, native fine-grained soils are anticipated to be at moistures
contents well above the optimum for compaction and significant moisture
conditioning of these materials may be required prior to use. This often requires
abundant space where the soils can be worked and can be difficult during times of
the year when precipitation occurs frequently. Thus, the use of imported materials
for backfill may be more cost effective at times. Furthermore, verification of
compaction requires laboratory proctor tests to be performed on a representative
sample of the soil prior to construction. These tests can require up to one week to
complete (depending on laboratory backlog) and this should be considered when
coordinating the construction schedule to ensure that delays in construction or
additional testing expense is not required due to laboratory processing times or rush
processing fees.
Community First Griffin Place Recommendations
Bozeman, Montana Page 14
3. Imported structural fill should be non-expansive, free of organics and debris, and
conform to the material requirements outlined in Section 02234 of the Montana
Public Works Standard Specifications (MPWSS). All gradations outlined in this
standard are acceptable for use on this project; however, conventional proctor
methods (outlined in ASTM D698) shall not be used for any materials containing
less than 70 percent passing the ¾-inch sieve. Conventional proctor methods are
not suitable for these types of materials, and the field compaction value must be
determined using a relative density test outlined in ASTM D4253-4254.
4. Develop and maintain site grades which will rapidly drain surface and roof runoff
away from foundation and subgrade soils; both during and after construction. The
final site grading shall conform to the grading plan, prepared by others to satisfy the
minimum requirements of the applicable building codes.
5. It is the responsibility of the Contractor to provide safe working conditions in
connection with underground excavations. Temporary construction excavations
greater than four feet in depth, which workers will enter, will be governed by OSHA
guidelines given in 29 CFR, Part 1926. The soil conditions on site can change due
to changes in soils moisture or disturbances to the site prior to construction. Thus,
the contractor is responsible to provide an OSHA knowledgeable individual during
all excavation activities to regularly assess the soil conditions and ensure that all
necessary safety precautions are implemented and followed.
5.2 Conventional Shallow Foundations on Structural Fill
The design and construction criteria below should be observed for a shallow foundation system
bearing on properly compacted structural fill extending to native gravels or uncontrolled fill improved
with EAP. The EAP design must be performed by a licensed design/build contractor. We
recommend consulting either GeoTech Foundation Company (GTFC – West), First Mark
Construction, Keller North America, or Montana Helical Pier for the design and installation of this
system.
6. Where uncontrolled fill is encountered: Both interior and exterior footings should
bear on a minimum of 18 inches of properly compacted structural fill (Item 3) which
is separated from the underlying EAP improved fill using a Mirafi RS580i geotextile.
Foundations within the EAP improved zone shall be designed using the maximum
allowable bearing pressure to be issued by the EAP designer. For planning
purposes, we recommend using a slightly reduced bearing pressure than what is
generally seen with EAP. An allowable bearing pressure of 3,000 pounds per
square foot (psf) is recommended for preliminary structural design but the final
allowable bearing will ultimately depend on the EAP designer. EAP systems shall
be designed to limit total settlement to ¾-inch. EAP elements are anticipated to be
24 to 30 inches in diameter with lengths extending down into the native sand and
Community First Griffin Place Recommendations
Bozeman, Montana Page 15
gravel stratum. Alternative EAP sizes may be specified by the designer of record
based on their analysis.
Where uncontrolled fill is not encountered: Both interior and exterior footings
should bear on a minimum of 18 inches of properly compacted structural fill (Item 3)
overlying a Mirafi RS580i geotextile. If native gravels are not encountered at the
geotextile elevation, additional removal and replacement with structural fill must be
performed to reach the native gravel. Depending on final building and footing
elevations, it may be necessary to over excavate native gravels to allow for the
required structural fill and reinforcing geotextile. All structural fill shall be placed and
compacted in accordance with item 2 above. The limits of removal and replacement
with compacted structural fill shall extend at least one foot beyond the outer face of
the footings in all directions. Footings supported as described should be designed
with a maximum allowable soil bearing pressure of 3,000 psf and a one-third
increase in the bearing pressure is acceptable for consideration of transient load
cases. Such construction is expected to realize total settlements of less than ¾-
inch with differential settlements of approximately one-half this amount.
The uniform structural fill layer with a minimum 18-inch thickness and underlying
Mirafi RS580i geotextile is designed to be a reinforced mat to limit differential
settlement across the building due to the varying subgrade conditions. The
reinforced structural fill layer shall be placed under the entirety of the buildings and
extend one foot beyond the outer face of the perimeter footings. The structural fill
layer shall meet the requirements of Items 2 and 3 above. The subgrade fill should
be compacted to it is highest achievable density given the in situ moisture content
prior to placing the reinforcing geotextile. A schematic representation of this system
has been included as Figure 32 in the Appendix.
7. Footings shall be sized to satisfy the minimum requirements of the applicable
building codes while not exceeding the maximum allowable bearing pressure
provided in Item 6 above.
8. Exterior footings and footings beneath unheated areas should be placed at least 48
inches below finished exterior grade for frost protection.
9. Lateral loads are resisted by sliding friction between the footing base and the
supporting soil and by lateral pressure against the footings opposing movement.
For design purposes, a friction coefficient of 0.45 and a lateral resistance pressure
of 150 psf per foot of depth are appropriate for foundations bearing on properly
compacted structural fill (Item 3) and backfilled with processed and compacted on-
site soils.
Community First Griffin Place Recommendations
Bozeman, Montana Page 16
10. A representative of TD&H Engineering should be retained to observe construction
excavations, verify that all excavations have reached suitable native gravels, and
verify the placement and compaction of the structural fill in accordance with these
recommendations.
11. The EAP designer / installer shall provide their own internal quality control system.
At a minimum, the installer shall record date, time, length, lift thicknesses, and
elevation for each pier installed. Additionally, the results of the test piers and
performance testing shall be documented. The International Building Code (IBC)
considers EAPs to be a form of deep foundation which require full-time inspection.
Prior to placing structural fill or footings on EAP improved soils, the designer /
installer shall provide a certification stamped by a Montana Licensed Professional
Engineer stating that the piers were properly installed and are capable of meeting
the performance requirements noted in Item 6. The certification letter shall include
all testing and internal quality control data.
12. Ground water is anticipated in excavations and EAP installation holes. Ground
water elevations will vary depending on the time of year and the magnitude of
seasonal ground water fluctuations. The contractor should be prepared to dewater
as needed to facilitate the installation of utilities, foundations, and EAP systems. We
recommend dewatering to an elevation below the bottom of the EAP to ease
installation.
5.3 Foundation Walls
13. Backfill should be selected, placed, and compacted per Item 2 above. Care should
be taken not to over-compact the backfill since this could cause excessive lateral
pressure on the walls. Only hand-operated compaction equipment should be used
within 5 feet of foundation walls.
14. Exterior footing drains are only required for structures which incorporate a below
grade space (basement, crawlspace, etc.) or any structure in which the interior floor
elevation is set lower than the finished exterior grade. Exterior floor drains are not
required with the proposed slab-on-grade construction being used for these
buildings.
5.4 Interior Floor Slabs
15. Interior floor slabs will be supported at depth on the reinforced structural fill mat
noted in Item 6 above. Structural fill meeting the requirements of Items 2 and 3
above should be used between the bottom of the interior floor slabs and the
structural fill mat. A maximum of 12 inches of angular, crushed, ¾” washed rock is
acceptable directly beneath the slabs for plumbing and utility installation.
Community First Griffin Place Recommendations
Bozeman, Montana Page 17
16. Concrete floor slabs should be designed using a modulus of vertical subgrade
reaction no greater than 400 pci when designed and constructed as recommended
in Item 15 above.
17. Geotechnically, an underslab vapor barrier is not required for this project. A vapor
barrier is normally used to limit the migration of soil gas and moisture into occupied
spaces through floor slabs. The need for a vapor barrier should be determined by
the architect and/or structural engineer based on interior improvements and/or
moisture and gas control requirements.
5.5 Exterior Concrete Flatwork
As noted in the Engineering Analysis, there is inherent risk when building on uncontrolled fill.
The following recommendations assume the owner is willing to accept this risk.
15. For normally loaded, exterior concrete flatwork, the fine-grained (clay and silt) soils
and uncontrolled fill encountered pose some risk to the performance of these
features due to the compressibility and frost susceptibility of these materials.
Conventional construction consisting of approximately four to six inches of free-
draining, crushed gravel placed beneath the concrete and compacted to the
requirements of Item 2 above is considered suitable provided the Owner is willing to
accept the risks associated with this construction method. The magnitude of
displacement will vary depending the depth of the fine-grained soils and
uncontrolled fill at the location as well as the relative density / consistency of the fill.
Additional factors that could affect overall displacement include drainage conditions,
irrigation locations, and slab loading conditions. Slab movements could result in the
need for more frequent repair or replacement of the exterior concrete if they become
too great.
16. Prior to placing exterior concrete flatwork, the top 12 inches of subgrade should be
scarified and recompacted to the requirements of Item 2.
17. If the Owner desires to reduce the risk of movements beneath exterior slab systems
and improve anticipated performance, a variety of measures are possible, and these
can be discussed with the design team. Mitigative efforts can range from the use of
a greater base course thickness, EAP improvements, and the complete removal and
replacement of the problematic soil. The various options need to be considered by
the Owner based on the performance to cost relationship so they can select the
most appropriate system for their project.
Community First Griffin Place Recommendations
Bozeman, Montana Page 18
5.6 Pavements
18. The following pavement section or an approved equivalent section should be
selected in accordance with the discussions in the Engineering Analysis.
Table 2 – Recommended Asphalt Section
Pavement Component Component Thickness
Asphaltic Concrete Pavement 3”
Crushed Base Course 6”
Crushed Subbase Course 18”
Geotextile Type Mirafi RS580i
Total 27”
** The pavement sections summarized above have not considered vehicle loads associated with construction activities and are
not intended to be utilized by the contractor during construction for access to concrete trucks, cranes, or other heavy
equipment. Additional assessment of improvements to support such traffic would be needed and is beyond the scope of this
report.
19. Final pavement thicknesses exceeding three inches shall be constructed in two
uniform lifts.
20. Crushed base courses shall conform to the material properties outlined in Section
02235 of the Montana Public Works Standard Specifications (MPWSS). All
gradations outlined in this specification are acceptable for this application based on
the local availability and contractor preference.
Crushed subbase courses shall conform to material properties outlined in Section
02234 of the MPWSS. All gradations outlined in this specification are acceptable for
this application based on local availability and contractor preference.
21. Where the existing grades will be raised more than the thickness of the pavement
section, all fill should be placed, compacted and meet the general requirements
given in Item 2 above. This may require moisture conditioning if native soils are
used for general site grading fill.
22. Prior to geotextile installation, the top 12 inches of subgrade should be scarified and
compacted to the highest achievable level given the in situ moisture content and
Community First Griffin Place Recommendations
Bozeman, Montana Page 19
must be cleared of all loose soil and statically rolled to provide a smooth, relatively
level surface.
23. Ideally, the asphaltic cement should be a Performance Graded (PG) binder having
the following minimum high and low temperature values based on the desired
pavement reliability.
Reliability Min. High
Temp Rating
Min. Low
Temp Rating Ideal Oil Grade
50% 33.8 -30.6 PG 52-34
98% 37.5 -39.4 PG 52-40
However, based on our experience neither of these materials are available through
local suppliers, and significant additional expense would be realized using these
products. Thus, we recommend the use of a PG 58-28 oil for any asphalt pavement
included in this project. Of the locally available products, this material will provide
the highest level of performance in our climatic conditions.
5.8 Continuing Services
Three additional elements of geotechnical engineering service are important to the successful
completion of this project.
24. Consultation between the geotechnical engineer and the design professionals
during the design phases is highly recommended. This is important to ensure that
the intentions of our recommendations are incorporated into the design, and that
any changes in the design concept consider the geotechnical limitations dictated by
the on-site subsurface soil and ground water conditions.
25. Observation, monitoring, and testing during construction is required to document the
successful completion of all earthwork and foundation phases. A geotechnical
engineer from our firm should be retained to observe the excavation, earthwork, and
foundation phases of the work to determine that subsurface conditions are
compatible with those used in the analysis and design. If construction services are
performed by someone other than our firm, the entities performing these services
must be directed to contact us immediately upon changes in subsurface conditions
so we may re-evaluate our recommendations in a timely manner.
26. During site grading, placement of all fill and backfill should be observed and tested
to confirm that the specified density has been achieved. We recommend that the
Owner maintain control of the construction quality control by retaining the services of
an experienced construction materials testing laboratory. We are available to
provide construction inspection services as well as materials testing of compacted
Community First Griffin Place Recommendations
Bozeman, Montana Page 20
soils and the placement of Portland cement concrete and asphalt. In the absence of
project specific testing frequencies, TD&H recommends the following minimum
testing frequencies be used:
Compaction Testing
Beneath Column Footings 1 Test per Footing per Lift
Beneath Wall Footings 1 Test per 50 LF of Wall per Lift
Beneath Slabs 1 Test per 1,500 SF per Lift
Foundation Backfill 1 Test per 100 LF of Wall per Lift
Parking Lot & Access Roads 1 Test per 2,500 SF per Lift
LF = Lineal Feet SF = Square Feet
206 East Griffin Drive Summary of Field & Laboratory Studies
Bozeman, Montana Page 21
6.0 SUMMARY OF FIELD AND LABORATORY STUDIES
6.1 Field Explorations
The field exploration programs were conducted on March 3, 2018, and October 21-22, 2020. A total
of seven borings and eight test pits were drilled / excavated to depths ranging from 9.2 to 31.5 feet
at the locations shown on Figure 1 to observe subsurface soil and ground water conditions. The
borings were drilled using a Mobile B-61 drill rig equipped with eight-inch hollow stem augers and
the tests pits were excavated using a Komatsu 170LC excavator. The subsurface exploration and
sampling methods used are indicated on the attached boring and test pit logs. The borings were
logged by Mr. Craig Nadeau, PE and the test pits were logged by Mr. Ahren Hastings, PE of TD&H
Engineering. The location and elevation of the borings and test pits were determined by TD&H
survey personnel during a site wide topographic survey. Due to demolition and development of an
equipment storage yard, current surface elevation at some or all boring and test pit locations may
have changed.
Samples of the subsurface materials were taken using 1⅜-inch I.D. split spoon samplers. The
samplers were driven 18 inches, when possible, into the various strata using a 140-pound drop
hammer falling 30 inches onto the drill rods. For each sample, the number of blows required to
advance the sampler each successive six-inch increment was recorded, and the total number of
blows required to advance the sampler the final 12 inches is termed the penetration resistance (“N-
value”). This test is known as the Standard Penetration Test (SPT) described by ASTM D1586.
Penetration resistance values indicate the relative density of granular soils and the relative
consistency of fine-grained soils. Logs of all soil borings and test pits, which include soil
descriptions, sample depths, and penetration resistance values, are presented on the Figures 2
through 16. Composite grab samples of the subsurface materials were taken from the spoils
removed during drilling and excavation at discrete sampling locations selected by the onsite
engineer.
Measurements to determine the presence and depth of ground water were made in the borings by
lowering an electronic water sounder through the open boring or auger shortly after the completion
of drilling. Measurements to determine the depth of ground water in the test pits were made using a
steel tape measure shortly after the completion of excavating.
6.2 Laboratory Testing
Samples obtained during the field exploration were returned to our materials laboratory where they
were observed and visually classified in general accordance with ASTM D2487, which is based on
the Unified Soil Classification System. Representative samples were selected for testing to verify
field classifications and were performed in general accordance with ASTM or other approved
procedures.
206 East Griffin Drive Summary of Field & Laboratory Studies
Bozeman, Montana Page 22
Tests Conducted: To determine:
Natural Moisture Content Representative moisture content of soil at the time of
sampling.
Grain-Size Distribution Particle size distribution of soil constituents describing the
percentages of clay/silt, sand and gravel.
Atterberg Limits A method of describing the effect of varying water content on
the consistency and behavior of fine-grained soils.
The laboratory testing program for this project consisted of 75 moisture-visual analyses, seven
sieve (grain-size distribution) analyses, and eight Atterberg Limits analyses. The results of the water
content analyses are presented on the boring and test pit logs, Figures 2 through 16. The grain-
size distribution curves and Atterberg limits are presented on Figures 17 through 31.
206 East Griffin Drive Limitations
Bozeman, Montana Page 23
7.0 LIMITATIONS
This report has been prepared in accordance with generally accepted geotechnical engineering
practices in this area for use by the client for design purposes. The findings, analyses, and
recommendations contained in this report reflect our professional opinion regarding potential
impacts the subsurface conditions may have on the proposed project and are based on site
conditions encountered. Our analysis assumes that the results of the exploratory test pits and
borings are representative of the subsurface conditions throughout the site, that is, that the
subsurface conditions everywhere are not significantly different from those disclosed by the
subsurface study. Unanticipated soil conditions are commonly encountered and cannot be fully
determined by a limited number of soil borings, test pits, and laboratory analyses. Such unexpected
conditions frequently require that some additional expenditures be made to obtain a properly
constructed project. Therefore, some contingency fund is recommended to accommodate such
potential extra costs. The potential for unexpected or undiscovered subsurface soil conditions is
increased on sites containing undocumented fill, such as was found on this project. There is
inherent risk of objectionable performance with building and sitework placed on fill regardless of the
mitigation measures recommended in this report. If the owner is unwilling to accept this risk, the
development should be modified to avoid fill areas.
The recommendations contained within this report are based on the subsurface conditions
observed in the borings and test pits and are subject to change pending observation of the actual
subsurface conditions encountered during construction. TD&H cannot assume responsibility or
liability for the recommendations provided if we are not provided the opportunity to perform limited
construction inspection and confirm the engineering assumptions made during our analysis. A
representative of TD&H should be retained to observe all construction activities associated with
subgrade preparation, foundations, and other geotechnical aspects of the project to ensure the
conditions encountered are consistent with our assumptions. Unforeseen conditions or undisclosed
changes to the project parameters or site conditions may warrant modification to the project
recommendations.
Long delays between the geotechnical investigation and the start of construction increase the
potential for changes to the site and subsurface conditions which could impact the applicability of
the recommendations provided. If site conditions have changed because of natural causes or
construction operations at or adjacent to the site, TD&H should be retained to review the contents of
this report to determine the applicability of the conclusions and recommendations provide
considering the time lapse or changed conditions.
Misinterpretation of the geotechnical information by other design team members is possible and can
result in costly issues during construction and with the final product. Our geotechnical engineers
are available upon request to review those portions of the plans and specifications which pertain to
earthwork and foundations to determine if they are consistent with our recommendations and to
suggest necessary modifications as warranted. This service was not included in the original scope
of the project and will require additional fees for the time required for specification and plan
206 East Griffin Drive Limitations
Bozeman, Montana Page 24
document review and comment. In addition, TD&H should be involved throughout the construction
process to observe construction, particularly the placement and compaction of all fill, preparation of
all foundations, and all other geotechnical aspects. Retaining the geotechnical engineer who
prepared your geotechnical report to provide construction observation is the most effective method
of managing the risks associated with unanticipated conditions.
This report was prepared for the exclusive use of the owner and architect and/or engineer in the
design of the subject facility. It should be made available to prospective contractors and/or the
contractor for information on factual data only and not as a warranty of subsurface conditions such
as those interpreted from the boring logs and presented in discussions of subsurface conditions
included in this report.
Prepared by: Reviewed by:
Kyle Scarr PE Craig Nadeau PE
Geotechnical Engineer Geotechnical Manager
TD&H ENGINEERING TD&H ENGINEERING
REVISIONSHEETDESIGNED BY:QUALITY CHECK:JOB NO.FIELDBOOKDRAWN BY:DATE:B18-008 FIGURE 1REV DATE
COMMUNITY FIRST GRIFFIN PLACE
BOZEMAN, MONTANA
FIGURE 1
BORING/TEST PIT LOCATIONS B18-0082020.11.11187/48.DWGF1SEJKLS406.586.0277 • tdhengineering.com
Engineering
234 E. BABCOCK ST., SUITE 3 • BOZEMAN, MONTANA 59715
0
2.5
5
7.5
10
12.5
15
17.5
FILL: Clayey SAND with Gravel, loose to medium
dense, dark brown to black, moist, pieces of concrete,
asphalt, and glass observed
- Upper 12 to 18 inches contains high levels of
organic material.
- Scattered sandy clay and clayey sand zones
through the fill
FILL: Elastic SILT with Sand, very soft, black, very
moist, strong organic odor, probable old pond bottom
sediments
Clayey GRAVEL with Sand, dense to very dense,
brown, wet
Clayey SAND with Gravel, very dense, moist, olive
14.5
16.5
18.3
7-5-5
5-6-7
5-3-3
3-9-15
33-4-3
3-1-9
11-14-
17
LEGEND LOG OF SOIL BORING B-1SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 21, 2020 B18-008
No sample recovery Figure No. 2
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Stripped Soil & Loose Gravel
SURFACE ELEVATION:4,721.6 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
1 of 2
20
22.5
25
27.5
30
32.5
35
brown
Sandy Lean CLAY with Gravel, very stiff to hard, light
brown, moist
Bottom of Boring - Monitoring Well Installed.
29.0
31.5
22-30-
50/2.5"
12-28-
50/5"
7-15-21
80/8.5"
78/11"
LEGEND LOG OF SOIL BORING B-1SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 21, 2020 B18-008
No sample recovery Figure No. 2
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Stripped Soil & Loose Gravel
SURFACE ELEVATION:4,721.6 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
2 of 2
0
2.5
5
7.5
10
12.5
15
17.5
FILL: Lean CLAY with Gravel, very soft to firm, brown
to black, moist, slight organic odor, pieces of wood
and concrete observed
- Upper 12 to 18 inches contains high levels of
organic material.
- Large piece of wood in spoon tip at 14.0 feet
FILL: Elastic SILT with Sand, very soft, black, very
moist, strong organic odor, probable old pond bottom
18.0
5-5-1
4-2-2
1-1-2
0-1-1
0-2-4
2-4-4
0-4-11 69.257
LEGEND LOG OF SOIL BORING B-2SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 21, 2020 B18-008
No sample recovery Figure No. 3
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,723.1 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
1 of 2
20
22.5
25
27.5
30
32.5
35
sediments
Clayey SAND with Gravel, medium dense to very
dense, moist, light brown
Bottom of Boring
19.0
30.8
33-11-
11
21-41-
50
25-50/
4"
91
50/4"
LEGEND LOG OF SOIL BORING B-2SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 21, 2020 B18-008
No sample recovery Figure No. 3
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,723.1 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
2 of 2
0
2.5
5
7.5
10
12.5
15
17.5
FILL: Clayey SAND with Gravel, very loose to
medium dense, dark brown to black, slightly moist to
wet, pieces of concrete observed
- Upper 12 to 18 inches contains high levels of
organic material.
- Zones of very soft lean clay throughout fill zone
- Concrete in sample at 7.5 feet
- Pushed rock or debris with spoon
FILL: Elastic SILT with Sand, very soft, black, very
moist, strong organic odor, probable old pond bottom
sediments
Sandy Lean CLAY with Gravel, very stiff, light brown,
moist
16.0
18.0
BULK
8-9-7
9-3-2
0-9-18
23-14-6
10-4-11
2-2-2
6-10-13
G
LEGEND LOG OF SOIL BORING B-3SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 22, 2020 B18-008
No sample recovery Figure No. 4
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Snow Covered Native Grasses
SURFACE ELEVATION:4,722.0 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
1 of 2
20
22.5
25
27.5
30
32.5
35
Clayey SAND with GRAVEL, very dense, brown,
wet, high fines content
Bottom of Boring
25.5
31.4
5-7-12
19-50/
3"
12-36-
50/4"
50/3"
86/10"
LEGEND LOG OF SOIL BORING B-3SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 22, 2020 B18-008
No sample recovery Figure No. 4
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Snow Covered Native Grasses
SURFACE ELEVATION:4,722.0 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
2 of 2
0
2.5
5
7.5
10
12.5
15
17.5
Sandy Lean CLAY, appears firm, dark brown, moist
- Upper 12 to 18 inches contains high levels of
organic material.
Clayey GRAVEL with Sand, medium dense to very
dense, brown, slightly moist
4.0
5-3-8
11-12-
14
22-31-
33
26-40-
34
17-22-
21
64
74
LEGEND LOG OF SOIL BORING B-4SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 21, 2020 B18-008
No sample recovery Figure No. 5
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,723.4 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
1 of 2
20
22.5
25
27.5
30
32.5
35
Lean CLAY with Sand, very stiff, brown, moist
Bottom of Boring - Install Monitoring Well
28.0
31.5
50/4.5"
28-50/
5"
8-13-18
50/4.5"
50/5"
LEGEND LOG OF SOIL BORING B-4SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 21, 2020 B18-008
No sample recovery Figure No. 5
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,723.4 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
2 of 2
0
2.5
5
7.5
10
12.5
15
17.5
Sandy Lean CLAY, appears firm to soft, dark brown
to brown, moist
- Upper 12 to 18 inches contains high levels of
organic material.
Clayey GRAVEL with Sand, dense to very dense,
brown, moist to wet
Sandy Lean CLAY, appears stiff, brown, moist
4.5
18.0
2-2-1
14-20-
15
BULK
30-33-
39
25-30-
23
18-24-
23
G
72
53
LEGEND LOG OF SOIL BORING B-5SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 22, 2020 B18-008
No sample recovery Figure No. 6
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Snow Covered Native Grasses
SURFACE ELEVATION:4,722.8 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
1 of 2
20
22.5
25
27.5
30
32.5
35
Clayey GRAVEL with Sand, very dense, brown, moist
Bottom of Boring
20.0
25.4
17-50/
5"
50/5"
50/5"
50/5"
LEGEND LOG OF SOIL BORING B-5SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 22, 2020 B18-008
No sample recovery Figure No. 6
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Snow Covered Native Grasses
SURFACE ELEVATION:4,722.8 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
2 of 2
0
2.5
5
7.5
10
12.5
15
17.5
FILL: Clayey SAND with Gravel, appears loose,
black, moist, large piece of scrap metal buried in soil
- Upper 12 to 18 inches contains high levels of
organic material.
Sandy Lean CLAY, stiff, brown, moist
Clayey GRAVEL with Sand, dense to very dense,
brown, moist to wet
1.5
4.0
BULK
4-4-5
8-15-20
18-25-
30
28-30-
32
19-23-
50
G
55
62
73
LEGEND LOG OF SOIL BORING B-6SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 22, 2020 B18-008
No sample recovery Figure No. 7
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Snow Covered Native Grasses
SURFACE ELEVATION:4,721.5 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
1 of 2
20
22.5
25
27.5
30
32.5
35
Bottom of Boring
25.8
50/5"
23-50/
4"
50/5"
50/4"
LEGEND LOG OF SOIL BORING B-6SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 22, 2020 B18-008
No sample recovery Figure No. 7
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Snow Covered Native Grasses
SURFACE ELEVATION:4,721.5 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
2 of 2
0
2.5
5
7.5
10
12.5
15
17.5
Sandy Lean CLAY, appears firm, brown, moist
- Upper 12 to 18 inches contains high levels of
organic material.
Clayey GRAVEL with Sand, medium dense to very
dense, brown, moist to wet
3.5
3-4-16
14-9-7
36-50/
3"
20-22-
27
25-24-
49
50/3"
73
LEGEND LOG OF SOIL BORING B-7SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 22, 2020 B18-008
No sample recovery Figure No. 8
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Snow Covered Native Grasses
SURFACE ELEVATION:4,720.4 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
1 of 2
20
22.5
25
27.5
30
32.5
35
Bottom of Boring
25.8
50/2"
41-50/
3"
50/2"
50/3"
LEGEND LOG OF SOIL BORING B-7SPT blows per foot Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
1-3/8-inch I.D. split spoon Logged by:Craig Nadeau, PE
2-1/2-inch I.D. split spoon Drilled by:O'Keefe Drilling
Truck-mounted Mobile B-61 with 8-inch HSA2-1/2-inch I.D. ring sampler GNP = Granular and Nonplastic
3-inch I.D. thin-walled sampler Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
October 22, 2020 B18-008
No sample recovery Figure No. 8
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Snow Covered Native Grasses
SURFACE ELEVATION:4,720.4 feet
DEPTH (FT)GROUNDWATERSPT BLOWCOUNTSSAMPLEDEPTH (FT)PENETRATION RESISTANCE/MOISTURE CONTENT
0 10 20 30 40 50
= BLOWS PER FOOT
= MOISTURE CONTENT
2 of 2
0
2.5
5
7.5
10
12.5
15
17.5
TOPSOIL: Lean CLAY, appears stiff, dark brown, moist to
frozen, organics
FILL: Clayey GRAVEL with Sand, appears medium dense,
brown, moist to saturated, contains construction debris
- Upper zone of fill contains elevated organics to a total
depth of 12 to 18 inches.
Bottom of Test Pit
0.4
14.2
LEGEND LOG OF TEST PIT TP-1Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Ahren Hastings, PE
Excavated by:Earth Surgeons
Komatsu 170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 3, 2018 B18-008
Figure No. 9
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,721.6 feet
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
0
2.5
5
7.5
10
12.5
15
17.5
TOPSOIL: Lean CLAY, appears stiff, dark brown, moist to
frozen, organics
FILL: Clayey GRAVEL with Sand, appears medium dense,
brown, moist to saturated, contains construction debris
- Upper zone of fill contains elevated organics to a total
depth of 12 to 18 inches.
Petroleum Odor Detected
Bottom of Test Pit
0.3
11.1
G
G
LEGEND LOG OF TEST PIT TP-2Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Ahren Hastings, PE
Excavated by:Earth Surgeons
Komatsu 170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 3, 2018 B18-008
Figure No. 10
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,722.3 feet
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
0
2.5
5
7.5
10
12.5
15
17.5
TOPSOIL: Lean CLAY, appears stiff, dark brown, moist to
frozen, organics
FILL: Clayey GRAVEL with Sand, appears medium dense,
brown, moist to saturated, contains construction debris
- Upper zone of fill contains elevated organics to a total
depth of 12 to 18 inches.
Bottom of Test Pit
0.2
12.0
Ground
water
not
encoun-
tered
LEGEND LOG OF TEST PIT TP-3Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Ahren Hastings, PE
Excavated by:Earth Surgeons
Komatsu 170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 3, 2018 B18-008
Figure No. 11
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,721.2 feet
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
0
2.5
5
7.5
10
12.5
15
17.5
TOPSOIL: Lean CLAY, appears stiff, dark brown, moist to
frozen, organics
FILL: Clayey GRAVEL with Sand, appears medium dense,
brown, moist to saturated, contains construction debris
- Upper zone of fill contains elevated organics to a total
depth of 12 to 18 inches.
Petroleum Odor Detected
Bottom of Test Pit
0.6
11.5
G
G
LEGEND LOG OF TEST PIT TP-4Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Ahren Hastings, PE
Excavated by:Earth Surgeons
Komatsu 170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 3, 2018 B18-008
Figure No. 12
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,722.4 feet
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
0
2.5
5
7.5
10
12.5
15
17.5
TOPSOIL: Lean CLAY, appears stiff, dark brown, moist to
frozen, organics
FILL: Clayey GRAVEL with Sand, appears medium dense,
brown, moist to saturated, contains construction debris
- Upper zone of fill contains elevated organics to a total
depth of 12 to 18 inches.
Bottom of Test Pit
0.5
10.5
LEGEND LOG OF TEST PIT TP-5Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Ahren Hastings, PE
Excavated by:Earth Surgeons
Komatsu 170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 3, 2018 B18-008
Figure No. 13
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,721.3 feet
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
0
2.5
5
7.5
10
12.5
15
17.5
Poorly-Graded GRAVEL with Sand appears dense, brown
and gray, slightly moist to saturated
- Upper 12 to 18 inches contains high levels of organic
material.
Bottom of Test Pit
9.2
G
G
LEGEND LOG OF TEST PIT TP-6Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Ahren Hastings, PE
Excavated by:Earth Surgeons
Komatsu 170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 3, 2018 B18-008
Figure No. 14
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,723.7 feet
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
0
2.5
5
7.5
10
12.5
15
17.5
TOPSOIL: Lean CLAY, appears stiff, dark brown moist to
frozen, organics
Fat CLAY, appears stiff, brown, slightly moist
qu = 3.0 tsf
Poorly-Graded GRAVEL with Sand, appears dense, brown
and gray, slightly moist to saturated
Bottom of Test Pit
1.5
4.2
10.5
G
G
G
51
LEGEND LOG OF TEST PIT TP-7Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Ahren Hastings, PE
Excavated by:Earth Surgeons
Komatsu 170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 3, 2018 B18-008
Figure No. 15
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,719.8 feet
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
0
2.5
5
7.5
10
12.5
15
17.5
TOPSOIL: Lean CLAY, appears stiff, dark brown moist to
frozen, organics
Fat CLAY, appears stiff, brown, slightly moist
Poorly-Graded GRAVEL with Sand, appears dense, brown
and gray, slightly moist to saturated
Bottom of Test Pit
1.2
3.2
10.5
G
G
52
LEGEND LOG OF TEST PIT TP-8Atterberg Limits
Field Moisture content 206 East Griffin Drive
Bozeman, MontanaGroundwater Level
Grab/composite sample
Logged by:Ahren Hastings, PE
Excavated by:Earth Surgeons
Komatsu 170LCGNP = Granular and Nonplastic
Note: The stratification lines represent approximate
boundaries between soil types. Actual boundaries
may be gradual or transitional.
March 3, 2018 B18-008
Figure No. 16
SheetGRAPHICLOGSOIL DESCRIPTION
SURFACE:Native Grasses
SURFACE ELEVATION:4,722.9 feet
DEPTH (FT)GROUNDWATERSAMPLEDEPTH (FT)MOISTURE CONTENT
0 10 20 30 40 50
= MOISTURE CONTENT
1 of 1
Tested By: NJ Checked By:
10-29-2020
17
(no specification provided)
PL= LL= PI=
D90= D85= D60=
D50= D30= D15=
D10= Cu= Cc=
USCS= AASHTO=
*
Clayey SAND with Gravel
1.5"
1"
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#80
#100
#200
100.0
95.6
90.8
76.7
71.9
63.8
55.5
48.2
42.8
38.7
35.9
33.9
27.3
25 44 19
18.5261 16.0771 3.2770
1.0520 0.1020
SC A-2-7(1)
Report No. A-21982-206
Human Resource Development Council District IX, Inc.
206 East Griffin Drive
Bozeman, Montana
B18-008
Material Description
Atterberg Limits
Coefficients
Classification
Remarks
Location: B-1
Sample Number: A-21982 Depth: 25.0 - 26.4 ft Date:
Client:
Project:
Project No:Figure
SIEVE PERCENT SPEC.
*PASS?
SIZE FINER PERCENT (X=NO)PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.00010.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 9.2 27.0 8.3 12.7 15.5 27.36 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report
Tested By: NJ Checked By:
10-29-2020
18
(no specification provided)
PL= LL= PI=
D90= D85= D60=
D50= D30= D15=
D10= Cu= Cc=
USCS= AASHTO=
*
Elastic SILT with Sand
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#80
#100
#200
100.0
97.2
97.2
95.4
93.8
92.6
90.9
89.0
87.4
86.2
81.2
40 57 17
0.3242 0.1268
MH A-7-5(18)
Report No. A-21990-206
Human Resource Development Council District IX, Inc.
206 East Griffin Drive
Bozeman, Montana
B18-008
Material Description
Atterberg Limits
Coefficients
Classification
Remarks
Location: B-2
Sample Number: A-21990 Depth: 18.0 - 19.0 ft Date:
Client:
Project:
Project No:Figure
SIEVE PERCENT SPEC.
*PASS?
SIZE FINER PERCENT (X=NO)PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.00010.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 0.0 4.6 1.6 2.9 9.7 81.26 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report
Tested By: TF Checked By:
10-29-2020
19
(no specification provided)
PL= LL= PI=
D90= D85= D60=
D50= D30= D15=
D10= Cu= Cc=
USCS= AASHTO=
*
Clayey SAND with Gravel
1"
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#80
#100
#200
100.0
94.7
89.8
84.5
75.4
66.9
60.2
54.5
49.6
45.7
43.2
35.5
23 39 16
12.8573 9.7677 0.8269
0.2610
SC A-6(1)
Report No. A-22004-206
Human Resource Development Council District IX, Inc.
206 East Griffin Drive
Bozeman, Montana
B18-008
Material Description
Atterberg Limits
Coefficients
Classification
Remarks
Location: B-3
Sample Number: A-22004 Depth: 30.0 - 31.4 ft Date:
Client:
Project:
Project No:Figure
SIEVE PERCENT SPEC.
*PASS?
SIZE FINER PERCENT (X=NO)PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.00010.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 5.3 19.3 8.5 12.4 19.0 35.56 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report
Tested By: WJC Checked By:
10-29-2020
20
(no specification provided)
PL= LL= PI=
D90= D85= D60=
D50= D30= D15=
D10= Cu= Cc=
USCS= AASHTO=
*
Sandy Lean CLAY
1"
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#80
#100
#200
100.0
95.1
92.9
91.4
90.9
89.7
87.7
84.1
79.5
75.5
72.4
59.9
21 35 14
2.3849 0.4860 0.0754
CL A-6(6)
Report No. A-22006COMP-206
Human Resource Development Council District IX, Inc.
206 East Griffin Drive
Bozeman, Montana
B18-008
Material Description
Atterberg Limits
Coefficients
Classification
Remarks
Location: B-4/B-5
Sample Number: A-22006 COMP Depth: 2.5 - 4.0 ft Date:
Client:
Project:
Project No:Figure
SIEVE PERCENT SPEC.
*PASS?
SIZE FINER PERCENT (X=NO)PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.00010.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 4.9 4.2 1.2 5.6 24.2 59.96 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report
Tested By: TF Checked By:
10-29-2020
21
(no specification provided)
PL= LL= PI=
D90= D85= D60=
D50= D30= D15=
D10= Cu= Cc=
USCS= AASHTO=
*
Clayey GRAVEL with Sand
3"
1.5"
1"
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#80
#100
#200
100.0
96.6
89.5
80.3
66.0
59.3
48.3
42.4
38.0
34.1
31.3
29.4
28.3
24.6
18 30 12
25.9433 21.8360 9.8760
5.4640 0.1991
GC A-2-6(0)
Report No. A-22016-206
Human Resource Development Council District IX, Inc.
206 East Griffin Drive
Bozeman, Montana
B18-008
Material Description
Atterberg Limits
Coefficients
Classification
Remarks
Location: B-5
Sample Number: A-22016 Depth: 5.0 - 10.0 ft Date:
Client:
Project:
Project No:Figure
SIEVE PERCENT SPEC.
*PASS?
SIZE FINER PERCENT (X=NO)PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.00010.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 19.7 32.0 5.9 8.3 9.5 24.66 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report
Tested By: WJC Checked By:
10-29-2020
22
(no specification provided)
PL= LL= PI=
D90= D85= D60=
D50= D30= D15=
D10= Cu= Cc=
USCS= AASHTO=
*
Sandy Lean CLAY
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#80
#100
#200
100.0
98.0
94.7
88.8
85.0
80.2
75.6
72.6
70.7
68.6
59.2
22 45 23
5.7368 1.9911 0.0792
CL A-7-6(11)
Report No. A-22021COMP-206
Human Resource Development Council District IX, Inc.
206 East Griffin Drive
Bozeman, Montana
B18-008
Material Description
Atterberg Limits
Coefficients
Classification
Remarks
Location: B-6/B-7
Sample Number: A-22021 COMP Depth: 2.5 - 4.0 ft Date:
Client:
Project:
Project No:Figure
SIEVE PERCENT SPEC.
*PASS?
SIZE FINER PERCENT (X=NO)PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.00010.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 0.0 11.2 3.8 9.4 16.4 59.26 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report
Tested By: MS Checked By:
23
(no specification provided)
PL= LL= PI=
D90= D85= D60=
D50= D30= D15=
D10= Cu= Cc=
USCS= AASHTO=
*
Clayey GRAVEL with Sand
1.5"
1"
3/4"
1/2"
3/8"
#4
#10
#20
#40
#60
#80
#100
#200
100.0
95.7
84.6
73.9
69.4
60.1
51.0
44.2
38.4
33.7
30.6
28.6
22.5
21.7440 19.2472 4.7077
1.7829 0.1699
GC
Report No. A-17165-206
Date: 3-14-2018
Human Resource Development Council District IX, Inc.
206 East Griffin Drive
Bozeman, Montana
B18-008
Material Description
Atterberg Limits
Coefficients
Classification
Remarks
Location: TP-7
Sample Number: A-17165 Depth: 6.0 ft Date:
Client:
Project:
Project No:Figure
SIEVE PERCENT SPEC.
*PASS?
SIZE FINER PERCENT (X=NO)PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.00010.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 15.4 24.5 9.1 12.6 15.9 22.56 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200Particle Size Distribution Report
Tested By: MS Checked By:
LIQUID AND PLASTIC LIMITS TEST REPORT
PLASTICITY INDEX0
10
20
30
40
50
60
LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
C L o r O L
C H o r O H
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
47
WATER CONTENT42.2
42.6
43
43.4
43.8
44.2
44.6
45
45.4
45.8
46.2
NUMBER OF BLOWS
5 6 7 8 9 10 20 25 30 40
MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
Project No. Client:Remarks:
Project:
Location: B-1
Sample Number: A-21982 Depth: 25.0 - 26.4 ft
Figure
Clayey SAND with Gravel 44 25 19 42.8 27.3 SC
B18-008 Human Resource Development Council District IX, Inc.
24
Report No. A-21982-207
Date: 10-29-2020206 East Griffin Drive
Bozeman, Montana
Tested By: MS Checked By:
LIQUID AND PLASTIC LIMITS TEST REPORT
PLASTICITY INDEX0
10
20
30
40
50
60
LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
C L o r O L
C H o r O H
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
47
WATER CONTENT55.4
55.8
56.2
56.6
57
57.4
57.8
58.2
58.6
59
59.4
NUMBER OF BLOWS
5 6 7 8 9 10 20 25 30 40
MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
Project No. Client:Remarks:
Project:
Location: B-2
Sample Number: A-21990 Depth: 18.0 - 19.0 ft
Figure
Elastic SILT with Sand 57 40 17 90.9 81.2 MH
B18-008 Human Resource Development Council District IX, Inc.
25
Report No. A-21990-207
Date: 10-29-2020206 East Griffin Drive
Bozeman, Montana
Tested By: MS Checked By:
LIQUID AND PLASTIC LIMITS TEST REPORT
PLASTICITY INDEX0
10
20
30
40
50
60
LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
C L o r O L
C H o r O H
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
47
WATER CONTENT34
35
36
37
38
39
40
41
42
43
44
NUMBER OF BLOWS
5 6 7 8 9 10 20 25 30 40
MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
Project No. Client:Remarks:
Project:
Location: B-3
Sample Number: A-22004 Depth: 30.0 - 31.4 ft
Figure
Clayey SAND with Gravel 39 23 16 54.5 35.5 SC
B18-008 Human Resource Development Council District IX, Inc.
26
Report No. A-22004-207
Date: 10-29-2020206 East Griffin Drive
Bozeman, Montana
Tested By: MS Checked By:
LIQUID AND PLASTIC LIMITS TEST REPORT
PLASTICITY INDEX0
10
20
30
40
50
60
LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
C L o r O L
C H o r O H
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
47
WATER CONTENT32.4
32.8
33.2
33.6
34
34.4
34.8
35.2
35.6
36
36.4
NUMBER OF BLOWS
5 6 7 8 9 10 20 25 30 40
MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
Project No. Client:Remarks:
Project:
Location: B-4/B-5
Sample Number: A-22006 COMP Depth: 2.5 - 4.0 ft
Figure
Sandy Lean CLAY 35 21 14 84.1 59.9 CL
B18-008 Human Resource Development Council District IX, Inc.
27
Report No. A-22006COMP-207
Date: 10-30-2020206 East Griffin Drive
Bozeman, Montana
Tested By: MS Checked By:
LIQUID AND PLASTIC LIMITS TEST REPORT
PLASTICITY INDEX0
10
20
30
40
50
60
LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
C L o r O L
C H o r O H
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
47
WATER CONTENT28.6
28.8
29
29.2
29.4
29.6
29.8
30
30.2
30.4
30.6
NUMBER OF BLOWS
5 6 7 8 9 10 20 25 30 40
MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
Project No. Client:Remarks:
Project:
Location: B-5
Sample Number: A-22016 Depth: 5.0 - 10.0 ft
Figure
Clayey GRAVEL with Sand 30 18 12 34.1 24.6 GC
B18-008 Human Resource Development Council District IX, Inc.
28
Report No. A-22016-207
Date: 10-30-2020206 East Griffin Drive
Bozeman, Montana
Tested By: NJ Checked By:
LIQUID AND PLASTIC LIMITS TEST REPORT
PLASTICITY INDEX0
10
20
30
40
50
60
LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
C L o r O L
C H o r O H
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
47
WATER CONTENT43.8
44.2
44.6
45
45.4
45.8
46.2
46.6
47
47.4
47.8
NUMBER OF BLOWS
5 6 7 8 9 10 20 25 30 40
MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
Project No. Client:Remarks:
Project:
Location: B-6/B-7
Sample Number: A-22021 COMP Depth: 2.5 - 4.0 ft
Figure
Sandy Lean CLAY 45 22 23 75.6 59.2 CL
B18-008 Human Resource Development Council District IX, Inc.
29
Report No. A-22021COMP-207
Date: 10-30-2020206 East Griffin Drive
Bozeman, Montana
Tested By: MS Checked By:
LIQUID AND PLASTIC LIMITS TEST REPORT
PLASTICITY INDEX0
10
20
30
40
50
60
LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
C L o r O L
C H o r O H
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
47
WATER CONTENT46
47
48
49
50
51
52
53
54
55
56
NUMBER OF BLOWS
5 6 7 8 9 10 20 25 30 40
MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
Project No. Client:Remarks:
Project:
Location: TP-7
Sample Number: A-17163 Depth: 2.0 ft
Figure
Fat CLAY 51 28 23 CH
B18-008 Human Resource Development Council District IX, Inc.
30
Report No. A-17163-207
Date: 3-14-2018206 East Griffin Drive
Bozeman, Montana
Tested By: MS Checked By:
LIQUID AND PLASTIC LIMITS TEST REPORT
PLASTICITY INDEX0
10
20
30
40
50
60
LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
C L o r O L
C H o r O H
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
47
WATER CONTENT47
48
49
50
51
52
53
54
55
56
57
NUMBER OF BLOWS
5 6 7 8 9 10 20 25 30 40
MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
Project No. Client:Remarks:
Project:
Location: TP-8
Sample Number: A-17166 Depth: 2.0 ft
Figure
Fat CLAY 52 27 25 CH
B18-008 Human Resource Development Council District IX, Inc.
31
Report No. A-17166-207
Date: 3-14-2018206 East Griffin Drive
Bozeman, Montana
QUALITY CHECK:
DESIGNED BY:
DRAWN BY:
CAD NO.
JOB NO.
DATE:
FOUNDATION SCHEMATIC
COMMUNITY FIRST GRIFFIN PLACE
BOZEMAN, MONTANA
SCHEMATIC FOOTING & SLAB FOUNDATION DETAIL
SEJ
KLS
2020.11.11
B18-008
FIGURE
32Engineering
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