HomeMy WebLinkAbout6.0_Soils Investigation Report 1091 Stoneridge Drive • Bozeman, Montana • Phone (406) 587-1115 • Fax (406) 587-9768
www.chengineers.com • E-Mail: info@chengineers.com
April 9, 2021
Summit & Sky, LLC
Attn: Jennifer Salazar
E-mail: jsalazar@tksent.org
RE: Soils Investigation Report – 6590 Davis Lane; Gallatin County, Montana (210280.1).
Dear Jennifer,
Per your request, C&H Engineering and Surveying Inc., (C&H Engineering) has conducted a
subsurface soils investigation for the above referenced property. The subject property is located
in the Southwest Quarter of Section 35, Township 1 South, Range 5 East in Gallatin County,
Montana and consists of 8.56 acres. The scope of services was to conduct a subsurface soils
investigation and provide a soils investigation report. The report documents the site conditions,
soil properties, and provides foundation design and general earthwork recommendations.
Proposed Construction
This report was completed prior to purchase of the subject property and detailed plans regarding
development were not available. For purposes of this report we have assumed that either single-
family or multi-family residential structures (up to three stories in height) will be constructed on
the site.
It has been assumed that the foundation footings will not be subjected to unusual loading
conditions such as eccentric loads. If any of the foundation footings will be eccentrically loaded
please contact this office so we can appropriately revise our allowable bearing capacity and
settlement estimates.
Subsurface Soil and Conditions
On March 26, 2021 a member of the staff of C&H Engineering visited the site to conduct a
subsurface soils investigation. The subsurface soils investigation consisted of examining eleven
exploratory test pit excavations. The exploratory test pits were excavated with a John Deere
Backhoe provided by Val Mencas Excavation, LLC. The soil profiles revealed by the
exploratory excavations were logged and visually classified according to ASTM D 2488, which
utilizes the nomenclature of the Unified Soil Classification System (USCS).
The following paragraphs briefly summarize the subsurface soils and conditions observed in the
exploratory test pit excavated for the field investigation. The soil horizons are described as they
were encountered in the test pit excavations, starting with the horizon nearest the surface and
proceeding with each additional horizon encountered with depth. Please refer to the attached test
SOILS INVESTIGATION REPORT
#210280.1 – 6590 DAVIS LANE; BOZEMAN, MONTANA 2
pit logs for more detailed information.
The first soil horizon encountered in each of the exploratory excavations was an Organic Soil of
Low Plasticity (OL), which was present to a depths varying from 1.5 feet below grounds surface
(bgs) to 2.3 feet bgs. This material was black in color, moist, and very soft. Organic soils are
highly compressible and are not suitable for foundation support. This material must also be
removed from beneath all interior and exterior slabs as well as beneath all asphalt paving
improvements. This material may be stockpiled onsite and used for final site grading purposes.
The second soil horizon encountered in each exploratory excavation was a Lean Clay with Sand
(CL), which was encountered to a depths varying from 4.1 feet bgs tp 8.2 feet bgs. This material
was light brown to gray in color, moist to very moist, and very soft. Atterberg limits testing on
this material yielded a liquid limit ranging from 37 to 41 and a plasticity index ranging from 17
to 22. Soils with a liquid limit less than 50 and plasticity index less than 25 are not considered to
be expansive. Although not expansive, this material is highly moisture sensitive and highly
compressible and because of this, it is not suitable for foundation support. It should be noted that
seepage was encountered in most of the test pits at the interface of this material and the overlying
organic soil.
Underlying the Lean Clay with Sand in TP-6 and TP-7 was a Gravelly Lean Clay with Sand
(CL). This material contained clay bound gravels and sand and was in a relatively loose
condition. This material was grayish brown in color and consisted of approximately 35 percent
rounded and subrounded gravels and cobbles, approximately 15 percent coarse to fine grained
sand and approximately 50 percent Silt/Clay fines.
The final soil horizon encountered in each exploratory excavation was a Poorly Graded Gravel
with Sand and Cobbles (GP), known locally as “pit-run” gravel. This material was bluish gray to
brown in color and consisted of approximately 50 percent rounded and subrounded gravels and
cobbles, approximately 40 percent coarse to fine grained sand and approximately 10 percent
Silt/Clay fines. Groundwater was encountered within this interval in each exploratory
excavation. This material was found to be in a medium dense condition and is the target bearing
material for any structure constructed on the subject property. This is also the general target
bearing material for most construction in the general Bozeman area.
Based on the subsurface investigation, it is recommended that all foundation footings bear on the
Poorly Graded Gravel with Sand and Cobbles or on properly placed and compacted structural fill
overlying this material.
It should be noted that a Gravel Layer was encountered in TP-6 & TP-7 that contains a
significant amount of clay, and this is not the target bearing material. It appears there is a
corridor between these test pits where the depth to the Poorly Graded Gravel with Sand and
Cobbles is deeper than in the other areas of the subject property.
Groundwater
Seepage and/or groundwater was encountered within each of the eleven exploratory excavations.
SOILS INVESTIGATION REPORT
#210280.1 – 6590 DAVIS LANE; BOZEMAN, MONTANA 3
The depth to groundwater varied from 5.9 feet bgs to 9.2 feet bgs. Generally speaking, the
groundwater levels were higher near the northern end of the subject property, except for the
triangular area in the northeast corner of the subject property, where groundwater levels were
found to be more similar to those at the southern end of the property.
Evidence of seasonally high groundwater, such as high moisture content, gleyed soils, and
mottling was observed in each of the exploratory excavations. Based on our observations, it
appears the seasonally high groundwater elevation is rising up to near 2.5 feet bgs in the
northwest corner and along much of the northern end of the property and rising up to near 3.5
feet at the southern end of the subject property. Groundwater levels are likely the highest in the
wet area adjacent to the creek (north center area), but we could not excavate a test pit in this area
due to the very soft ground conditions that would not allow the backhoe to gain access without
getting stuck in the very soft organic soils in this area.
Also, seepage was encountered in nearly each of the excavations at the interface of the Organic
Soil and underlying Lean Clay with Sand. This water is from snowmelt and precipitation events
that is migrating down through the Organic Soil and then collecting above the Lean Clay with
Sand due to its low permeability and high insitu water content. This was most pronounced along
the northern end of the subject property.
Please note that our subsurface investigation is not a detailed groundwater study, and
groundwater conditions may change dramatically due to conditions that are out of our control.
Our assessment of the groundwater conditions is based on the conditions observed within the
exploratory test pits on the day of the excavation, our general experience in the project area, and
any available literature regarding groundwater conditions in the vicinity of the subject property.
If more detailed knowledge of the seasonally high groundwater elevation across the subject
property is desired, it is recommended that groundwater monitoring wells be installed and
checked weekly from the early spring to late summer months in order to determine the peak
seasonally high groundwater elevation.
Foundation Recommendations
Based on the subsurface soils encountered in the exploratory excavation, slab-on-grade with
stem wall foundations are recommended. Crawl space and/or basement foundations are not
recommended due to the potential for seasonally high groundwater. Please find the following as
general recommendations for all foundation elements:
In order to keep the footing out of the active frost zone it is recommended that the bottom
of all footing elevations be a minimum of 48 inches below finished grade.
It is recommended that typical strip footings for this structure have a minimum width of
16 inches and column footings should have a minimum width of 24 inches, provided the
soils allowable bearing capacity is not exceeded.
SOILS INVESTIGATION REPORT
#210280.1 – 6590 DAVIS LANE; BOZEMAN, MONTANA 4
Allowable Bearing Capacity & Settlement
The bearing capacity of a soil is defined as the ultimate pressure per unit area by the foundation
that can be supported by the soil in excess of the pressure caused by the surrounding soil at the
footing level. Bearing capacity is determined by the physical and chemical properties of the soil
located beneath the proposed structures footings.
Based on the subsurface investigation, it is recommended that all foundation footings bear on the
Poorly Graded Gravel with Sand and Cobbles or on properly placed and compacted structural fill
overlying this material. For foundation footings bearing on the Poorly Graded Gravel with Sand,
it is recommended that an allowable bearing capacity of 2,500 pounds per square foot be used to
design the footings.
Settlement and differential settlement were estimated using conservative soil parameters and the
assumption that the foundation subgrade will be prepared in accordance with the
recommendations made in this report. Based on conservative soil parameter estimates, the
bearing capacity recommended, and the assumption that all recommendations made in this report
will be properly implemented, it is expected that total and differential settlement will be ½-inch
or less. Structures of the type proposed can generally tolerate movements of this magnitude,
however, this movement should be checked by a structural engineer to determine if it is
acceptable.
Lateral Pressures
Lateral pressures imposed upon foundation and retaining walls due to wind, seismic forces, and
earth pressures may be resisted by the development of passive earth pressures and/or frictional
resistance between the base of the footings and the supporting soils. If a foundation or retaining
wall is restrained from moving, the lateral earth pressure exerted on the wall is called the at-rest
earth pressure. If a foundation or retaining wall is allowed to tilt away from the retained soil, the
lateral earth pressure exerted on the wall is called the active earth pressure. Passive earth
pressure is the resistance pressure the foundation or retaining wall develops due to the wall being
pushed laterally into the earth on the opposite side of the retained soil. Each of these pressures is
proportional to the distance below the earth surface, the unit weight of the soil, and the shear
strength properties of the soil.
Subsurface walls that are restrained from moving at the top are recommended to be designed for
an equivalent fluid pressure of 60 pounds per cubic foot (pcf) (at-rest pressure); the equivalent
fluid pressure is the product of the retained soils unit weight and its coefficient of active or at-
rest earth pressure. Any subsurface walls that are allowed to move away from the restrained soil,
such as cantilevered retaining walls, are recommended to be designed for an equivalent fluid
pressure of 30 pcf (active pressure). For passive pressures, an equivalent fluid pressure of 200
pcf is recommended, and the coefficient of friction between the cast-in-place concrete and the
Lean Clay with Sand is estimated to be 0.3.
These recommended values were calculated assuming a near horizontal backfill and that a well-
draining granular material will be imported for use as foundation wall backfill. It is also assumed
SOILS INVESTIGATION REPORT
#210280.1 – 6590 DAVIS LANE; BOZEMAN, MONTANA 5
that the backfill will be placed and compacted as recommended in this report.
Also, please note that these design pressures do not include a factor of safety and are for static
conditions, they do not account for additional forces that may be induced by seismic loading.
Subgrade Preparation and Structural Fill
Please note that dewatering will likely be required to be able to properly excavate down to the
target bearing material and then begin to properly place and compact any required structural fill.
A dewatering plan is not included in the scope of services and is not part of this report.
In general, the excavation for the foundation must be level and uniform and continue down to the
Poorly Graded Gravel with Sand and Cobbles or to the desired bottom of footing elevation,
whichever is deeper. Due to the very soft soil encountered above the target bearing material, it is
recommended that the entire building footprint(s) be taken down to the Poorly Graded Gravel
with Sand and Cobbles. If any soft spots, undocumented fill or boulders are encountered, they
will need to be removed and backfilled with structural fill. The excavation width must extend a
minimum of one footing width from the outer edges of the footings or to a distance equal to ½
the height of the required structural fill, whichever is greater. For example, if 6 feet of structural
fill is required, the excavation must extend out from the footing a minimum distance of 3 feet.
Once the excavation is completed, the native subgrade shall be proof rolled with a large
compactor to an unyielding condition. Any areas that are found to be pumping or rutting shall be
sub-excavated and replaced with structural fill.
Structural fill is defined as all fill that will ultimately be subjected to structural loadings, such as
those imposed by footings, floor slabs, pavements, etc. Structural fill will need to be imported for
this site. Imported structural fill is recommended to be a well graded gravel with sand that
contains less than 15 percent of material that will pass a No. 200 sieve and that has a maximum
particle size of 3 inches. Also, the fraction of material passing the No. 40 sieve shall have a
liquid limit not exceeding 25 and a plasticity index not exceeding 6. The gravel and sand
particles also need to be made up of durable rock materials that will not degrade when
compacted; no shale or mudstone fragments should be present.
Structural fill must be placed in lifts no greater than 12 inches (uncompacted thickness) and be
uniformly compacted to a minimum of 97 percent of its maximum dry density, as determined by
ASTM D698. Typically, the structural fill must be moisture conditioned to within + 2 percent of
the materials optimum moisture content to achieve the required density. It is recommended that
the structural fill be compacted with a large vibrating smooth drum roller. Please note that if a
moisture-density relationship test (commonly referred to as a proctor) needs to be performed for
a proposed structural fill material to determine its maximum dry density and optimum moisture
content in accordance with ASTM D698, a sample of the material must be delivered to this
office a minimum of three full working days prior to beginning placement of the structural fill.
At no time should surface water runoff be allowed to flow into and accumulate within the
excavation for the foundation elements. If necessary, a swale or berm should be temporarily
SOILS INVESTIGATION REPORT
#210280.1 – 6590 DAVIS LANE; BOZEMAN, MONTANA 6
constructed to reroute all surface water runoff away from the excavation. Excavation should not
proceed during large precipitation events.
If any of the foundation footings are found to be located on a test pit, the area will need to be
excavated down to the full depth of the test pit and structural fill be placed and compacted in
carefully controlled lifts (as described in this report) to bring the area back up to the desired
grade.
Foundation Wall Backfill
Approved backfill material should be placed and compacted between the foundation wall and the
edge of the excavation. The native soils encountered during the field investigation were found to
be very moist and will not be suitable for reuse as foundation wall backfill. Foundation wall
backfill will need to be imported for this site. Imported foundation wall backfill is recommended
to be a well-draining granular material. Structural fill is recommended as foundation wall
backfill in all areas that will support concrete slabs-on-grade or other paving improvements. The
foundation wall backfill shall be placed in uniform lifts and be compacted to a minimum of 95
percent of the material’s maximum dry density, as determined by ASTM D698.
The foundation wall backfill will need to be compacted with either walk behind compaction
equipment or hand operated compaction equipment in order to avoid damaging the foundation
walls. If walk behind compaction equipment is used, lifts should not exceed 8-inches (loose
thickness) and if hand operated compaction equipment is used lifts should not exceed 4-inches
(loose thickness).
Interior Slabs-on-Grade
Due to the very soft soils encountered in the exploratory excavations, it is recommended that the
entire building footprint be taken down to the Poorly Graded Gravel with Sand and Cobbles.
Structural fill can then be placed and compacted to 6 inches below the bottom of slab elevation.
For all interior concrete slabs-on-grade, preventative measures must be taken to stop moisture
from migrating upwards through the slab. Moisture that migrates upwards through the concrete
slab can damage floor coverings such as carpet, hardwood and vinyl, in addition to causing
musty odors and mildew growth. Moisture barriers will need to be installed to prevent water
vapor migration and capillary rise through the concrete slab.
In order to prevent capillary rise through the concrete slab-on-grade it is recommended that 6
inches of ¾-inch washed rock (containing less than 10 percent fines) be placed and compacted
once the excavation for the slab is complete. The washed rock has large pore spaces between
soil particles and will act as a capillary break, preventing groundwater from migrating upwards
towards the bottom of the slab.
In order to prevent the upward migration of water vapor through the slab, it is recommended that
a 15-mil extruded polyolefin plastic that complies with ASTM E1745 (such as a Stego Wrap 15-
mil Vapor Barrier) be installed. The vapor barrier should be pulled up at the sides and secured to
the foundation wall or footing. Care must be taken during and after the installation of the vapor
SOILS INVESTIGATION REPORT
#210280.1 – 6590 DAVIS LANE; BOZEMAN, MONTANA 7
barrier to avoid puncturing the material, and all joints are to be sealed per the manufacture’s
recommendations.
Once the excavation for the interior slab-on-grade is completed as described in the first
paragraph of this section, and the ¾ inch washed rock and moisture barriers have been properly
installed, it will be acceptable to form and cast the steel reinforced concrete slab. It is
recommended that interior concrete slabs-on-grade have a minimum thickness of 4 inches, unless
the slab will be supporting vehicles, then the recommended minimum thickness is 6 inches,
unless the slab reinforcement is designed by a licensed structural engineer.
Exterior Slabs-on-Grade
For exterior areas to be paved with concrete slabs, it is recommended that, at a minimum, the
Organic Soil be Removed. The native subgrade then needs to be compacted to a minimum of 95
percent of its maximum dry density, as determined by ASTM D698. Then for non-vehicular
traffic areas, a minimum of 12 inches of ¾-inch minus rock needs to be placed, and 4 inches of
4000 pounds per square inch (psi) concrete placed over the ¾-inch minus rock. For areas with
vehicular traffic, a minimum of 9 inches of ¾-inch minus rock should be placed, followed by 12
inches of 4000 psi concrete.
Exterior slabs that will be located adjacent to the foundation walls need to slope away from the
structure at a minimum grade of 2 percent and should not be physically connected to the
foundation walls. If they are connected, any movement of the exterior slab will be transmitted to
the foundation wall, which may result in damage to the structure.
Asphalt Paving Improvements
For areas to be paved with asphalt, it is recommended that, as a minimum, the Organic Soil be
removed. The native subgrade then needs to be compacted at ± 2 percent of its optimum
moisture content to 95 percent of its maximum dry density, as determined by ASTM D698.
Following compaction of the native subgrade, a layer of woven geotextile (such as a Mirafi
500X) shall be installed followed by a layer of Tensar TX5 Triaxial Geogrid placed directly over
the woven geotextile. Next a 18-inch thick layer of compacted 3-inch minus gravel needs to be
placed and compacted, followed by a 6-inch layer of compacted 1-inch minus road mix. Both
gravel courses must be compacted at ± 2 percent of their optimum moisture content to 95 percent
of their maximum dry density, as determined by ASTM D698. A 3-inch-thick layer of asphalt
pavement can then be placed and compacted over this cross-section.
Site Grading
Surface water should not be allowed to accumulate and infiltrate the soil near the foundation.
Proper site grading will ensure surface water runoff is directed away from the foundation. Please
find the following as general site grading recommendations:
Finished grade must slope away from the building a minimum of 5 percent within the
first 10 feet, in order to quickly drain ground surface and roof runoff away from the
SOILS INVESTIGATION REPORT
#210280.1 – 6590 DAVIS LANE; BOZEMAN, MONTANA 8
foundation walls. Please note that in order to maintain this slope; it is imperative that any
backfill placed against the foundation walls be compacted properly. If the backfill is not
compacted properly, it will settle and positive drainage away from the structure will not
be maintained.
Permanent sprinkler heads for lawn care should be located a sufficient distance from the
structure to prevent water from draining toward the foundation or saturating the soils
adjacent to the foundation.
Rain gutter down spouts are to be placed in such a manner that surface water runoff
drains away from the structure.
All roads, walkways, and architectural land features must properly drain away from all
structures. Special attention should be made during the design of these features to not
create any drainage obstructions that may direct water towards or trap water near the
foundation.
Construction Administration
The foundation is a vital element of a structure; it transfers all of the structure’s dead and live
loads to the native soil. It is imperative that the recommendations made in this report are
properly adhered to. A representative from C&H Engineering should observe the construction of
any foundation or drainage elements recommended in this report. The recommendations made in
this report are contingent upon our involvement. If the soils encountered during the excavation
differ than those described in this report or any unusual conditions are encountered, our office
should be contacted immediately to examine the conditions, re-evaluate our recommendations
and provide a written response.
If construction and site grading take place during cold weather, it is recommended that approved
winter construction practices be observed. All snow and ice shall be removed from cut and fill
areas prior to site grading taking place. No fill should be placed on soils that are frozen or
contain frozen material. No frozen soils can be used as fill under any circumstances.
Additionally, Concrete should not be placed on frozen soils and should meet the temperature
requirements of ASTM C 94. Any concrete placed during cold weather conditions shall be
protected from freezing until the necessary compressive strength has been attained. Once the
footings are placed, frost shall not be permitted to extend below the foundation footings, as this
could heave and crack the foundation footings and/or foundation walls.
It is the responsibility of the contractor to provide a safe working environment with regards to
excavations on the site. All excavations should be sloped or shored in the interest of safety and
in accordance with local and federal regulations, including the excavation and trench safety
standards provided by the Occupational Safety and Health Administration (OSHA).
Report Limitations
The recommendations made in this report are based on limited information obtained from the
GB1-1
MC = 27%LL = 41
PL = 19PI = 22Fines = 88%
OL
CL
GP
1.8
6.0
6.8
0 TO 1.75 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low
plasticity; no diltancy; very soft; seepage observed at interface of organic soil
and underlying lean clay with sand.
1.75 TO 6 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist
to very moist; medium plasticity; no diltancy; very soft; gleyed starting at a
depth of approximately 3.0 feet.
6 TO 6.8 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES;(GP); blueish to gray; saturated; non plastic plasticity; medium dense.
Bottom of test pit at 6.8 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 6.80 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP1
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJTESTS
U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
OL
CL
GP
1.6
5.8
6.7
0 TO 1.58 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low plasticity; no
diltancy; very soft; seepage observed at interface of organic soil and underlying lean clay
with sand.
1.58 TO 5.8 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist to very moist;
medium plasticity; no diltancy; very soft; gleyed starting at a depth of approximately 2.7 feet.
5.8 TO 6.7 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); blueishto gray; saturated; non plastic plasticity; medium dense.
Bottom of test pit at 6.7 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 6.70 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP2
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
GB
3-1
MC = 25%LL = 37
PL = 18PI = 19
Fines = 81%
OL
CL
GP
1.5
4.8
5.9
0 TO 1.5 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low
plasticity; no diltancy; very soft; seepage observed at interface of organic soil
and underlying lean clay with sand.
1.5 TO 4.8 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist
to very moist; medium plasticity; no diltancy; very soft; gleyed starting at adepth of approximately 3.0 feet.
4.8 TO 5.9 FEET: POORLY GRADED GRAVEL WITH SAND AND
COBBLES; (GP); blueish to gray; saturated; non plastic plasticity; medium
dense.
Bottom of test pit at 5.9 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 5.90 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP3
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJTESTS
U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
OL
CL
GP
2.0
5.1
5.9
0 TO 2 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low plasticity; no diltancy;
very soft; seepage observed at interface of organic soil and underlying lean clay with sand.
2 TO 5.1 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist to very moist;
medium plasticity; no diltancy; very soft; gleyed starting at a depth of approximately 3.0 feet.
5.1 TO 5.9 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); blueish
to gray; saturated; non plastic plasticity; medium dense.
Bottom of test pit at 5.9 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 5.90 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP4
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
OL
CL
GP
1.5
5.2
6.9
0 TO 1.5 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low plasticity; no diltancy;
very soft; seepage observed at interface of organic soil and underlying lean clay with sand.
1.5 TO 5.2 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist to very moist;
medium plasticity; no diltancy; very soft; gleyed starting at a depth of approximately 3.0 feet,seepage at 4.0 feet.
5.2 TO 6.9 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); blueish
to gray; saturated; non plastic plasticity; medium dense.
Bottom of test pit at 6.9 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 6.90 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP5
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
OL
CL
CL
GP
2.3
4.1
8.7
9.0
0 TO 2.3 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low plasticity; no diltancy;
very soft; seepage observed at interface of organic soil and underlying lean clay with sand.
2.3 TO 4.1 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist to very moist;
medium plasticity; no diltancy; very soft; gleyed starting at a depth of approximately 4.0 feet.
4.1 TO 8.7 FEET: GRAVELLY LEAN CLAY WITH SAND; (CL); grayish to brown; moist to
very moist; low plasticity; loose.
8.7 TO 9 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); blueish togray; saturated; non plastic plasticity; medium dense.
Bottom of test pit at 9.0 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 8.70 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0
7.5 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP6
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
OL
CL
CL
GP
2.0
5.5
9.2
9.5
0 TO 2 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low plasticity; no diltancy;
very soft; seepage observed at interface of organic soil and underlying lean clay with sand.
2 TO 5.5 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist to very moist;
medium plasticity; no diltancy; very soft; gleyed starting at a depth of approximately 4.0 feet.
5.5 TO 9.2 FEET: GRAVELLY LEAN CLAY WITH SAND; (CL); grayish to brown; moist to
very moist; low plasticity; loose.
9.2 TO 9.5 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); blueish
to gray; saturated; non plastic plasticity; medium dense.
Bottom of test pit at 9.5 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 9.20 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0
7.5 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP7
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
OL
CL
GP
2.1
5.1
6.3
0 TO 2.1 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low plasticity; no diltancy;
very soft; seepage observed at interface of organic soil and underlying lean clay with sand.
2.1 TO 5.1 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist to very moist;
medium plasticity; no diltancy; very soft; gleyed starting at a depth of approximately 4.5 feet.
5.1 TO 6.3 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); blueish
to gray; saturated; non plastic plasticity; medium dense.
Bottom of test pit at 6.3 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 6.30 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP8
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
GB9-1
MC = 26%LL = 39
PL = 22PI = 17Fines = 81%
OL
CL
GP
2.0
4.6
6.7
0 TO 2 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low
plasticity; no diltancy; very soft; seepage observed at interface of organic soil
and underlying lean clay with sand.
2 TO 4.6 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist to
very moist; medium plasticity; no diltancy; very soft; gleyed starting at a depth
of approximately 3.5 feet.
4.6 TO 6.7 FEET: POORLY GRADED GRAVEL WITH SAND AND
COBBLES; (GP); blueish to gray; saturated; non plastic plasticity; medium
dense.
Bottom of test pit at 6.7 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 6.70 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP9
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJTESTS
U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
OL
CL
GP
1.7
6.9
9.0
0 TO 1.67 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low plasticity; no
diltancy; very soft.
1.67 TO 6.9 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist to very moist;
medium plasticity; no diltancy; very soft; gleyed starting at a depth of approximately 4.0 feet,
seepage at 4.0 feet.
6.9 TO 9 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); blueish to
gray; saturated; non plastic plasticity; medium dense.
Bottom of test pit at 9.0 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 9.00 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0
7.5 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP10
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION
OL
CL
GP
2.2
8.2
9.2
0 TO 2.2 FEET: ORGANIC SOIL; (OL); black; moist to very moist; low plasticity; no diltancy;
very soft.
2.2 TO 8.2 FEET: LEAN CLAY WITH SAND; (CL); light brown to gray; moist to very moist;
medium plasticity; no diltancy; very soft; gleyed starting at a depth of approximately 4.1 feet,
seepage at 4.1 feet.
8.2 TO 9.2 FEET: POORLY GRADED GRAVEL WITH SAND AND COBBLES; (GP); blueishto gray; saturated; non plastic plasticity; medium dense.
Bottom of test pit at 9.2 feet.
NOTES
GROUND ELEVATION
LOGGED BY Michael J. Welch, P.E.
EXCAVATION METHOD Deere 410 C Backhoe
EXCAVATION CONTRACTOR Val Mencas Excavation, LLC GROUND WATER LEVELS:
DATE STARTED 3/26/21 COMPLETED 3/26/21
AT TIME OF EXCAVATION 9.20 ft
AFTER EXCAVATION ---
AT END OF EXCAVATION ---DEPTH(ft)0.0
2.5
5.0
7.5 SAMPLE TYPENUMBERPAGE 1 OF 1
TEST PIT NUMBER TP11
PROJECT NUMBER 210280.1
CLIENT Summit & Sky, LLC
PROJECT LOCATION 6590 Davis Lane, Bozeman, MT
PROJECT NAME Soils Investigation
GENERAL BH / TP / WELL - GINT STD US.GDT - 4/9/21 11:44 - G:\C&H\21\210280\GEOTECHNICAL REPORT\TEST PIT LOGS (210280.1).GPJU.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION