HomeMy WebLinkAboutFORT COLLINS NISSAN-KIA - PDP210017 - SUBMITTAL DOCUMENTS - ROUND 3 - GEOTECHNICAL (SOILS) REPORT
REPORT COVER PAGE
Geotechnical Engineering Report
__________________________________________________________________________
Fort Collins Nissan and Kia Dealerships – Retention Pond
Fort Collins, Colorado
January 25, 2022
Terracon Project No. 20215013A
Prepared for:
TCC Corporation
Windsor, Colorado
Prepared by:
Terracon Consultants, Inc.
Fort Collins, Colorado
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REPORT TOPICS
INTRODUCTION ............................................................................................................. 1
SITE CONDITIONS ......................................................................................................... 1
PROJECT DESCRIPTION .............................................................................................. 2
EXPLORATION AND TESTING PROCEDURES ........................................................... 2
GEOTECHNICAL CHARACTERIZATION ...................................................................... 4
GEOTECHNICAL OVERVIEW ....................................................................................... 6
GENERAL COMMENTS ................................................................................................. 6
Note: This report was originally delivered in a web-based format. Orange Bold text in the report indicates a referenced
section heading. The PDF version also includes hyperlinks which direct the reader to that section and clicking on the
GeoReport logo will bring you back to this page. For more interactive features, please view your project online at
client.terracon.com.
ATTACHMENTS
EXPLORATION AND TESTING PROCEDURES
SITE LOCATION AND EXPLORATION PLANS
EXPLORATION RESULTS
SUPPORTING INFORMATION
Note: Refer to each individual Attachment for a listing of contents.
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INTRODUC TION
Geotechnical Engineering Report
Fort Collins Nissan and Kia Dealerships – Retention Pond
West of South College Avenue and Crestridge Drive
Fort Collins, Colorado
Terracon Project No. 20215013A
January 25, 2022
INTRODUCTION
This report presents the results of our subsurface exploration and groundwater monitoring well
installation for the proposed Fort Collins Nissan and Kia Dealerships Retention Pond to be located
west of the intersection of South College Avenue and Crestridge Drive in Fort Collins, Colorado.
The purpose of these services is to provide information and geotechnical engineering
recommendations relative to:
■ Subsurface soil and rock conditions ■ Groundwater conditions
■ Monitoring well installation
The geotechnical engineering scope of services for this project included the advancement of three
(3) test borings completed as temporary piezometers to depths ranging from approximately 15 to
20 feet below existing site grades.
Maps showing the site and boring locations are shown in the Site Location and Exploration
Plan sections, respectively. The results of the laboratory testing performed on soil and bedrock
samples obtained from the site during the field exploration are included on the boring logs and as
separate graphs in the Exploration Results section of this report.
SITE CONDITIONS
The following description of site conditions is derived from our site visit in association with the
field exploration and our review of publicly available geologic and topographic maps.
Item Description
Parcel Information
The project site is located west of the intersection of South College Avenue
and West Crestridge Drive in Fort Collins, Colorado. The approximate
Latitude/Longitude of the center of the site is 40.5066° N/105.0782°W (Please
refer to Site Location).
Existing
Improvements
The north portion of the site is currently vacant land with some two-track roads
and walking trails. The south portion of the site is currently occupied by an
existing Nissan Dealership and associated parking and drive areas.
Geotechnical Engineering Report
Fort Collins Nissan and Kia Dealerships – Retention Pond ■ Fort Collins, Colorado
January 25, 2022 ■ Terracon Project No. 20215013A
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Item Description
Surrounding
Developments
The site is bordered to the west by vacant land followed by an existing railroad
and single-family residential developments. To the north of the site is the
existing Fossil Creek followed by vacant land and single-family residential
developments. To the east and south of the site are commercial
developments followed by single-family residential developments
Current Ground
Cover
The current ground cover in the area of exploration was native grasses and
weeds.
Existing Topography The site has rolling hills and generally slopes from south to north towards
Fossil Creek.
PROJECT DESCRIPTION
Our final understanding of the project conditions is as follows:
Item Description
Information Provided
Project information presented herein is based on the following
■ Conversation with the client and project team
■ Additional requested boring locations
■ A preliminary site plan with comments from the project team, provided
at the time of the previous Geotechnical Engineering Study
Project Description
We understand the project includes the demolition of the existing Nissan
dealership building and the construction of a new Nissan and Kia dealerships.
Parking and drive areas, access lanes, a new roadway and new utilities are
also planned for the project. We understand the project will also include three
potential retention ponds on the west side of the site.
Grading/Slopes We anticipate cuts and fills on the order of 10 to 15 feet will likely be required
to the proposed retention ponds.
If project information or assumptions vary from what is described above or if location of
construction changes, we should be contacted as soon as possible to confirm and/or modify our
recommendations accordingly.
EXPLORATION AND TESTING PROCEDURES
Field Exploration
TCC prescribed the following boring locations and depths:
Number of Borings Boring Depth (feet) Location
3 15 to 20 Planned retention pond areas
Geotechnical Engineering Report
Fort Collins Nissan and Kia Dealerships – Retention Pond ■ Fort Collins, Colorado
January 25, 2022 ■ Terracon Project No. 20215013A
Responsive ■ Resourceful ■ Reliable 3
Boring Layout and Elevations: We used handheld GPS equipment to locate borings with an
estimated horizontal accuracy of +/-20 feet. A ground surface elevation at each boring location
was obtained by Terracon by approximating from google earth.
Subsurface Exploration Procedures: We advanced soil borings with a truck-mounted drill rig
using continuous-flight, solid-stem augers. Three samples were obtained in the upper 10 feet of
each boring and at intervals of 5 feet thereafter. Soil sampling were performed using modified
California barrel and standard split -barrel sampling procedures. For the standard split-barrel
sampling procedure, a standard 2 -inch outer diameter split-barrel sampling spoon is driven into
the ground by a 140 -pound automatic hammer falling a distance of 30 inches. The number of
blows required to advance the sampling spoon t he last 12 inches of a normal 18-inch penetration
is recorded as the Standard Penetration Test (SPT) resistance value. The SPT resistance values,
also referred to as N-values, are indicated on the boring logs at the test depths. For the modified
California barrel sampling procedure, a 2½-inch outer diameter split-barrel sampling spoon is
used for sampling. Modified California barrel sampling procedures are similar to standard split -
barrel sampling procedures; however, blow counts are typically recorded for 6-inch intervals for a
total of 12 inches of penetration. The samples were placed in appropriate containers, taken to our
soil laboratory for testing, and classified by a geotechnical engineer.
In addition, we observed and recorded groundwater levels during drilling observations and several
days after drilling.
Our exploration team prepared field boring logs as part of standard drilling operations including
sampling depths, penetration distances, and other relevant sampling information. Field logs
included visual classifications of materials encountered during drilling, and our interpretation of
subsurface conditions between samples. Final boring logs, prepared from field logs, represent
the geotechnical engineer's interpretation, and include modifica tions based on observations and
laboratory test results.
Temporary Piezometers: The three borings in the areas of the proposed retention ponds were
completed as temporary piezometers. Temporary piezometers were registered with the State
Engineering department and we re constructed as follows.
■ Installation of about 15 to 20 feet of 2-inch diameter, slotted polyvinyl chloride (PVC) pipe
and about 5 to 10 feet of solid PVC pipe with an end cap
■ Addition of pre-sieved 20/40 grade silica sand for annular sand pack around the wel l
screen from the bottom of the boring to approximately 1 foot below the ground surface
■ Placement of about 1 foot of bentonite chips above the sand pack, grout was placed up to
the ground surface to seal the piezometer and minimize the influence of irrigat ion
■ The temporary piezometer was capped with a flush mounted well top and sealed with a
small concrete apron around each of the piezometer lids.
Geotechnical Engineering Report
Fort Collins Nissan and Kia Dealerships – Retention Pond ■ Fort Collins, Colorado
January 25, 2022 ■ Terracon Project No. 20215013A
Responsive ■ Resourceful ■ Reliable 4
We observed and recorded groundwater levels during drilling observations and several days after
drilling. Piezometers were left for future monitoring; Terracon is available to continue to check
the piezometers upon request, however no provisions have been made to obtain additional
delayed groundwater measurements at this time.
Property Disturbance: Upon completion of drilling the boreholes and piezometer installation,
excess auger cuttings were dispersed in the general vicinity of the boreholes. Unless instructed
by the client to register the monitoring wells as permeant, we will remove and abandon the
piezometers within 18 months of construction, as required by the State Engineering Department.
Removal of the wells will include removal of well materials and grouting the boreholes
Laboratory Testing
The project engineer reviewed field data and assigned variou s laboratory tests to better
understand the engineering properties of various soil and bedrock strata. Laboratory testing was
conducted in general accordance with applicable or other locally recognized standards.
Procedural standards noted in this report are for reference to methodology in general. In some
cases, variations to methods are applied as a result of local practice or professional judgement.
Testing was performed under the direction of a geotechnical engineer and included the following:
■ Visual classification ■ Moisture content
■ Dry density ■ Atterberg limits
■ Grain-size analysis
Our laboratory testing program includes examination of soil samples by an engineer. Based on
the material’s texture and plasticity, we described and classified soil samp les in accordance with
the Unified Soil Classification System (USCS). Soil and bedrock samples obtained during our
field work will be disposed of after laboratory testing is complete unless a specific request is made
to temporarily store the samples for a longer period of time.
Bedrock samples obtained had rock classification conducted using locally accepted practices for
engineering purposes. Boring log rock classification is determined using the Description of Rock
Properties.
GEOTECHNICAL CHARACTERIZAT ION
Subsurface Profile
Subsurface conditions encountered in the borings completed for the temporary piezometers
generally consisted of interbedded claystone and sandstone bedrock which was encountered
from the surface. Boring B3, the eastern most boring, encountered silty to clayey sand which
extended to the maximum depth of exploration of about 15 feet below existing site grades.
Geotechnical Engineering Report
Fort Collins Nissan and Kia Dealerships – Retention Pond ■ Fort Collins, Colorado
January 25, 2022 ■ Terracon Project No. 20215013A
Responsive ■ Resourceful ■ Reliable 5
We have developed a general characterization of the subsurface conditions based upon our
review of the subsurface exploration, laboratory data, geologic setting and our understanding of
the project. This characterization, termed GeoModel, forms the basis of our geotechnical
calculations and evaluation of site preparation and foundation options. Conditions encountered at
each exploration point are indicated on the individual logs. The individual logs and the GeoModel
can be found in the Exploration Results section this report.
Model Layer Layer Name General Description Approximate Depth to
Bottom of Stratum
1 Silty to clayey
sand
Silty to clayey sand, red brown with
gray, loose to medium dense. Only
encountered in piezometer B3.
To the maximum depth of
exploration of about 15 feet
below existing site grades.
2 Bedrock
Interbedded claystone and sandstone,
tan to gray, hard to very hard.
To the maximum depths of
exploration of about 15 to 20
feet below existing grades.
As noted in General Comments, this characterization is based upon widely spaced exploration
points across the site and variations are likely.
Groundwater Conditions
The boreholes were observed while drilling and shortly after completion for the presence and level
of groundwater. In addition, delayed water levels were also obtained in the borings. The water
levels observed in the boreholes are noted on the attached logs, and are summarized below:
Piezometer
Number
Depth to
Groundwater While
Drilling, ft.
Depth to
Groundwater After
Drilling, ft.
Depth to
Groundwater on
1/25/2022, ft.
Elevation of
Groundwater on
1/25/2022, ft.1
B1 Not encountered while drilling 13.8 4,995.2
B2 Not encountered while drilling 10.8 4,995.2
B3 11.9 12.7 10.9 5,002.1
1. Elevation of groundwater is based on the ground surface elevation of the piezometers, estimated from google earth.
These observations represent short-term groundwater conditions at the time of and shortly after
the field exploration and may not be indicative of other times or at other locations. Groundwater
levels can be expected to fluctuate with varying seasonal and weather conditions, and other
factors.
Groundwater level fluctuations occur due to seasonal variations in the water levels present in
nearby water features, amount of rainfall, runoff and other factors not evident at the time the
borings were performed. Therefore, groundwater levels during construction or at other times in
the life of the proposed pond may be higher or lower than the levels indicated on the boring logs.
Geotechnical Engineering Report
Fort Collins Nissan and Kia Dealerships – Retention Pond ■ Fort Collins, Colorado
January 25, 2022 ■ Terracon Project No. 20215013A
Responsive ■ Resourceful ■ Reliable 6
The possibility of groundwater level fluctuations should be considered when developing the
design and construction plans for the project.
Laboratory Testing
Samples of site soils and bedrock selected for plasticity testing exhibited low to moderate plasticity
with liquid limits ranging from non-plastic to 31 and plasticity indices ranging from non-plastic to
13. Laboratory test results are presented in the Exploration Results section of this report.
GEOTECHNICAL OVERVIEW
Based on subsurface conditions encountered in the borings, the site appears suitable for the
proposed construction from a geotechnical point of view provided certain precautions and design
and construction recommendations described in this report a re followed. We have identified
shallow bedrock as a geotechnical condition that could impact the design and construction of the
proposed retention ponds. This condition will require particular attention in p roject planning,
design and during construction and are discussed in greater detail in the following sections.
Shallow Bedrock
As previously stated, bedrock was encountered in two of the borings completed for the
piezometers at the ground surface. Excavation penetrating the bedrock may require the use of
specialized heavy-duty equipment to advance the excavation and facilitate ro ck break-up and
removal. Consideration should be given to obtaining a unit price for difficult excavation in the
contract documents for the project.
Shallow Groundwater
As previously stated, groundwater was measured at depths ranging from about 10.8 to 13.8 feet
below existing site grades It is also possible and likely that groundwater levels below this site
may rise as water levels in nearby water features rise. Final site grading should be planned and
designed to avoid cuts where shallow groundwater is known to exist, and also in areas where
such grading would create shallow groundwater conditions.
The General Comments section provides an understanding of the report limitations.
GENERAL COMMENTS
Our analysis and opinions are based upon our understanding of the project, the geotechnical
conditions in the area, and the data obtained from our site exploration. Natural variations will occur
between exploration point locations or due to the modifying effec ts of construction or weather.
Geotechnical Engineering Report
Fort Collins Nissan and Kia Dealerships – Retention Pond ■ Fort Collins, Colorado
January 25, 2022 ■ Terracon Project No. 20215013A
Responsive ■ Resourceful ■ Reliable 7
The nature and extent of such va riations may not become evident until during or after construction.
Terracon should be retained as the Geotechnical Engineer, whe re noted in this report, to provide
observation and testing services during pertinent construction phases. If variations appear, we
can provide further evaluation and supplemental recommendations. If variations are noted in the
absence of our observation and testing services on-site, we should be immediately notified so
that we can provide evaluation and supplemen tal recommendations.
Our Scope of Services does not include either specifically or by implication any environmental or
biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of
pollutants, hazardous materials or conditions. If the owner is concerned about the potential for
such contamination or pollution, other studies should be undertaken.
Our services and any correspondence or collaboration through this system are intended for the
sole benefit and exclusive use of our client for specific application to the project discussed and
are accomplished in accordance with generally accepted geotechnical engineering practices with
no third-party beneficiaries intended. Any third-party access to services or correspondence is
solely for information purposes to support the services provided by Terracon to our client.
Reliance upon the services and any work product is l imited to our client, and is not intended for
third parties. Any use or reliance of the provided information b y third parties is done solely at their
own risk. No warranties, either express or implied, are intended or made.
Site characteristics as provided are for design purposes and not to estimate excavation cost. Any
use of our report in that regard is done a t the sole risk of the excavating cost estimator as there
may be variations on the site that are not apparent in the data that could significantly impact
excavation cost. Any parties charged with estimating excavation costs should seek their own site
characterization for specific purposes to obtain the specific level of detail necessary for costing.
Site safety, and cost estimating including, excavation support, and dewatering
requirements/design are the responsibility of others. If changes in the nature, design, or location
of the project are planned, our conclusions and recommendations shall not be considered valid
unless we review the changes and either verify or modify our conclusions in writing.
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ATTACHMENTS
Contents:
SITE LOCATION AND EXPLORATION PLANS
EXPLORATION RESULTS
SUPPORTING INFORMATION
Note: Refer to each individual Attachment for a listing of contents.
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SITE LOCATION AND EXPLORATIO N PLANS
Contents:
Site Location Plan
Exploration Plan
Note: All attachments are one page unless noted above.
SITE LOCATION
Fort Collins Nissan and Kia Dealerships – Retention Pond ■ Fort Collins, Colorado
January 25, 2022 ■ Terracon Project No. 20215013A
Note to Preparer: This is a large table with outside borders. Just click inside the table
above this text box, then paste your GIS Toolbox image.
When paragraph markers are turned on you may notice a line of hidden text above and
outside the table – please leave that alone. Limit editing to inside the table.
The line at the bottom about the general location is a separate table line. You can edit
it as desired, but try to keep to a single line of text to avoid reformatting the page.
SITE LOCA TION
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES MAP PROVIDED BY MICROSOFT BING MAPS
EXPLORATION PLAN
Fort Collins Nissan and Kia Dealerships – Retention Pond ■ Fort Collins, Colorado
January 25, 2022 ■ Terracon Project No. 20215013A
Note to Preparer: This is a large table with outside borders. Just click inside the table
above this text box, then paste your GIS Toolbox image.
When paragraph markers are turned on you may notice a line of hidden text above and
outside the table – please leave that alone. Limit editing to inside the table.
The line at the bottom about the general location is a separate table line. You can edit
it as desired, but try to keep to a single line of text to avoid reformatting the page.
EXPLORATION P LAN
DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES MAP PROVIDED BY MICROSOFT BING MAPS
EXPLORATION RESULTS
Contents:
GeoModel
Piezometer Logs (3 pages)
Atterberg Limits
Grain Size Distribution
Note: All attachments are one page unless noted above.
4,988
4,990
4,992
4,994
4,996
4,998
5,000
5,002
5,004
5,006
5,008
5,010
5,012
5,014
ELEVATION(MSL)(feet)Fort Collins Nissan and Kia Dealerships - Retention Pond Fort Collins, CO
Terracon Project No. 20215013A
Layering shown on this figure has been developed by the
geotechnical engineer for purposes of modeling the subsurface
conditions as required for the subsequent geotechnical engineering
for this project.
Numbers adjacent to soil column indicate depth below ground
surface.
NOTES:
GEOMODEL
This is not a cross section. This is intended to display the Geotechnical Model only. See individual logs for more detailed conditions.
Groundwater levels are temporal. The levels shown are representative of the date
and time of our exploration. Significant changes are possible over time.
Water levels shown are as measured during and/or after drilling. In some cases,
boring advancement methods mask the presence/absence of groundwater. See
individual logs for details.
First Water Observation
Second Water Observation
Third Water Observation
LEGEND
Bedrock
Clayey Sand
Sandy Silt
Model Layer General DescriptionLayer Name
Clayey sand to sandy silt, red brown with gray, loose to
medium dense. Only encountered in piezometer B3.1
Interbedded claystone and sandstone, tan to gray, hard to
very hard.2
B1
B2
B3
Vegetative Soil Layer
Clayey sand to sandy
silt
Bedrock
20
2
13.8
15
2
10.8
15
10.9
1
12.7
11.9
11.8
10.5
11.1
10.6
8.9
110
108
128
31-18-13 62
Well Cap
Bentonite
Chips
Sand
Solid PVC Pipe
Slotted PVC
Pipe
5008.5
4989
50/4"
50/6"
50/2"
50/2"
50/2"
0.5
20.0
VEGETATIVE LAYER, approximately 3
to 6 inches
CLAYSTONE (CL), tan, very hard
SANDSTONE/CLAYSTONE, gray, very
hard
Boring Terminated at 20 Feet
Stratification lines are approximate. In-situ, the transition may be gradual.Hammer Type: Automatic
THISBORINGLOGISNOTVALIDIFSEPARATEDFROMORIGINALREPORT.GEOSMARTLOG-WELL20215013AFORTCOLLINSNISS.GPJTERRACON_DATATEMPLATE.GDT1/25/22WATERCONTENT(%)DRYUNITWEIGHT(pcf)ATTERBERG
LIMITS
LL-PL-PI
PERCENTFINESSAMPLETYPEDEPTH(Ft.)5
10
15
20 WATERLEVELOBSERVATIONSINSTALLATION
DETAILS
Surface Elev.: 5009 (Ft.)
ELEVATION (Ft.)FIELDTESTRESULTSPage 1 of 1
Advancement Method:
4-inch diameter, solid-stem augers
Abandonment Method:
Borehole completed as temporary piezometer
Notes:
Project No.: 20215013A
Drill Rig: CME-55
PIEZOMETER LOG NO. B1
TCC CorporationCLIENT:
Windsor, CO
Driller: Drilling Engineers, Inc.
Boring Completed: 12-16-2021
PROJECT: Fort Collins Nissan and Kia Dealerships -
Retention Pond
Elevation obtained by approximating from google
earth
See Exploration and Testing Procedures for a
description of field and laboratory procedures used
and additional data (If any).
See Supporting Information for explanation of
symbols and abbreviations.
West of South College Avenue and Crestridge Drive
Fort Collins, CO
SITE:
Boring Started: 12-16-2021
1901 Sharp Point Dr Ste C
Fort Collins, CO
no free water observed while drilling
13.8' on 1/25/22
WATER LEVEL OBSERVATIONSMODELLAYERGRAPHICLOGLOCATIONSeeExploration Plan
Latitude: 40.5059° Longitude: -105.0804°
DEPTH
2
9.9
11.1
9.3
8.6
114
121
31-21-10 51
Well Cap
Bentonite
Chips
Solid PVC Pipe
Sand
Slotted PVC
Pipe
5005.5
4991
31-50/5"
50/3"
50/1"
50/2'
0.5
15.0
VEGETATIVE LAYER, approximately 6
inches
CLAYSTONE/SANDSTONE (CL), tan,
very hard
brown to gray
gray
Boring Terminated at 15 Feet
Stratification lines are approximate. In-situ, the transition may be gradual.Hammer Type: Automatic
THISBORINGLOGISNOTVALIDIFSEPARATEDFROMORIGINALREPORT.GEOSMARTLOG-WELL20215013AFORTCOLLINSNISS.GPJTERRACON_DATATEMPLATE.GDT1/25/22WATERCONTENT(%)DRYUNITWEIGHT(pcf)ATTERBERG
LIMITS
LL-PL-PI
PERCENTFINESSAMPLETYPEDEPTH(Ft.)5
10
15 WATERLEVELOBSERVATIONSINSTALLATION
DETAILS
Surface Elev.: 5006 (Ft.)
ELEVATION (Ft.)FIELDTESTRESULTSPage 1 of 1
Advancement Method:
4-inch diameter, solid-stem augers
Abandonment Method:
Borehole completed as temporary piezometer
Notes:
Project No.: 20215013A
Drill Rig: CME-55
PIEZOMETER LOG NO. B2
TCC CorporationCLIENT:
Windsor, CO
Driller: Drilling Engineers, Inc.
Boring Completed: 12-16-2021
PROJECT: Fort Collins Nissan and Kia Dealerships -
Retention Pond
Elevation obtained by approximating from google
earth
See Exploration and Testing Procedures for a
description of field and laboratory procedures used
and additional data (If any).
See Supporting Information for explanation of
symbols and abbreviations.
West of South College Avenue and Crestridge Drive
Fort Collins, CO
SITE:
Boring Started: 12-16-2021
1901 Sharp Point Dr Ste C
Fort Collins, CO
no free water observed while drilling
10.8' on 1/25/22
WATER LEVEL OBSERVATIONSMODELLAYERGRAPHICLOGLOCATIONSeeExploration Plan
Latitude: 40.5065° Longitude: -105.0806°
DEPTH
2
6.9
8.0
19.5
18.5
114
110
27-16-11
NP
33
59
Well Cap
Bentonite
Chips
Solid PVC Pipe
Sand
Slotted PVC
Pipe
5012
5004
4998
7-5-6
N=11
8-6
8-6-7
N=13
11-22
0.8
9.0
15.0
VEGETATIVE LAYER, approximately 8
inches
CLAYEY SAND (SC), red brown, loose
to medium dense
SANDY SILT (ML), red brown and gray,
medium dense
Boring Terminated at 15 Feet
Stratification lines are approximate. In-situ, the transition may be gradual.Hammer Type: Automatic
THISBORINGLOGISNOTVALIDIFSEPARATEDFROMORIGINALREPORT.GEOSMARTLOG-WELL20215013AFORTCOLLINSNISS.GPJTERRACON_DATATEMPLATE.GDT1/25/22WATERCONTENT(%)DRYUNITWEIGHT(pcf)ATTERBERG
LIMITS
LL-PL-PI
PERCENTFINESSAMPLETYPEDEPTH(Ft.)5
10
15 WATERLEVELOBSERVATIONSINSTALLATION
DETAILS
Surface Elev.: 5013 (Ft.)
ELEVATION (Ft.)FIELDTESTRESULTSPage 1 of 1
Advancement Method:
4-inch diameter, solid-stem augers
Abandonment Method:
Borehole completed as temporary piezometer
Notes:
Project No.: 20215013A
Drill Rig: CME-55
PIEZOMETER LOG NO. B3
TCC CorporationCLIENT:
Windsor, CO
Driller: Drilling Engineers, Inc.
Boring Completed: 12-16-2021
PROJECT: Fort Collins Nissan and Kia Dealerships -
Retention Pond
Elevation obtained by approximating from google
earth
See Exploration and Testing Procedures for a
description of field and laboratory procedures used
and additional data (If any).
See Supporting Information for explanation of
symbols and abbreviations.
West of South College Avenue and Crestridge Drive
Fort Collins, CO
SITE:
Boring Started: 12-16-2021
1901 Sharp Point Dr Ste C
Fort Collins, CO
11.9' while drilling
12.7' after drilling
10.9' on 1/25/22
WATER LEVEL OBSERVATIONSMODELLAYERGRAPHICLOGLOCATIONSeeExploration Plan
Latitude: 40.5062° Longitude: -105.0800°
DEPTH
1
0
10
20
30
40
50
60
0 20 40 60 80 100CH or OHCL or OLML or OL
MH or OH"U" Line"A " LineATTERBERG LIMITS RESULTS
ASTM D4318
P
L
A
S
T
I
C
I
T
Y
I
N
D
E
X
LIQUID LIMIT
1901 Sharp Point Dr Ste C
Fort Collins, CO
PROJECT NUMBER: 20215013A
SITE: West of South College Avenue and
Crestridge Drive
Fort Collins, CO
PROJECT: Fort Collins Nissan and Kia
Dealerships - Retention Pond
CLIENT: TCC Corporation
Windsor, CO
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. ATTERBERG LIMITS 20215013A FORT COLLINS NISS.GPJ TERRACON_DATATEMPLATE.GDT 1/22/2231
31
27
NP
18
21
16
NP
13
10
11
NP
PIPLLLBoring ID Depth
B1
B2
B3
B3
61.6
51.3
33.4
58.6
Fines
4 - 4.5
2 - 2.9
4 - 5
14 - 15
CL
CL
SC
ML
CLAYSTONE
CLAYSTONE
CLAYEY SAND
SANDY SILT
DescriptionUSCS
CL-ML
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0.0010.010.1110100
30 40 501.5 200681014413/4 1/2 60
GRAIN SIZE IN MILLIMETERSPERCENT FINER BY WEIGHTHYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS
4 3/8 3 100 14032
GRAIN SIZE DISTRIBUTION
ASTM D422 / ASTM C136
6 16 20
1901 Sharp Point Dr Ste C
Fort Collins, CO
PROJECT NUMBER: 20215013A
SITE: West of South College Avenue and
Crestridge Drive
Fort Collins, CO
PROJECT: Fort Collins Nissan and Kia
Dealerships - Retention Pond
CLIENT: TCC Corporation
Windsor, CO
LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS-2 20215013A FORT COLLINS NISS.GPJ TERRACON_DATATEMPLATE.GDT 1/22/22SILT OR CLAY
B1
B2
B3
B3
mediumcoarsecoarsefine fineCOBBLESGRAVELSAND
CLAYSTONE (CL)
CLAYSTONE (CL)
CLAYEY SAND (SC)
SANDY SILT (ML)
31
31
27
NP
13
10
11
NP
18
21
16
NP
4 - 4.5
2 - 2.9
4 - 5
14 - 15
10.5
9.9
8.0
18.5
B1
B2
B3
B3
61.6
51.3
33.4
58.6
4 - 4.5
2 - 2.9
4 - 5
14 - 15
0.0
0.0
0.0
0.0
38.4
48.7
66.6
41.4
4.75
2
4.75
4.75
0.085
0.114
0.077
Boring ID Depth WC (%)LL PL PI Cc Cu
%Clay%Fines%Silt%Sand%Gravel Boring ID Depth D100 D60 D30 D10
USCS Classification
%Cobbles
0.0
0.0
0.0
0.0
SUPPORTING INFORMATION
Contents:
General Notes
Unified Soil Classification System
Description of Rock Properties
Note: All attachments are one page unless noted above.
Fort Collins Nissan and Kia Dealerships - Retention Pond Fort Collins, CO
Terracon Project No. 20215013A
1.00 to 2.00
Unconfined
Compressive
Strength
Qu, (tsf)
less than 0.25
0.25 to 0.50
0.50 to 1.00
2.00 to 4.00
> 4.00
Modified
California
Ring
Sampler
Standard
Penetration
Test
N
(HP)
(T)
(DCP)
UC
(PID)
(OVA)
Standard Penetration Test
Resistance (Blows/Ft.)
Hand Penetrometer
Torvane
Dynamic Cone Penetrometer
Unconfined Compressive
Strength
Photo-Ionization Detector
Organic Vapor Analyzer
SAMPLING WATER LEVEL FIELD TESTS
GENERAL NOTES
DESCRIPTION OF SYMBOLS AND ABBREVIATIONS
Water levels indicated on the soil boring logs are
the levels measured in the borehole at the times
indicated. Groundwater level variations will occur
over time. In low permeability soils, accurate
determination of groundwater levels is not possible
with short term water level observations.
Water Initially
Encountered
Water Level After a
Specified Period of Time
Water Level After
a Specified Period of Time
Cave In
Encountered
Exploration point locations as shown on the Exploration Plan and as noted on the soil boring logs in the form of Latitude and
Longitude are approximate. See Exploration and Testing Procedures in the report for the methods used to locate the
exploration points for this project. Surface elevation data annotated with +/- indicates that no actual topographical survey was
conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic
maps of the area.
LOCATION AND ELEVATION NOTES
Soil classification as noted on the soil boring logs is based Unified Soil Classification System. Where sufficient laboratory data
exist to classify the soils consistent with ASTM D2487 "Classification of Soils for Engineering Purposes" this procedure is used.
ASTM D2488 "Description and Identification of Soils (Visual-Manual Procedure)" is also used to classify the soils, particularly
where insufficient laboratory data exist to classify the soils in accordance with ASTM D2487. In addition to USCS classification,
coarse grained soils are classified on the basis of their in-place relative density, and fine-grained soils are classified on the basis
of their consistency. See "Strength Terms" table below for details. The ASTM standards noted above are for reference to
methodology in general. In some cases, variations to methods are applied as a result of local practice or professional judgment.
DESCRIPTIVE SOIL CLASSIFICATION
The soil boring logs contained within this document are intended for application to the project as described in this document.
Use of these soil boring logs for any other purpose may not be appropriate.
RELEVANCE OF SOIL BORING LOG
STRENGTH TERMS
30 - 50
> 50
Descriptive
Term
(Consistency)
8 - 15
> 30
Ring
Sampler
Blows/Ft.
10 - 29 Medium Hard
< 3
2 - 4
BEDROCK
Standard
Penetration
or N-Value
Blows/Ft.
0 - 3Very Loose Very Soft
(More than 50% retained on No. 200
sieve.)
Density determined by Standard
Penetration Resistance
(50% or more passing the No. 200 sieve.)
Consistency determined by laboratory shear strength testing,
field visual-manual procedures or standard penetration
resistance
RELATIVE DENSITY OF COARSE-GRAINED SOILS
30 - 49
50 - 79
_
6 - 10
11 - 18
19 - 36
> 36
>79
Descriptive
Term
(Consistency)
Firm
< 20 Weathered
Hard
15 - 30
Standard
Penetration or
N-Value
Blows/Ft.
0 - 1
4 - 8
Very Hard
Ring
Sampler
Blows/Ft.
Ring
Sampler
Blows/Ft.
Soft
Medium Stiff
Stiff
Very Stiff
Hard
CONSISTENCY OF FINE-GRAINED SOILS
Standard
Penetration
or N-Value
Blows/Ft.
Loose
Medium Dense
Dense
Very Dense
< 24
24 - 35
36 - 60
61 - 96
> 96
Descriptive Term
(Density)
4 - 9 20 - 29
0 - 5
6 - 14
15 - 46
47 - 79
> 80
3 - 5
UNIFIED SOIL CLASSIFICATION SYSTEM
UNIFIED SOI L CLASSI FICATI ON SYSTEM
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A
Soil Classification
Group
Symbol Group Name B
Coarse-Grained Soils:
More than 50% retained
on No. 200 sieve
Gravels:
More than 50% of
coarse fraction
retained on No. 4 sieve
Clean Gravels:
Less than 5% fines C
Cu 4 and 1 Cc 3 E GW Well-graded gravel F
Cu 4 and/or [Cc<1 or Cc>3.0] E GP Poorly graded gravel F
Gravels with Fines:
More than 12% fines C
Fines classify as ML or MH GM Silty gravel F, G, H
Fines classify as CL or CH GC Clayey gravel F, G, H
Sands:
50% or more of coarse
fraction passes No. 4
sieve
Clean Sands:
Less than 5% fines D
Cu 6 and 1 Cc 3 E SW Well-graded sand I
Cu 6 and/or [Cc<1 or Cc>3.0] E SP Poorly graded sand I
Sands with Fines:
More than 12% fines D
Fines classify as ML or MH SM Silty sand G, H, I
Fines classify as CL or CH SC Clayey sand G, H, I
Fine-Grained Soils:
50% or more passes the
No. 200 sieve
Silts and Clays:
Liquid limit less than 50
Inorganic: PI 7 and plots on or above “A”
line J
CL Lean clay K, L, M
PI 4 or plots below “A” line J ML Silt K, L, M
Organic: Liquid limit - oven dried 0.75 OL Organic clay K, L, M, N
Liquid limit - not dried Organic silt K, L, M, O
Silts and Clays:
Liquid limit 50 or more
Inorganic: PI plots on or above “A” line CH Fat clay K, L, M
PI plots below “A” line MH Elastic Silt K, L, M
Organic: Liquid limit - oven dried 0.75 OH Organic clay K, L, M, P
Liquid limit - not dried Organic silt K, L, M, Q
Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat
A Based on the material passing the 3-inch (75-mm) sieve.
B If field sample contained cobbles or boulders, or both, add “with cobbles
or boulders, or both” to group name.
C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded
gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly
graded gravel with silt, GP-GC poorly graded gravel with clay.
D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded
sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded
sand with silt, SP-SC poorly graded sand with clay.
E Cu = D60/D10 Cc =
6010
2
30
DxD
)(D
F If soil contains 15% sand, add “with sand” to group name.
G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.
H If fines are organic, add “with organic fines” to group name.
I If soil contains 15% gravel, add “with gravel” to group name.
J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.
K If soil contains 15 to 29% plus No. 200, add “with sand” or “with
gravel,” whichever is predominant.
L If soil contains 30% plus No. 200 predominantly sand, add
“sandy” to group name.
M If soil contains 30% plus No. 200, predominantly gravel, add
“gravelly” to group name.
N PI 4 and plots on or above “A” line.
O PI 4 or plots below “A” line.
P PI plots on or above “A” line.
Q PI plots below “A” line.
DESCRIPTION OF ROCK PROPERTIES
ROCK VERSION 1
WEATHERING
Term Description
Unweathered No visible sign of rock material weathering, perhaps slight discoloration on major discontinuity surfaces.
Slightly
weathered
Discoloration indicates weathering of rock material and discontinuity surfaces. All the rock material may be
discolored by weathering and may be somewhat weaker externally than in its fresh condition.
Moderately
weathered
Less than half of the rock material is decomposed and/or disintegrated to a soil. Fresh or discolored rock is
present either as a continuous framework or as corestones.
Highly
weathered
More than half of the rock material is decomposed and/or disintegrated to a soil. Fresh or discolored rock is
present either as a discontinuous framework or as corestones.
Completely
weathered All rock material is decomposed and/or disintegrated to soil. The original mass structure is still largely intact.
Residual soil All rock material is converted to soil. The mass structure and material fabric are destroyed. There is a large
change in volume, but the soil has not been significantly transported.
STRENGTH OR HARDNESS
Description Field Identification Uniaxial Compressive
Strength, psi (MPa)
Extremely weak Indented by thumbnail 40-150 (0.3-1)
Very weak Crumbles under firm blows with point of geological hammer, can be
peeled by a pocket knife 150-700 (1-5)
Weak rock Can be peeled by a pocket knife with difficulty, shallow indentations
made by firm blow with point of geological hammer 700-4,000 (5-30)
Medium strong Cannot be scraped or peeled with a pocket knife, specimen can be
fractured with single firm blow of geological hammer 4,000-7,000 (30-50)
Strong rock Specimen requires more than one blow of geological hammer to
fracture it 7,000-15,000 (50-100)
Very strong Specimen requires many blows of geological hammer to fracture it 15,000-36,000 (100-250)
Extremely strong Specimen can only be chipped with geological hammer >36,000 (>250)
DISCONTINUITY DESCRIPTION
Fracture Spacing (Joints, Faults, Other Fractures) Bedding Spacing (May Include Foliation or Banding)
Description Spacing Description Spacing
Extremely close < ¾ in (<19 mm) Laminated < ½ in (<12 mm)
Very close ¾ in – 2-1/2 in (19 - 60 mm) Very thin ½ in – 2 in (12 – 50 mm)
Close 2-1/2 in – 8 in (60 – 200 mm) Thin 2 in – 1 ft. (50 – 300 mm)
Moderate 8 in – 2 ft. (200 – 600 mm) Medium 1 ft. – 3 ft. (300 – 900 mm)
Wide 2 ft. – 6 ft. (600 mm – 2.0 m) Thick 3 ft. – 10 ft. (900 mm – 3 m)
Very Wide 6 ft. – 20 ft. (2.0 – 6 m) Massive > 10 ft. (3 m)
Discontinuity Orientation (Angle): Measure the angle of discontinuity relative to a plane perpendicular to the longitudinal axis of the
core. (For most cases, the core axis is vertical; therefore, the plane perpendicular to the core axis is horizontal.) For example, a
horizontal bedding plane would have a 0-degree angle.
ROCK QUALITY DESIGNATION (RQD) 1
Description RQD Value (%)
Very Poor 0 - 25
Poor 25 – 50
Fair 50 – 75
Good 75 – 90
Excellent 90 - 100
1. The combined length of all sound and intact core segments equal to or greater than 4 inches in length, expressed as a
percentage of the total core run length.
Reference: U.S. Department of Transportation, Federal Highway Administration, Publication No FHWA -NHI-10-034, December 2009
Technical Manual for Design and Construction of Road Tunnels – Civil Elements