PZ - Geotech Eval Peterson Property ALLWEaT MATERIALS OTESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
February 23, 2022
Shawn Brownlee
Trilogy Development
9839 West Cable Car Street, Suite 101
Boise, Idaho 83709
Atn(@triIoqyidaho.com
RE: Geotechnical Evaluation
Peterman Property Development
Meridian, Idaho
ALLWEST Project No. 521-113G
Mr. Brownlee:
ALLWEST has completed the authorized geotechnical evaluation for the proposed
Peterman Property Development to be located at 5215 West Chinden Boulevard in
Meridian, Idaho. The purpose of this evaluation was to characterize subsurface soil
conditions at the site and provide geotechnical recommendations to assist planning, design,
and construction of the proposed development. Based on our evaluation, the site is suitable
for the planned development.The attached report presents the results of ourfield evaluation,
laboratory testing, and our recommendations.
We appreciate the opportunity to be of service to Trilogy Development. If you have any
questions or need additional information, please contact us at(208) 895-7898.
Sincerely,
ALLWEST
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Adrian Mascorro, P.E. >1kA
Area Manager
255 N. Linder Rd., Suite#100, Meridian, ID 83642
Phone: 208.895.7898 • Fax: 208.898.3959
Hayden, ID• Lewiston, ID• Meridian, ID•Spokane Valley,WA• Missoula, MT
www.allwesttesting.com
GEOTECHNICAL EVALUATION
PETERMAN PROPERTY DEVELOPMENT
MERIDIAN, IDAHO
ALLWEST PROJECT NO. 521 -113G
February 23, 2022
Prepared for:
Trilogy Development
9839 West Cable Car Street, Suite 101
Nampa, Idaho 83709
Prepared By:
ALLWEST
255 North Linder Road, Suite 100
Meridian, Idaho 83642
A LWE T
WWW.ALLWESTTESTING.COM
TABLE OF CONTENTS
ALLWEST Project No. 521-113G
Peterman Property Development
Meridian, Idaho
Page
1.0 SCOPE OF SERVICES ........................................................................................2
2.0 PROJECT UNDERSTANDING.............................................................................2
3.0 FIELD EVALUATION PROCEDURES.................................................................3
4.0 SITE CONDITIONS ..............................................................................................3
4.1 General Geologic Conditions............................................................................. 3
4.2 General Soil Conditions..................................................................................... 3
5.0 EXPLORATION AND SAMPLING .......................................................................3
5.1 Subsurface Soil Conditions ...............................................................................4
5.2 Subsurface Water..............................................................................................4
6.0 LABORATORY TESTING ....................................................................................4
7.0 CONCLUSIONS AND RECOMMENDATIONS ....................................................5
7.1 Grading and Drainage....................................................................................... 5
7.2 Site Preparation................................................................................................. 5
7.3 Subgrade Stabilization ...................................................................................... 6
7.4 Excavation......................................................................................................... 7
7.5 Materials............................................................................................................ 7
7.6 Fill Placement and Compaction......................................................................... 8
7.7 Utility Trenches.................................................................................................. 8
7.8 Wet Weather Construction ................................................................................ 9
7.9 Cold Weather Construction ............................................................................... 9
7.10 Stormwater Disposal ..................................................................................... 10
7.11 Asphalt Pavements ....................................................................................... 10
8.0 ADDITIONAL RECOMMENDED SERVICES..................................................... 11
9.0 EVALUATION LIMITATIONS............................................................................. 12
Appendix A— Site Vicinity Map, Exploration Location Plan
Appendix B —Test Pit Logs, Unified Soil Classification System
Appendix C— Laboratory Test Results
GEOTECHNICAL I ENVIRONMENTAL
ALLWESTMATERIALS TESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
Geotechnical Evaluation
Peterman Property Development
Meridian, Idaho
ALLWEST has completed the geotechnical evaluation for the proposed Peterman
Property Development to be located at 5215 West Chinden Boulevard in Meridian,
Idaho. The general location of the site is shown on Figure A-1: Site Vicinity Map in
Appendix A of this report. The purpose of this evaluation was to identify subsurface
soil conditions at the site, and provide opinions and recommendations for the proposed
development, relative to earthwork, stormwater disposal, and pavement section
design. This report details the results of our evaluation and presents recommendations
to assist development.
1.0 SCOPE OF SERVICES
Our scope of services for the project included the following:
1) Prior to subsurface exploration, we visited the site to observe site accessibility
and to pre-mark exploration locations, as required by Idaho Digline.
2) Notified Idaho Digline to locate on-site utilities, as required by Idaho state law.
3) Subcontracted a backhoe and operator to observe the excavation of 8 test pits
throughout the site.
4) Visually described, classified, and logged the soils encountered within test pits
and we obtained soil samples within select test pits.
5) Performed seepage tests within select test pits to evaluate subsurface seepage
and installed a PVC pipe within 6 test pits for future groundwater monitoring.
6) Performed laboratory tests on select soil samples to assess some of the soil
engineering properties and characteristics.
7) Reviewed the results of the field evaluation and laboratory testing, performed
engineering analyses, and prepared this report with field and laboratory results,
subsurface logs, and geotechnical-related opinions and recommendations.
We provided our services for the project in general accordance with our geotechnical
proposal (521-113P) dated March 16, 2021.
2.0 PROJECT UNDERSTANDING
Based on electronic communication with you, which included a LandproDATA aerial
image of the site, we understand the project will consist of an approximate 8-acre
residential subdivision development with associated infrastructure, stormwater
disposal facilities, and asphalt-paved roadways. We did not review grading or
development plans, but we anticipate cuts and fills for general site grading to be
approximately 2 feet or less.
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3.0 FIELD EVALUATION PROCEDURES
On April 5, 2021, we observed the excavation of 8 test pits to maximum depths of 10
to 13 feet below the existing ground. We identified subsurface soil conditions, logged
the subsurface soil profiles, and obtained soil samples for laboratory testing. We
performed field seepage testing at select depths within 3 test pits to help evaluate
subsurface soil seepage. At completion of exploration, the test pits were loosely
backfilled with excavated soil approximately level with existing ground surfaces.
Approximate test pit locations are shown on Figure A-2: Exploration Location Plan in
Appendix A.
4.0 SITE CONDITIONS
At the time of exploration most of the site consisted of undeveloped farmland. A
residential building and associated outbuildings were present in the northeast portion
of the site. It is our understanding these structures will be demolished as part of the
development. The site is bordered by Chinden Road to the north, an irrigation ditch
and a residence/farmland to the east, an irrigation ditch and farmland to the south, and
a commercial property (landscape nursery) to the west.
4.1 General Geologic Conditions
The geologic conditions at the site are mapped as Gravel of Whitney Terrace (Qwg)
on the "Geologic Map of the Boise Valley and Adjoining Area, Western Snake River
Plain, Idaho" (by Othberg and Stanford, 1992). These surficial soils are about 16 to 80
feet thick and described as sandy pebble and cobble gravel that are mantled by loess
(Othberg and Stanford, 1992).
The soils encountered within test pits are generally consistent with geologic mapping.
4.2 General Soil Conditions
The USDA Natural Resources Conservation Service (NRCS), which represents the
upper 5 feet of soil profile, has mapped the soils on the site as Power silt loam and
Purdam-Sebree silt loam. Typical soil profiles of these units include silt loam, silty clay
loam, paragravelly silty loam, very sandy loam, cemented material, and stratified sand
to loam. The parent materials of these soils are mixed alluvium, lacustrine deposits,
and/or loess.
The soils encountered within test pits are generally consistent with NRCS mapping.
5.0 EXPLORATION AND SAMPLING
We observed the excavation of test pits with a Case 580C rubber-tired backhoe with a
3-foot-wide bucket. We visually described the soils encountered within test pits
referencing ASTM D 2488, which utilizes the Unified Soil Classification System
(USCS), and we obtained soil samples at select depths for further identification and
GEOTECHNICAL I ENVIRONMENTAL
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Geotechnical Evaluation ALLWEST Project No. 521-113G
Peterman Property Development Page 4
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laboratory testing. We performed seepage testing within 3 test pits on site. We
identified test pit locations on-site with white-flagged stakes or white PVC pipes.
We obtained Google Earth latitude/longitude coordinates of test pit locations with a
hand-held cellular device. These coordinates can be found on test pit logs in Appendix
B and should be considered accurate to the degree implied by the method used.
5.1 Subsurface Soil Conditions
At the time of exploration, we observed majority of test pits within or adjacent to existing
access dirt lanes, so there wasn't surficial vegetation noted. However, based on our
observation of farm field areas, there was approximately 6 inches of surficial topsoil. In
general, the subsurface soils within the observed test pits consisted of surficial native
sandy silts or lean clays underlain by varying thicknesses of weakly indurated silty
sands, overlying silty gravels with sand, poorly-graded gravels with silt and sand,
and/or poorly-graded gravels with sand.
Detailed soil descriptions, depths, and notes are presented on individual test pit logs
in Appendix B. The descriptive soil terms used on the test pit logs in this report, can be
referenced by the USCS. A copy of the USCS is included in Appendix B. Subsurface
conditions may vary between exploration locations. Such changes in subsurface
conditions may not be apparent until construction, and if they change significantly from
those observed, then accordingly, construction timing, plans, and costs may change.
5.2 Subsurface Water
At the time of exploration, we did not encounter groundwater within test pits to the
maximum depths of 10 to 13 feet below existing ground surfaces. Groundwater in the
area is typically influenced by local irrigation and nearby canals, drains, and ditches.
Groundwater may also be influenced by precipitation, on-site construction, and
development to adjacent sites. Subsurface water will fluctuate throughout the different
seasons of the year, but will most likely be affected during seasonal snow melt and
irrigation seasons (March to October).
We installed slotted PVC pipes within 6 test pits throughout the site for future
groundwater monitoring. ALLWEST performed monthly groundwater monitoring from
June through October of 2021; we did not observe/measure groundwater to the bottom
of the installed pipes during this period.
6.0 LABORATORY TESTING
We performed laboratory testing to supplement field classifications and to assess
some of the soil engineering properties and parameters. The laboratory tests
conducted included moisture content (ASTM D 2216), gradation (ASTM D 1140),
Atterberg limits (ASTM D 4318), and California bearing ratio (CBR) (ASTM D 1883).
Laboratory test results are summarized in Appendix C and are also presented on
individual test pit logs in Appendix B, where applicable.
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7.0 CONCLUSIONS AND RECOMMENDATIONS
Based on our field observations, testing, and evaluation, in our opinion the site is
suitable for the planned residential development, provided our recommendations are
adhered to. The following recommendations are presented to assist with planning,
design, and construction of the development, relative to earthwork, utilities, stormwater
disposal, and asphalt pavement section design.
These recommendations are based on our understanding of the proposed
development, the conditions observed within exploration locations, laboratory test
results, and engineering analysis. If the scope of construction changes, or if conditions
are encountered during construction that differ from those described herein, we should
be notified so we can review our recommendations and provide revisions, if necessary.
Foundation-related recommendations are not provided as part of this evaluation.
7.1 Grading and Drainage
We did not review final grading plans for this development, but we anticipate site
grading will consist of cuts and fills of 2 feet or less. We should be notified if actual site
grading varies significantly from this stated information, as it may affect our
recommendations. Final site grading should be such that surfaces slope down and
drain away from any development areas.
7.2 Site Preparation
• Prior to conducting site grading, surficial soil containing vegetation, roots and
organics should be removed below proposed site grading fill areas, pavement
areas, structural areas, and any other development areas. In general, we
anticipate approximately 6 inches of site stripping will be required for most of
the site to remove surficial vegetation and roots (topsoil).
• Where trees are encountered and will be removed as part of the development,
large root systems should be completely over-excavated and replaced with
suitable fill soils. Tree roots depths will not fully be known until construction, but
we anticipate a minimum of 2 to 4 feet of over-excavation will be required to
remove tree roots.
• Where existing structures, outbuildings, and infrastructure are located that will
be demolished as part of this development, complete over-excavation down to
native soils is required, and these over-excavated areas must be replaced with
suitably moisture-conditioned and compacted fill soils. This includes any
existing drain field areas or other previously placed fill areas. This also includes
existing lined or unlined irrigation ditches/laterals, and any soft soils associated
with the ditches/laterals. Lateral limits of existing infrastructure will not fully be
known until construction, and as such, the earthwork contractor should have
contingencies in-place to ensure these areas are fully over-excavated within
future development areas.
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• Loose test pit backfill will settle with time, so where any test pits are located
below proposed pavement, structural, or any development areas, loose test pit
backfill soil must be re-excavated its entire depth and replaced with suitably
moisture-conditioned and compacted fill soils. Over-excavated soils can be
reused to backfill the test pits, provided the soils are not saturated, and they can
achieve the required compaction criteria as required in section 7.6 Fill
Placement and Compaction. Test pit locations that ALLWEST observed are
identified in the field with white-flagged stakes or with white PVC pipes.
Approximate test pit locations are shown on Figure A-2: Exploration Location
Plan. We recommend test pit areas be accurately surveyed so that they may be
located and remediated prior to earthwork construction and development.
• After site stripping, over-excavations, loose test pit remediation, and prior to site
grading, utility/roadway construction, or any other type of development, exposed
subgrades should be proof-rolled with a minimum 5-ton vibratory roller, with
loaded dump trucks, with loaded front-end loaders, or with a vibratory hoe-pack,
to confirm subgrade stability. This will also assist in identifying any soft subgrade
areas. If native subgrades are observed to significantly deflect or pump, the
subgrades should be over-excavated and replaced with properly compacted fills
or stabilized as recommended in section 7.3 Subgrade Stabilization.
7.3 Subgrade Stabilization
If the subgrade soils are observed to pump or deflect significantly during grading, the
subgrades should be stabilized prior to fill placement. Subgrades may be stabilized
using geosynthetic reinforcement in conjunction with imported granular structural fill.
The required thicknesses of granular structural fill (used in conjunction with
geosynthetic reinforcement)will be dependent on the construction traffic loading, which
is unknown at this time. Therefore, a certain degree of trial and error may be required
during construction to verify recommended stabilization section thicknesses.
Geosynthetic reinforcement should consist of Tensar TX-160 or equivalent.
Alternatives to Tensar TX-160 must be approved by the geotechnical engineer prior to
use on site. The following recommendations are provided for subgrade stabilization
using geosynthetic reinforcement.
• Geosynthetic reinforcement materials should be placed on a non-disturbed
subgrade with smooth surface. Loose and disturbed soil should be removed
prior to placement of geosynthetic reinforcement materials.
• A minimum weight 4-ounce, non-woven filter fabric should be placed on the
undisturbed subgrade. The geosynthetic reinforcement should be placed
directly on top of the filter fabric. The filter fabric and geosynthetic reinforcement
should be unrolled in the primary direction of fill placement and should be over-
lapped at least 3 feet, or follow manufacturer's recommendations.
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• The geosynthetic materials should be pulled taut to remove slack.
• Construction equipment should not be operated directly on the geosynthetic
materials. Fill should be placed from outside the excavation to create a pad to
operate equipment on. We recommend a minimum of 12 to 18 inches of
granular structural fill be placed over the geosynthetic reinforcement before
operating construction equipment on the fill. Low pressure, track-mounted
equipment should be used to place fill over the geosynthetic reinforcement.
• Granular structural fill placed directly over geosynthetic reinforcement should be
properly moisture-conditioned prior to placement, and once placed, be statically
rolled. This combination of filter fabric, geosynthetic reinforcement, and granular
structural fill is considered the "bridge" section over soft subgrades.
• After the first "bridge" section has been placed, the remaining fill material above
the "bridge" section should be compacted to structural fill criteria in section 7.6
Fill Placement and Compaction, utilizing vibratory compaction methods.
• Vibration should be discontinued if it reduces the subgrade stability. If
compaction criterion is not met within the fill lift above the "bridge" section, the
"bridge" section thickness is not enough, and subgrade stabilization must be
attempted again with a greater "bridge" section.
The geotechnical engineer or a representative of the geotechnical engineer must be
on-site during subgrade stabilization to verify our recommendations are followed, and
to provide additional recommendations, as needed.
7.4 Excavation
Excavation of on-site soil can be accomplished with typical excavation equipment. We
recommend excavations greater than 4 feet deep be sloped no steeper than 1.5HAV
(horizontal to vertical). Alternatively, deeper excavations may be shored or braced in
accordance with Occupational Safety and Health Administration (OSHA) specifications
and local codes. Regarding trench wall support, the site soil is considered Type C soil
according to OSHA guidelines. Ultimately, the contractor is responsible for site safety,
excavation configurations and following OSHA guidelines.
7.5 Materials
Stripped soils containing vegetation or debris are only suitable for use in non-structural
landscape areas. Existing on-site soils may be reused as site grading fill, provided they
are stockpiled separately, they meet the criteria below, and they are moisture-
conditioned and compacted as required in this report. Imported granular soils should
be free of organics, debris, and other deleterious material and meet the following
criteria. Import materials should be approved by ALLWEST prior to delivery to the site.
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Fill Type Criteria
Site Grading Fill Maximum size <_ 6 inches; ° °
Retained on % inch sieve < 30/°; Liquid limit < 50/°
Maximum size <_ 6 inches;
Granular Structural Fill, Retained on 3/4-inch sieve < 30%;
Granular Subbase Passing No. 200 sieve <_ 15%; Non-plastic
Alternatively, meet ISPWC section 801 6 inches
Maximum size <_ 1 inch;
Crushed Base Course Retained on 3/4-inch sieve < 10%;
Passing No. 200 sieve < 10%; Non-plastic
Alternatively, meet ISPWC section 802 (Type I
Maximum size 5 2 inches;
Utility Trench Backfill Retained on 3/4-inch sieve <°30%;
Passing No. 200 sieve <_ 10/°; Non-plastic
Alternatively, meet ISPWC section 305 (Type I
7.6 Fill Placement and Compaction
Fill should be placed in lift thicknesses which are appropriate for the compaction
equipment used. Typically, 8- to 12-inch-thick loose-lifts are appropriate for typical
rubber-tire and steel-drum compaction equipment. Lift thicknesses should be reduced
to 4 inches for hand-operated compaction equipment. Fill should be moisture-
conditioned to within 2 percentage points of the optimum moisture content prior to
placement to facilitate compaction. Fill should be compacted to the following
percentages of the maximum dry density based on ASTM D 1557 (modified Proctor).
For roadway and utility trench construction only, the local governing jurisdiction may
provide their own method of determining the maximum dry density and compaction
requirements (including subgrade).
Fill Area TCompaction
(0
X-��
Sub rade' Proof-rol12
Site Grading Fill / Granular Structural Fill 95
Granular Subbase/ Crushed Base Course 952
Utility Trench Backfill 922
'Subgrade stability must be verified and approved by a representative of the geotechnical engineer prior
to any fill placement or construction.
2For roadway and utility trench construction only, the local governing jurisdiction may provide their own
method of determining the maximum dry density and compaction requirements (including subgrade).
7.7 Utility Trenches
Support soils for underground utilities will most likely consist of lean clays, sandy silts,
silty sands, and/or poorly-graded gravels with silt and sand. These soils should provide
adequate support for utilities, provided utility subgrades are compacted utilizing
vibratory methods, such as with a large vibratory hoe-pack.
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If utility pipe subgrades are soft, yielding, and/or saturated at the time of construction,
subgrade over-excavation and replacement with competent structural fill may be
required below utilities. If support soils yield and/or are saturated at the time of
construction, we should be notified to observe these soils and provide additional
recommendations, as necessary.
We strongly recommend backfilling trench excavations with fill soils which meet criteria
in section 7.5 Materials, as on-site fine-grained soils (silts and clays) may be difficult to
moisture-condition and compact in utility trenches.
7.8 Wet Weather Construction
We recommend earthwork for this site be scheduled for the drier seasons of the year.
If construction is undertaken in wet periods of the year, it will be important to slope the
ground surface to provide drainage away from construction. If construction occurs
during or immediately after excessive precipitation, it may be necessary to over-
excavate and replace saturated subgrade soil, which might otherwise be suitable.
The on-site soils are sensitive to disturbance when wet. If these soils become wet and
unstable, we recommend construction traffic is minimized where these soils are
exposed. Low ground-pressure (tracked) equipment should be used to minimize
disturbance. Soft and disturbed subgrade areas should be excavated to undisturbed
soil and backfilled with structural fill, compacted to requirements stated in this report.
In addition, it should be noted the on-site soils tend to have notable adhesion when
wet and may be easily transported off-site by construction traffic.
7.9 Cold Weather Construction
The on-site soils are frost susceptible. If site grading and construction are anticipated
during cold weather, we recommend good winter construction practices be observed.
Snow and ice should be removed from excavated areas and fill areas, prior to
additional earthwork or construction. Pavement and flatwork portions of the
construction should not be placed on frozen ground, nor should the supporting soils be
permitted to freeze during or after construction. Frozen soils must not be used as fill.
If native subgrades, or suitably moisture-conditioned and compacted fill lifts, will be left
exposed to freezing temperatures overnight, those areas should be protected with a
minimum of 12 inches of loose soil, or covered with heated construction blankets, so
construction subgrades do not freeze. Any frozen soils should be removed prior to
additional fill placement or construction of any kind.
Earthwork construction during cold inclement weather will require a higher level of
attention and detail to achieve required construction and compaction criteria, and may
lead to additional earthwork requirements and extended construction schedules.
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7.10 Stormwater Disposal
During our field investigation we performed field seepage testing in test pits TP-5, -6,
and -8 within poorly-graded gravels with sand ("clean" gravels) and within poorly-
graded gravels with silt and sand ("dirty" gravels). We obtained field-measured
seepage rates greater than 30 inches per hour (in/hr) within "clean" and "dirty" gravels.
We do not recommend stormwater disposal be accomplished within or above lean
clays, sandy silts, or silty sands due to high fines content (silt/clay) or weak induration,
which exhibit poor and inconsistent soil seepage. Refer to individual test pit logs in
Appendix B to verify soil depths and contacts of soils which are not suitable for
stormwater disposal.
We recommend stormwater disposal occur within poorly-graded gravel soils ("clean"
or "dirty") observed during our field exploration. As such, the following allowable
seepage rate should be utilized for on-site stormwater disposal.
• Poorly-graded gravels ("clean" and "dirty") ............................... 8 in/hr
Stormwater disposal facilities should be constructed a minimum of 1 foot into the
receiving soil. Stormwater disposal facility drain rock and filter sand materials should
maintain a separation/filter fabric between native fine-grained soils and drain rock/filter
sand to help prevent fine-soil migration into drainable/filtering media, as required by
civil design. ALLWEST should observe stormwater disposal facility subgrades to
establish if the suitable receiving soil is encountered (based on civil design depths), to
confirm the allowable seepage rate, and to ensure the separation/filter fabric has been
properly installed (as required by civil design).
The proper separation from bottom of stormwater disposal facilities and seasonal high
groundwater should be maintained. As such, the presence or absence of seasonal
high groundwater should be confirmed via groundwater monitoring throughout
seasonal snow melt and irrigation seasons (March to October), to assist civil
stormwater design.
We installed slotted PVC pipes within 6 test pits throughout the site. ALLWEST
performed monthly groundwater monitoring from June to October of 2021, and we will
commence again in March 2022, until we are asked to stop monitoring.
7.11 Asphalt Pavements
Prior to pavement section construction, the pavement subgrade should be proof-rolled
as recommended in section 7.2 Site Preparation (or as recommended by local
jurisdictions). Local and collector roadways should be designed for a 20-year
Equivalent Single Axle Load (ESAL) of 33,000 and 370,000, respectively, which is
equivalent to a traffic index (TI) of 6 and 8, respectively. If actual traffic conditions are
different than what is stated, we should be notified so that we may modify our pavement
section design.
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Based on existing site grades, it is anticipated that majority of the roadway subgrade
will consist of lean clay or sandy silt soils. We performed CBR testing on a lean clay
soil to evaluate pavement section design, where we obtained a CBR of 6.7, which is
approximately equivalent to an R-value of 15.
The following flexible asphalt pavement section design is provided adhering to the
Idaho Transportation Department (ITD), which utilizes the AASHTO pavement design
methodology. Based on subgrade preparation requirements and design assumptions,
we recommend the following pavement sections be utilized for subdivision roadway
construction for local and collector roadways.
Asphalt Crushed Granular
Pavement Application Concrete Base Course Subbase
(inches) inches inches
Local Roadway 2.5 4 11
Collector Roadway 3 6 14
Base course and subbase should conform to the material recommendations as noted
in this report and should be placed over a properly prepared subgrade. Finished
asphalt surfaces should slope at no less than 2% to help reduce the potential for
surface water infiltration into the underlying pavement sections and subgrade soils. If
the overall site is relatively flat, then finished asphalt surfaces should slope away at no
less than 2% from the crown of the roadways.
Asphalt concrete pavement should be compacted to minimum of 92% of the Rice
density. Crack maintenance on pavements should be performed at a minimum of every
3 years, or when cracking is evident. Crack sealing will help reduce surface water
infiltration into the supporting soils.
8.0 ADDITIONAL RECOMMENDED SERVICES
To maintain continuity and efficiency, we recommend ALLWEST be retained to provide
observations and testing throughout earthwork construction. As an independent testing
company, ALLWEST can document the recommendations included in this report are
properly implemented, provide quality control testing, and observe earthwork for
conformance to project specifications. As a minimum, we recommend the following
testing and observations be provided by ALLWEST:
• Observe site stripping, any over-excavations, compaction of test pit backfill, and
any other soil over-excavations and backfills.
• Observe subgrade proof-rolling and approve subgrades prior to fill construction,
materials placement, or roadway section/utility construction.
• Observe removal of disturbed soil and subgrade stabilization, if required.
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Peterman Property Development Page 12
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• Observe stormwater disposal facility subgrades, confirm subsurface seepage
rates by performing large-scale seepage testing within stormwater disposal
facility locations, and observe overall construction.
• Conduct compaction testing of fill for general site grading, utility backfills, and
pavement subsections.
• Observe placement of/test asphalt for compaction, oil content, and gradation.
If we are not retained to provide the recommended construction observation and
testing services, we shall not be responsible for soil engineering-related construction
errors or omissions.
9.0 EVALUATION LIMITATIONS
This report has been prepared to assist planning, design, and construction of the
proposed Peterman Property Development in Meridian, Idaho. Our services consist of
professional opinions and conclusions made in accordance with generally accepted
geotechnical engineering principles and practices in our local area at the time this
report was prepared. This acknowledgement is in lieu of all warranties either expressed
or implied.
The following appendices complete this report:
Appendix A— Site Vicinity Map, Exploration Location Plan
Appendix B — Test Pit Logs, Unified Soil Classification System
Appendix C — Laboratory Test Results
GEOTECHNICAL I ENVIRONMENTAL
ALLWESTMATERIALS TESTING I SPECIAL INSPECTION
AN EMPLOYEE-OWNED COMPANY
Appendix A
A-1 : Site Vicinity Map
A-2: Exploration Location Plan
ALLWEST
.., .a .Ai 'R
Site
F.r
" 0 2000' 4000'
FIGURE A-1:SITE VICINITY MAP
GEOTECHNICAL EVALUATION
ALLWESTPETERMAN PROPERTY DEVELOPMENT
MERIDIAN, IDAHO
255 N.LINDER ROAD,SUITE 100 CLIENT:TRILOGY DEVELOPMENT
MERIDIAN IDAHO,83642
PHONE:(208)895-7898 FAX:(208)898-3959 PROJECT NO.:521-113G DATE:JANUARY 2022
Boundary
s r
TP-8
0 TP-2 ;; ; : ; : ; ; TP-6'r0
`J� • } i { F 111 � �
7z, t
tom, ~I ; 'v + , � � t . ' • { � � � � •g it
r
-0 TP-3 0 TP-4. TP-5 0, y r
Legend N
0 Approximate location of test pit observed by ALLWEST.
�k Indicates PVC pipe installed in test pit.
0 100' 200'
FIGURE A-2: EXPLORATION LOCATION PLAN
GEOTECHNICAL EVALUATION
ALLWESTPETERMAN PROPERTY DEVELOPMENT
MERIDIAN, IDAHO
255 N.LINDER ROAD,SUITE 100 CLIENT:TRILOGY DEVELOPMENT
MERIDIAN IDAHO,83642
PHONE:(208)895-7898 FAX:(208)898-3959 PROJECT NO.:521-113G DATE:JANUARY 2022
Appendix B
Test Pit Logs
Unified Soil Classification System (USCS)
ALLWEST
ALLWEST DATE STARTED: 4/5/2021 TP - 1
DATE FINISHED: 4/5/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. EXCAVATION METHOD:3-ft wide test pit
TEST PIT LOG LOGGER:Parker Norris
WEATHER:Sunny
PROJECT:521-113G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Peterman Property Development
LATITUDE(DEGREES):N 43°39'45.9144"(43.662754°) U
U LONGITUDE(DEGREES):W-116°27'38.9232" (-116.460812°)
U
u) TOTAL DEPTH: 11' = SAMPLE
CL
w Q
DESCRIPTION W NOTES
Sandy SILT(native); brown,medium dense, moist
1
2
MIL ...weak induration observed throughout soil profile
3
Moisture content=28%
BG Passing No.200 sieve=57%
4 LL=NV, PL=NP, PI=NP
5 Poorly-graded GRAVEL with silt and sand;tan, medium dense,
moist
0
6 GP-GM
0
O
0
7 Poorly-graded GRAVEL with sand;tan,medium dense, moist
0
O
$ o�
o BG
O
9 GP °
O
O
o�
1 O
°b
0
O
1 Test pit terminated at 11 feet(caving).
Slotted PVC pipe installed to 11 feet.
1
1
1
WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 4/5/2021 TP - 2
DATE FINISHED: 4/5/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. EXCAVATION METHOD:3-ft wide test pit
TEST PIT LOG LOGGER:Parker Norris
WEATHER:Sunny
PROJECT:521-113G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Peterman Property Development
LATITUDE(DEGREES):N 43°39'43.3656"(43.662046°) U
U LONGITUDE(DEGREES):W-116°27'39.1104" (-116.460864°)
U
u) TOTAL DEPTH: 11' = SAMPLE
CL
w Q
DESCRIPTION W NOTES
Sandy SILT(native); brown,medium dense, moist
1
2
MIL ...weak induration observed throughout soil profile
3
4
5 Silty SAND;tan,medium dense, moist
BG Moisture content= 12%
6 Passing No.200 sieve=23%
SM
8
9 Poorly-graded GRAVEL with silt and sand;tan, medium dense,
moist
0
GP-GM
1 BG Moisture content=5%
o Passing No.200 sieve=6%
°
1 Test pit terminated at 11 feet(caving).
1
1
1
WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 4/5/2021 TP - 3
DATE FINISHED: 4/5/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. EXCAVATION METHOD:3-ft wide test pit
TEST PIT LOG LOGGER:Parker Norris
WEATHER:Sunny
PROJECT:521-113G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Peterman Property Development
LATITUDE(DEGREES):N 43°39'40.3344"(43.661204°) U
U LONGITUDE(DEGREES):W-116°27'39.1716" (-116.460881°)
U
u) TOTAL DEPTH: 12' = SAMPLE
CL
w Q
DESCRIPTION W NOTES
Lean CLAY(native); brown,stiff, moist
BG
1
CL
2
3 Silty SAND;tan,medium dense, moist
4
5
6
sM ...weak induration observed throughout soil profile
BG
7
8
9
1 Poorly-graded GRAVEL with silt and sand;tan, medium dense,
moist
0
1 GP-GM
0
O
0
1 Test pit terminated at 12 feet(caving).
Slotted PVC pipe installed to 12 feet.
1
1
WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 4/5/2021 TP - 4
DATE FINISHED: 4/5/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. EXCAVATION METHOD:3-ft wide test pit
TEST PIT LOG LOGGER:Parker Norris
WEATHER:Sunny
PROJECT:521-113G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Peterman Property Development
LATITUDE(DEGREES):N 43°39'40.3452"(43.661207°) U
U LONGITUDE(DEGREES):W-116°27'35.0172" (-116.459727°)
U
u) TOTAL DEPTH: 13' = SAMPLE
CL
w Q
DESCRIPTION W NOTES
Lean CLAY(native); brown,stiff, moist
Passing No.200 sieve=89%
1 BK LL=34, PL= 19,PI= 15
CBR=6.7%
2
CL
3
4
5 Silty SAND;tan,medium dense, moist
6
7
...weak induration observed throughout soil profile
SM
9
1
Poorly-graded GRAVEL with silt and sand;tan, medium dense,
moist
1 0
DU
0
GP-GM
0
1
0
0
1 Test pit terminated at 13 feet.
Slotted PVC pipe installed to 13 feet.
1
WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 4/5/2021 TP - 5
DATE FINISHED: 4/5/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. EXCAVATION METHOD:3-ft wide test pit
TEST PIT LOG LOGGER:Parker Norris
WEATHER:Sunny
PROJECT:521-113G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Peterman Property Development
LATITUDE(DEGREES):N 43°39'40.3092"(43.661197°) U
U LONGITUDE(DEGREES):W-116°27'30.816" (-116.45856°)
U
u) TOTAL DEPTH: 11' = SAMPLE
CL
w Q
DESCRIPTION W NOTES
Lean CLAY(fill); brown,firm, moist
00(
00(
1 FILL 00(
00(
2 Lean CLAY(native); brown,stiff, moist
3 cL
4 Silty GRAVEL with sand(native);tan,medium dense, moist
0
5 °
GM Moisture content=7%
° BG Passing No.200 sieve= 13%
6
0
7 Poorly-graded GRAVEL with silt and sand;tan, medium dense,
moist
0
8 ° Field seepage test performed at 8 feet.
O Field seepage rate=>30 in/hr.
°
9 GP-GM
O
0
O
1
°
0
1 Test pit terminated at 11 feet(caving).
Slotted PVC pipe installed to 11 feet.
1
1
1
WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 4/5/2021 TP - 6
DATE FINISHED: 4/5/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. EXCAVATION METHOD:3-ft wide test pit
TEST PIT LOG LOGGER:Parker Norris
WEATHER:Sunny
PROJECT:521-113G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Peterman Property Development
LATITUDE(DEGREES):N 43°39'43.2756"(43.662021°) U
U LONGITUDE(DEGREES):W-116°27'30.8052" (-116.458557°)
U
u) TOTAL DEPTH: 11' = SAMPLE
w Q
DESCRIPTION W NOTES
Lean CLAY(native); brown,stiff, moist Significant roots and vegetation observed to 6
inches.
1
2— CL
3
4 Silty SAND;tan,medium dense, moist
5 sM
6 Poorly-graded GRAVEL with silt and sand;tan, medium dense,
moist
0
GP-GM o
O
Field seepage test performed at 8 feet.
8
Poorly-graded GRAVEL with sand;tan,medium dense, moist Field seepage rate=>30 in/hr.
0
O
O
9 0�
GP
O
o�
1 0
O
o�
0
1 Test pit terminated at 11 feet(caving).
1
1
1
—75 WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 4/5/2021 TP - 7
DATE FINISHED: 4/5/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. EXCAVATION METHOD:3-ft wide test pit
TEST PIT LOG LOGGER:Parker Norris
WEATHER:Sunny
PROJECT:521-113G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Peterman Property Development
LATITUDE(DEGREES):N 43°39'45.9396"(43.662761°) U
U LONGITUDE(DEGREES):W-116°27'35.0064" (-116.459724°)
U
u) TOTAL DEPTH: 10' = SAMPLE
w Q
DESCRIPTION W NOTES
Lean CLAY(native); brown,stiff, moist
1 cL
2 Silty SAND;tan,medium dense, moist
3
4
sM ...weak induration observed throughout soil profile
5 BG Moisture content=6%
Passing No.200 sieve=40%
6—
Poorly-graded GRAVEL with silt and sand;tan, medium dense,
moist
0
8 0
GP-GM
0
9 0
0
O
1 Test pit terminated at 10 feet(caving).
Slotted PVC pipe installed to 10 feet.
1
1
1
1
WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
ALLWEST DATE STARTED: 4/5/2021 TP - 8
DATE FINISHED: 4/5/2021 EXCAVATOR: CASE 580C
MERIDIAN,IDAHO OPERATOR:Steve Just
GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. EXCAVATION METHOD:3-ft wide test pit
TEST PIT LOG LOGGER:Parker Norris
WEATHER:Sunny
PROJECT:521-113G NOTES:See Figure A-2 in Appendix A for approximate test pit location.
Peterman Property Development
LATITUDE(DEGREES):N 43°39'43.3908"(43.662053°) U
U LONGITUDE(DEGREES):W-116°27'34.9092" (-116.459697°)
U
u) TOTAL DEPTH: 11' = SAMPLE
w Q
DESCRIPTION W NOTES
Lean CLAY(native); brown,stiff, moist
1
CL
2
3 Silty SAND;tan,medium dense, moist
4
sM ...weak induration observed throughout soil profile
5
6 Poorly-graded GRAVEL with silt and sand;tan, medium dense,
moist
0
7-
8— o BG Moisture content=6%
Passing No.200 sieve= 11%
GP-GM o Field seepage test performed at 8.5 feet.
o Field seepage rate=>30 in/hr.
9
0
O
1 0
0
0
1 Test pit terminated at 11 feet(caving).
Slotted PVC pipe installed to 11 feet.
1
1
1
WATER LEVELS
a WHILE EXCAVATING
Y AT COMPLETION
1 AFTER EXCAVATING Sheet 1 of 1
Unified Soil Classification System
MAJOR DIVISIONS SYMBOL TYPICAL NAMES
Well-Graded Gravel,
CLEAN GW Gravel-Sand Mixtures.
GRAVELS GP Poorly-Graded Gravel,
GRAVELS Gravel-Sand Mixtures.
Silty Gravel,
COARSE GRAVELS GM Gravel-Sand-Silt Mixtures.
GRAINED WITH FINES GC Clayey Gravel,
SOILS Gravel-Sand-Clay Mixtures.
Well-Graded Sand,
CLEAN SW Gravelly Sand.
SANDS SP Poorly-Graded Sand,
SANDS Gravelly Sand.
Silty Sand,
SANDS L SM Sand-Silt Mixtures.
WITH FINES Sc Clayey Sand,
Sand-Clay Mixtures.
ML Inorganic Silt,
SILTS AND CLAYS Silty or Clayey Fine Sand.
Inorganic Clay of Low to
LIQUID LIMIT CL Medium Plasticity,
LESS THAN 50% Sandy or Silty Clay.
FINE OL Organic Silt and Clay of Low
GRAINED Plasticity.
SOILS Inorganic Silt, Elastic Silt,
SILTS AND CLAYS MH Micaceous Silt,
Fine Sand or Silt.
LIQUID LIMIT CH Inorganic Clay of High Plasticity,
GREATER THAN 50% Fat Clay.
OH Organic Clay of Medium to High
Plasticity.
Highly Organic Soils PT Peat, Muck and Other Highly
Organic Soils.
ALLWEST
Appendix C
Laboratory Test Results
ALLWEST
Summary of Laboratory Test Results
Moisture Gradation Atterberg Limits
Test Pit Depth Liquid Plasticity CBR Sample Classification
No. (Feet) Content Gravel/Sand Silt/Clay Limit Index % USCS
1 3.5 -4 28 43 57 NV* NP* Sandy SILT (ML)
2 5.5 -6 12 77 23 Silty SAND SM
2 10 - 10.5 5 94 6 Poorly-Graded GRAVEL with Silt and Sand (GP-GM)
4 0.5- 1.5 - 11 89 34 15 6.7 Lean CLAY CL
5 5.5 - 6 7 87 13 Silty GRAVEL with Sand GM
7 5- 5.5 6 60 40 Silty SAND (SM)
8 8- 8.5 6 89 11 Poorly-Graded GRAVEL with Silt and Sand (GP-GM)
* NV/ NP = No Value/ Non Plastic
Table C-1
255 N. Linder Road, Suite 100 • Meridian, Idaho 83642 • (208) 895-7895 • Fax (208) 898-3959
www.allwesttesting.com
This report may not be reproduced, except in full, without the permission of ALLWEST.
LIQUID AND PLASTIC LIMITS TEST REPORT
60
Dashed line indicates the approximate
upper limit boundary for natural soils
50 O
�0
' G
40
U
C �
X
W
N— Z_
�
v 30
c F-
LU C/) '
Q i
J /
a� 20
H
U)
LU
■
,
J /
J
Q 10
0 ;
c
L-ML ML or OL MH or OH
0
0 10 20 30 40 50 60 70 80 90 100 110
LIQUID LIMIT
0 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS
• Sandy Silt NV NP NP 57% ML
c■ Lean Clay 34 19 15 89% CL
CD
U
X
U
U
U
7
O
` Project No. 521-113G Client: Trilogy Development Remarks:
aD Project: Peterman Property Development
c *Location: TP-1 Depth: 3.5'-4'
■Location: TP-4 Depth: 0.5'-1.5'
0
En
ALLWEST
E
H Figure C-1
Tested By: C. Downes Checked By:J.Varozza
California Bearing Ratio
ASTM D 1883
Project: Peterman Property Development Project No.: 521-113G
Client: Trilogy Development Location: TP-4 @ 0.5 - 1.5 ft
Date Tested: 5/2021 Compaction Method: ASTM D1557
Tested By: C. Downes Classification: Lean Clay (CL)
175
150
125
a
c 100
'a
c
75
PSI @ 0.1 inch penetration= 67
50
25
0
0 0.1 0.2 0.3 0.4 0.5
Penetration(inches)
CBR @ 0.1 Inch Penetration: 6.7 Maximum Dry Unit Weight (pcf): 114.6
Swell (%): 2.7 Optimum Water Content (%): 13.6
Dry Unit Weight Before Soak(pcf): 104.5 Remold of Max. Dry Unt Wgt(%): 91
Water Content Before Soak (%): 14.2
Water Content After Soak, Top 1 Inch (%): 43.8
Surcharge (psf): 50
Immersion Period (hrs): 96
Reviewed By: Adrian Mascorro
Figure: C-2
►LLIIET
255 N Linder Rd,Suite 100•Meridian,ID 83642•(208)895-7898•Fax(208)898-3959
www.allwesttesting.com
This report shall not be reproduced except in full without the permission of ALLW EST.