HomeMy WebLinkAbout20001350.tiff GEOTECHNICAL ENGINEERING REPORT
MEADOW VALE PHASE II
PLANNED UNIT DEVELOPMENT
EAST SIDE OF WCR 51,4 NORTH OF HIGHWAY 119
WELD COUNTY, COLORADO
TERRACON PROJECT NO. 22995108
July 9, 1999
Prepared for
_ Real Estate Development Services
Mr. Floyd Oliver
4250 W. 16th Street, #46
Greeley, CO 80634
Prepared by:
Terracon
1242 Bramwood Place, Suite 2
Longmont, Colorado 80501 EXHIBR
Phone: 303-776-3921
Fax: 303-776-4041 1 '2-
2000-1350 1
lierrecon
1 Terracon
July 9, 1999 1242 Bramwood PL
Longmont,Colorado 80501
(3031776 3921 Fax_(303)776-4041
Mr. Floyd Oliver
Real Estate Development Services
4250 W. 16th Street, #46
Greeley, CO 80634
Re: Geotechnical Engineering Report
Meadow Vale Phase II - Planned Unit Development
East Side of WCR 51/2 North of Highway 119
Weld County, Colorado
Terracon Project No. 22995108
Terracon has completed geotechnical engineering exploration for the proposed Meadow
Vale Phase II residential development to be located on the east side of Weld County Road
51/2 north of Highway 119. The results of our engineering study, including the boring
location diagram, test boring records, laboratory test results and the geotechnical
recommendations needed to aid in the design and construction of foundations and other
earth connected phases of this project are attached.
In general, the subsurface soils at the site consisted of approximately six (6) to 11 feet of
man-made fill overlying gravel with silt and sand or a layer of lean clay with sand in Test
Boring 2. The fill consisted of a mixture of silty to clayey sands with some gravel and
intermittent clay lenses. Some organic material, consisting primarily of fine roots and other
vegetation, was present within the fill in some of our test borings. Sedimentary claystone
bedrock was encountered below the sands and gravels at depths ranging from about 12%
to 19 feet below the ground surface.
The results of field exploration and laboratory testing completed for this study, indicate that
the soils/bedrock at the site have variable engineering characteristics. Penetration
resistance measurements taken in the fill suggest that it was placed with some compactive
effort. In addition, we understand that the fill was placed in lifts and was compacted with
scrapers during placement. However, moisture and density testing was not performed
under the direction and observation of a geotechnical engineer and therefore some
uncertainty exists regarding the fills uniformity and engineering characteristics. Swell-
_ consolidation tests conducted on samples of the fill indicate that these materials are non-
expansive or have only slight swell potential when wetted and generally exhibit low
compressibility. The natural sands and gravels are medium dense to very dense in terms of
relative density and are considered to have moderate to high load bearing capability. We
judge the bedrock to have low swell potential and high load bearing capability.
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Quality Engineering Since 1965
Geotechnical Engineering Exploration
Mr. Floyd Oliver
Terracon Project No. 22995108
Based on the geotechnical engineering analyses, subsurface exploration and laboratory
test results, we have evaluated two (2) foundation systems which could be considered for
support of the proposed residences. These include spread footings bearing on tested and
approved structural fill or grade beams and straight shaft piers drilled into bedrock
(caissons). The use of caissons is a positive means to mitigate the risk of post-construction
settlement associated with the existing fills; however, due to the need of temporary casing
of pier holes this alternative may be costly.
Swell-consolidation tests indicate that the soils likely to influence slab-on-grade
performance are non-expansive or have only slight swell potential when wetted. Based on
these results and on our experience, we believe that slab-on-grade construction is feasible
on the site. However, the builder/owner should recognize that concrete floors constructed
on the site soils could experience some differential movement under normal loads or
should the underlying soils become wetted. Based on the Colorado Association of
Geotechnical Engineers (CAGE) criteria, the subsoils at the site are judged to have a slab
— performance risk category of"low".
Groundwater was encountered in our test borings at depths ranging from about four (4) to
eight (8) feet below the ground surface at the time of our investigation. Shallow
groundwater will limit the depth of below grade construction and in some areas, depending
upon final site grades, may preclude the use of basements. Based on current water levels
and existing grades we recommend limiting below grade construction to crawl space or
garden level construction unless the building area is elevated with fill. Other design and
construction recommendations, based upon geotechnical conditions, are presented in the
report.
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Geotechnical Engineering Exploration
Mr. Floyd Oliver
_ Terracon Project No. 22995108
We appreciate being of service to you in the geotechnical engineering phase of this
project, and are prepared to assist you during the construction phases as well. If you have
any questions concerning this report or any of our testing, inspection, design and
consulting services, please do not hesitate to contact us.
Sincerely, error**,
TERRACON Pp0 REg/
Prepared b : Reviewed0. by:
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Eric S. Willis, P.E. '��s `
s/pNALE��� � Edward J. Paas, P.E.
Senior Project Engineer uallaruiiifl" Principal
Copies to: Addressee (3)
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Geotechnical Engineering Exploration
Mr. Floyd Oliver
Terracon Project No. 22995108
TABLE OF CONTENTS
Page No.
Letter of Transmittal
INTRODUCTION 1
PROPOSED CONSTRUCTION 2
SITE EXPLORATION 2
Field Exploration 2
Laboratory Testing 3
SITE CONDITIONS 3
SUBSURFACE CONDITIONS 4
Soil and Bedrock Conditions 4
— Field and Laboratory Test Results 4
Groundwater Conditions 4
ENGINEERING ANALYSES AND RECOMMENDATIONS 5
Geotechnical Considerations 5
Foundation Systems 6
Spread Footings 6
Straight Shaft Piers 7
Basement Construction 8
Floor Slab Design and Construction 9
Pavement Design and Construction 10
Earthwork 12
General Considerations 12
Site Preparation 12
Subgrade Preparation 13
Fill Materials and Placement 13
Excavation and Trench Construction 14
Additional Design and Construction Considerations 15
Exterior Slab Design and Construction 15
Underground Utility Systems 15
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Terracon Project No. 22995108
TABLE OF CONTENTS (Cont'd)
UNDERGROUND UTILITY SYSTEMS 15
Corrosion Protection 16
Surface Drainage 16
GENERAL COMMENTS 16
APPENDIX A
Site Plan Al
Logs of Borings A2 thru A7
APPENDIX B
Swell-Consolidation Test Bl thru B7
Gradation Curves 88
"R" Value Test B9
APPENDIX C:
General Notes: Drilling & Exploration Cl
Unified Soil Classification C2
Bedrock Classification C3
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GEOTECHNICAL ENGINEERING REPORT
MEADOW VALE PHASE II
PLANNED UNIT DEVELOPMENT
EAST SIDE OF WCR 5'/2 NORTH OF HIGHWAY 119
WELD COUNTY, COLORADO
TERRACON PROJECT NO. 22995108
JULY 9, 1999
INTRODUCTION
This report contains the results of our geotechnical engineering exploration for the
proposed Meadow Vale Phase II residential development to be located on the east side of
Weld County Road 5% north of Highway 119. The site is located in the Southwest 1/4 of
Section 4, Township 2 North, Range 68 West of the 6th Principal Meridian in Weld County,
Colorado.
The purpose of these services is to provide information and geotechnical engineering
recommendations relative to:
• subsurface soil and bedrock conditions
• groundwater conditions
• foundation design and construction
• basement construction
• floor slab design and construction
• pavement design and construction
• earthwork
• drainage
The recommendations contained in this report are based upon the results of field and
laboratory testing, engineering analyses, and experience with similar soil conditions,
structures and our understanding of the proposed project.
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Terracon Project No. 22995108
PROPOSED CONSTRUCTION
We understand that the site includes approximately 8 acres and will be developed for the
construction of 14 single-family residences. We anticipate that the residences will be single
to two-story, wood frame structures with partial or full basements if feasible. Considering
the size and type of construction planned, we anticipated maximum wall and column loads
will be on the order of three (3) kips per linear foot (klf) and 40 kips, respectively. Paved
streets will be constructed to provide access to the residences. Underground utilities will
also be installed below the streets. Site grading plans were not available at the time of this
report; however, we anticipate that some earthwork will be required for surface drainage
and other development considerations. We do not envision site grading cuts or fills to
exceed about three (3) feet in depth. If actual foundation loading, type of construction or
site grading varies from those outlined above, we should be contacted to confirm and/or
modify our recommendations accordingly.
SITE EXPLORATION
The scope of the services performed for this project included site reconnaissance by a
geotechnical engineer, a subsurface exploration program, laboratory testing and
engineering analyses.
Field Exploration: A total of six (6) test borings were drilled on June 11, 1999. The
borings were drilled to depths of about 20 feet at the approximate locations shown on the
Boring Location Plan, Figure 1. All borings were advanced with a truck-mounted drilling rig,
utilizing 4-inch diameter solid stem augers. The borings were located in the field by
measurements with a surveying wheel using property boundaries and/or existing site
features as a reference. Approximate ground surface elevations at each boring location
were obtained by measurements with an engineer's level and rod. The accuracy of boring
locations and elevations should only be assumed to the level implied by the methods used
to determine each.
Continuous lithologic logs of each boring were recorded by the geotechnical engineer
during the drilling operations. At selected intervals, samples of the subsurface materials
were taken by driving split-spoon and California barrel samplers. Penetration resistance
measurements were obtained by driving the split-spoon or California barrel into the
subsurface materials with a 140-pound hammer falling 30 inches. The penetration
resistance value is a useful index in estimating the consistency, relative density or
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Terracon Project No. 22995108
hardness of the materials encountered. In addition, groundwater conditions were evaluated
in each boring at the time of site exploration, and three (3) days after completion of drilling.
Laboratory Testing: Samples retrieved during the field exploration were returned to the
laboratory for observation by the project geotechnical engineer and were visually or
manually classified in accordance with the Unified Soil Classification System described in
Appendix C. Samples of bedrock were classified in accordance with the general notes for
Bedrock Classification. At that time, the field descriptions were confirmed or modified as
necessary and an applicable laboratory testing program was formulated to determine
engineering properties of the subsurface materials. Boring logs were prepared and are
presented in Appendix A.
Laboratory tests were conducted on selected soil samples and are presented in Appendix
B. The test results were used for the geotechnical engineering analyses, and the
development of foundation and earthwork recommendations. Laboratory tests were
performed in general accordance with the applicable ASTM, local or other accepted
— standards.
Selected soil samples were tested for the following engineering properties:
• Water Content • Grain size
• Dry Density • Plasticity Index
• Swell-consolidation • R-Value
• Water Soluble Sulfate Content
SITE CONDITIONS
The project site is located on the east side of Weld County Road 5%just north of Highway
119. The site is located in or near an area which has been or is currently being used for
aggregate mining operations. Wetlands and/or marshy areas are located to the north and
south of the property while an existing lake borders the eastern boundary of the site. The
ground surface at the site is relatively uniform with a general slope downward to the north
and east. A maximum difference in elevation of approximately six (6) feet was measured
across the location of our test borings. The exception to this is the eastern edge of the
property where the ground surface slopes relatively steeply down toward the lake. Visual
observations indicate that the water level of the lake is approximately 10 feet lower in
elevation than the remainder of the site. Vegetation, where present, consisted of a sparse
to moderate growth of weeds and grasses. Other features of significance adjacent to the
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site include several other man-made lakes and the St. Vrain River which are located to the
east of the property.
SUBSURFACE CONDITIONS
Soil and Bedrock Conditions: As presented on the Logs of Boring, approximately six (6)
to 11 feet of man-made fill overlying gravel with silt and sand or a layer of lean clay with
sand in Test Boring 2. The fill consisted of a mixture of silty to clayey sands with some
gravel and intermittent clay lenses. Some organic material, consisting primarily of fine roots
and other vegetation, was present within the fill in some of our test borings. The natural
sands and gravels were encountered below the existing fill or clay layer at depths ranging
from about six (6) to 13 feet below the surface and extended to the underlying bedrock.
Sedimentary claystone bedrock was encountered below the sands and gravels at depths
ranging from about 12'/ to 19 feet below the ground surface. Please refer to the Logs of
Boring for more comprehensive strata descriptions.
— Field and Laboratory Test Results: Field penetration test results indicate that the
existing fill varies from stiff to very stiff in consistency or medium dense in terms of relative
density. Penetration resistance measurements taken in the fill suggest that it was placed
with some compactive effort. In addition, we understand that the fill was placed in lifts and
was compacted with scrapers during placement. However, moisture and density testing
was not performed under the direction and observation of a geotechnical engineer and
therefore some uncertainty exists regarding the fills uniformity and engineering
characteristics. Swell-consolidation tests conducted on samples of the fill indicate that
these materials are non-expansive or have only slight swell potential when wetted and
generally exhibit low compressibility. The natural sands and gravels are medium dense to
very dense in terms of relative density and are considered to have moderate to high load
bearing capability. We judge the bedrock to have low swell potential and high load bearing
capability.
Groundwater Conditions: Groundwater was encountered at depths of about six (6) to
eight (8) feet in the test borings at the time of field exploration. When checked three (3)
days after drilling, groundwater was measured at depths of about four (4) to eight (8) feet.
These observations represent groundwater conditions at the time of 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. Fluctuations in
groundwater levels can best be determined by implementation of a groundwater monitoring
plan. Such a plan would include installation of groundwater monitoring wells, and periodic
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Terracon Project No. 22995108
measurement of groundwater levels over a sufficient period of time. The possibility of
groundwater fluctuations should be considered when developing design and construction
plans for the project.
ENGINEERING ANALYSES AND RECOMMENDATIONS
Geotechnical Considerations: Based upon geotechnical conditions encountered in our
test borings, the site appears suitable for the proposed construction provided design and
construction recommendations outlined in this report are followed. We believe that the
primary geotechnical conditions which will influence residential construction are the shallow
groundwater and the existing fill materials encountered on the site.
As discussed previously, shallow groundwater (4 to 8 feet below the ground surface) was
encountered on the site. Shallow groundwater will limit the depth of below grade
construction and in some areas, depending upon final site grades, may preclude the use of
basements. The primary methods which can be used to mitigate the impact of shallow
groundwater on the site include limiting the depth of below grade construction (crawl
spaces or garden levels) or raising the building area with structural fill to increase the depth
to groundwater. We recommend the residences be designed so that basement floors will
be at least two (2) feet, and preferably three (3) feet, above the level of the groundwater. In
addition, grading plans should be designed so that the final street subgrade is at least
three (3) feet above the groundwater surface.
Considering the size and type of construction planned and the subsurface conditions
encountered in our test borings, we believe that two (2) foundation systems can be
considered for support of residential structures on the site. These include spread footings
bearing on tested and approved structural fill, or grade beams and straight shaft piers
drilled into bedrock (caissons). As discussed previously, penetration resistance
measurements taken in the fill suggest that it was placed with some compactive effort.
However, moisture and density testing was not performed under the direction and
observation of a geotechnical engineer and therefore some uncertainty exists regarding the
fills uniformity and engineering characteristics. We feel that the most positive foundation
options to mitigate the risk of post-construction settlement associated with the existing fills
include the use of straight shaft piers drilled into bedrock or complete removal and
recompaction of the fill below foundations. However, these alternatives may be costly
_-- because of the requirement for steel casing during pier drilling and temporary dewatering
during fill removal and replacement. We believe that with careful observation, supplemental
evaluation of the fill (additional test borings and/or field density tests) and possibly some
corrective work (removal and replacement), a portion of the existing fill could be left in
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place below foundations. It should be recognized that leaving a portion of the fill in-place
would involve some level of risk associated with post-construction settlement of the existing
fills.
Use of the recommended foundation systems and design criteria outlined in this report
should be determined for individual residential structures on the basis of supplemental
geotechnical exploration on each lot prior to construction. Supplemental exploration
methods would involve field density testing of the existing fill, observation of test pit
excavations, drilling test holes on each lot and/or observation of completed excavations
well in advance of foundation construction.
Swell-consolidation tests indicate that the soils likely to influence slab-on-grade
performance are non-expansive or have only slight swell potential when wetted. Based on
these results and on our experience, we believe that slab-on-grade construction is feasible
on the site. However, the builder/owner should recognize that concrete floors constructed
on the site soils could experience some differential movement under normal loads or
should the underlying soils become wetted. Based on the Colorado Association of
Geotechnical Engineers (CAGE) criteria, the subsoils at the site are judged to have a slab
performance risk category of"low".
Recommendations for the design and construction of foundations, foundation drainage,
floor slabs, street pavements and general earthwork requirements are discussed in the
following sections.
Foundation Recommendations
Spread Footings: If spread footings are selected for support of the proposed residence,
we recommend that field density tests be taken on the existing fill in order to determine its
suitability for foundation support. Footings may be constructed directly on the existing fill if
the density tests indicate acceptable compaction. If the tests do not meet the required
degree of compaction, at least three (3) feet of the fill will need to be removed from below
and beyond the edges of footings and replaced as a controlled structural fill. Depending
upon the depth of excavation and site specific ground water levels, it may be necessary to
dewater foundation excavations during the removal and compaction process.
Footings meeting the above criteria may be designed for a maximum soil bearing pressure
of 1,500 pounds per square foot (psf). The design bearing pressure applies to dead loads
plus design live load conditions. Exterior footings should be placed a minimum of 30 inches
below finished grade for frost protection. Interior footings should bear a minimum of 12
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Terracon Project No. 22995108
inches below finished grade. Finished grade is the lowest adjacent grade for perimeter
footings and floor level for interior footings.
Footings should be proportioned to minimize differential foundation movement.
Proportioning on the basis of relative constant dead-load pressure provides a means to
reduce differential movement between adjacent footings. Total movement of footings
designed and constructed in accordance with the above criteria is estimated to be on the
order of one (1) inch. Additional foundation movements could occur if poorly compacted fill
exists at or below proposed footings.
Foundations and walls should be reinforced as necessary to reduce the potential for
distress caused by differential foundation movement. The completed foundation excavation
should be observed by the geotechnical engineer to confirm that satisfactory bearing
materials are present and that subsurface conditions are consistent with those
encountered in our test borings. If the soil conditions encountered differ from those
presented in this report or unsuitable conditions are present, supplemental
recommendations will be required.
Straight Shaft Drilled Piers: The use of straight shaft piers is a positive means to mitigate
the risk of post-construction settlement associated with the existing fills; however, due to
the need for temporary casing of pier holes and the caving sands and gravels which will
complicate casing installation this alternative may be costly.
Straight shaft piers, drilled a minimum of four (4) feet into firm or harder bedrock are
recommended. For axial compression loads, piers may be designed for a maximum
allowable end-bearing pressure of 25,000 pounds per square foot (psf), and skin friction of
2,500 psf for the portion of the pier in the competent bedrock. All piers should be designed
to impose a dead load pressure of at least 5,000 psf based on pier end cross-sectional
area only. Where dead load requirements cannot be met, uplift resistance can be
increased by additional penetration into bedrock. Calculations for additional uplift
resistance should be based on a skin friction value of 2,500 psf for the portion of the pier in
the competent bedrock.
All piers should be reinforced full depth for the applied axial, lateral and uplift stresses
imposed. For this project, a minimum pier diameter of 16 inches is recommended to
facilitate proper cleaning, dewatering and handling of the casing. A minimum 4-inch void
space should be provided beneath the grade beam and between the piers. The void
material should be of suitable strength to support the weight of fresh concrete used in slab
_ construction and to avoid collapse when foundation backfill is placed.
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Drilling to design depth should be possible with conventional single flight power augers on
the majority of the site. Since groundwater was encountered above the level of the bedrock
and caving sand and gravel soils are present, temporary steel casing will be required to
properly drill and clean piers prior to concrete placement. We anticipate the caving sands
and gravels will complicate installation of the casing. If concrete can not be placed in
relatively dry conditions, a concrete pump truck with a tremie extension should be used to
discharge concrete at the bottom of the pier hole in order to displace excessive water. Pier
concrete should be placed immediately after completion of drilling and cleaning. Due to
potential sloughing and raveling, foundation concrete quantities may exceed calculated
geometric volumes.
Casing used for pier construction, should be withdrawn in a slow continuous manner
maintaining a sufficient head of concrete to prevent infiltration of water or the creation of
voids in pier concrete. Pier concrete should have relatively high fluidity when placed in
cased pier holes and/or through a tremie. Pier concrete with slump in the range of 5 to 7
inches is recommended. Free-fall concrete placement in piers will only be acceptable if
provisions are taken to avoid striking the concrete on the sides of the hole or reinforcing
steel. The construction of drilled piers should be observed by a representative of Terracon
in order to identify the appropriate bearing strata, observe the construction methods being
used and to confirm that subsurface conditions are consistent with those encountered in
our test borings.
Basement Construction: Groundwater was encountered in our test borings at depths
— ranging from about four (4) to eight (8) feet below the ground surface at the time of our
investigation. Shallow groundwater will limit the depth of below grade construction and in
some areas, depending upon final site grades, may preclude the use of basements. The
primary methods which can be used to mitigate the impact of shallow groundwater on the
site include limiting the depth of below grade construction (crawl spaces or garden levels)
or raising the building area with structural fill to increase the depth to groundwater. We
recommend the residences be designed so that basement floors (if used) will be at least
two (2) feet, and preferably three (3) feet, above the level of the groundwater. Since
fluctuations in the level of groundwater are possible, we recommend the provision of a
foundation drain around the lower level of the structure.
The drainage system should, at a minimum, include an underslab gravel drainage layer
sloped to an interior perimeter drainage system. The drainage system should consist of a
minimum 4-inch diameter perforated pipe, embedded in free-draining gravel, placed in a
trench at least 12-inches in width. The invert of the drain pipe should be maintained at
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Terracon Project No. 22995108
least 10-inches below the bottom of the floor slab. The trench should be inset from the
interior edge of the nearest foundation a minimum of 12-inches. In addition, for footing
foundations, the trench should be located such that an imaginary line extending downward
at a 1:1 (horizontal:vertical) slope from the bottom edge of footings does not intersect the
nearest edge of the trench. Gravel should extend a minimum of 2-inches beneath the
bottom of the pipe and at least 6-inches above the top of the drain pipe. The drain pipe
and trench should be sloped at a minimum 1/8 inch per foot to a suitable outlet, such as a
sump and pump system or other suitable outlets.
The underslab drainage layer should consist of a minimum 8-inch thickness of free-draining
gravel meeting the specifications of ASTM C33, Size No. 57 or 67. Depending upon
proximity of groundwater to the basement floor, cross-connecting drainage pipes may be
required beneath the slab at regular intervals, and should discharge to the perimeter
drainage system.
We recommend the provision of a drain also be considered for proposed crawl space
areas where shallow ground water is present. Experience indicates that over a period of
time, moist conditions and possibly standing water can develop in crawl space areas. The
crawl space drain can be as simple as a shallow trench sloped to a suitable outlet. We are
available to discuss details for a crawl space drain if desired.
Basement walls should be designed for the lateral earth pressures imposed by the soil
backfill. We recommend basement walls be designed for an equivalent fluid pressure of 45
pounds per cubic foot (pcf) for the on-site soils. Fill against foundation walls should be
moisture conditioned and well compacted to reduce the settlement potential of the backfill.
Compaction of each lift adjacent to walls should be accomplished with hand-operated
tampers or other lightweight compactors. Overcompaction may cause excessive lateral
earth pressures which could result in wall movement.
Floor Slab Design and Construction: Swell-consolidation tests indicate that the soils
likely to influence slab-on-grade performance are non-expansive or have only slight swell
potential when wetted. Based on these results and on our experience, we believe that slab-
on-grade construction is feasible on the site. However, the builder/owner should recognize
that concrete floors constructed on the site soils could experience some differential
movement under normal loads or should the underlying soils become wetted. Based on the
Colorado Association of Geotechnical Engineers (CAGE) criteria, the subsoils at the site
are judged to have a slab performance risk category of "low".
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-- The following recommendations are applicable to all planned slab-on-grade construction.
These measures will not necessarily prevent slab movement if the underlying soils become
wetted, but are intended to reduce damage if movement occurs.
• Positive separations and/or isolation joints should be provided between
slabs and all foundations, columns or utility lines to allow independent
movement.
• Contraction joints should be provided in slabs to control the location and
extent of cracking in accordance with the American Concrete Institute (ACI).
Sawed or tooled joints should have a minimum depth of 25% of slab
thickness plus '/ inch.
• As a precautionary measure, we suggest a minimum 1% inch void space be
constructed above, or below non-bearing partition walls placed on the floor
slab.
• A minimum 8-inch layer of free-draining gravel should be placed beneath
basement floor slabs in conjunction with the underslab drainage system
where groundwater is located within three (3) feet of the floor.
• Floor slabs should not be constructed on frozen subgrade.
• Other design and construction considerations, as outlined in the ACI
Design Manual, Section 302.1R are recommended.
Pavement Design and Construction: As discussed previously, comparatively shallow
groundwater was encountered on the site. To reduce the impact of shallow groundwater
on pavement construction, we recommend grading plans be designed so that the final
street subgrade is at least 3 feet above the groundwater surface. Some subgrade
stabilization, may be needed prior to fill placement or pavement construction. Stabilization
techniques could include the use of soil removal and replacement with import granular
_ materials and/or geogrids or geotextiles. Chemical treatments such as lime or fly ash could
also be considered for stabilization to reduce the impact of soft/loose subgrade soils.
Design of pavements for the project have been based on the procedures outlined in the
1986 Guideline for Design of Pavement Structures by the American Association of State
Highway and Transportation Officials (AASHTO). Traffic criteria used for pavement
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Terracon Project No. 22995108
thickness designs include an equivalent 18-kip single axle load (ESAL's) per day of 10 for
local residential streets.
For flexible pavement design, a terminal serviceability index of 2.0 was utilized along with a
design life of 20 years. Using a design R-value of 14 for the on-site soils, appropriate
ESAL/day, environmental criteria and other factors, the structural numbers (SN) of the
pavement sections were determined on the basis of the 1986 AASHTO design equation.
Recommended alternatives for flexible pavements are summarized as follows:
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stv
i✓r u 16*Ksi
Local A 5+% 5%
Residential B 2 4 6
Streets C 3 8 11
The pavement sections presented herein are based, in part, on design parameters
selected by Terracon based on experience with similar projects and soils conditions.
Design parameters such as design life, terminal serviceability index, inherent reliability and
design traffic numbers may vary with specific project requirements. Variation of these
parameters may change the thickness of the pavement sections presented. Terracon is
prepared to discuss the details of these parameters and their effects on pavement design
and reevaluate pavement design as appropriate.
Aggregate base course (if used on the site) should consist of a blend of sand and gravel
which meets strict specifications for quality and gradation. Use of materials meeting
Colorado Department of Transportation (CDOT) Class 5 or 6 specifications is
recommended for base course. Aggregate base course should be placed in lifts not
exceeding six inches and should be compacted to at least 95% of the standard Proctor
maximum dry density (ASTM D698).
Asphalt concrete and/or plant-mixed bituminous base course should be composed of a
mixture of aggregate, filler and additives, if required, and approved bituminous material.
The bituminous base and/or asphalt concrete should conform to approved mix designs
stating the Marshall or Hveem properties, optimum asphalt content, job mix formula and
recommended mixing and placing temperatures. Aggregate used in plant-mixed
bituminous base course and/or asphalt concrete should meet particular gradations.
Material meeting Colorado Department of Transportation Grading C or CX specification is
recommended for asphalt concrete. Aggregate meeting Colorado Department of
11 n:\geotech\subdivision\22995108
Geotechnical Engineering Exploration
Mr. Floyd Oliver
Terracon Project No. 22995108
Transportation Grading G or C specifications is recommended for plant-mixed bituminous
base course. Mix designs should be submitted prior to construction to verify their
adequacy. Asphalt material should be placed in maximum 3-inch lifts and should be
compacted to a minimum of 95% Marshall or Hveem density (ASTM D1559) (ASTM
D1560).
The collection and diversion of surface drainage away from paved areas is critical to the
satisfactory performance of the pavement. Drainage design should provide for the removal
of water from paved areas in order to reduce the potential for wetting of the subgrade soils.
The following recommendations should be considered at minimum:
• Site grading at a minimum 2% grade away from the pavements;
• Compaction of any utility trenches for landscaped areas to the same criteria
as the pavement subgrade;
• Sealing all landscaped areas in or adjacent to pavements to minimize or
prevent moisture migration to subgrade soils;
• Placing compacted backfill against the exterior side of curb and gutter; and,
• Placing curb, gutter and/or sidewalk directly on subgrade soils without the
use of base course materials.
Earthwork:
General Considerations: The following presents recommendations for site
preparation, excavation, subgrade preparation and placement of engineered fills on
the project. All earthwork on the project should be observed and evaluated by
Terracon. The evaluation of earthwork should include observation and testing of
engineered fill, subgrade preparation, foundation bearing soils, and other
geotechnical conditions exposed during the construction of the project.
Site Preparation: Strip and remove existing vegetation, debris and other
deleterious materials from proposed building and pavement areas. All exposed
surfaces should be free of mounds and depressions which could prevent uniform
compaction.
Stripped materials consisting of vegetation and organic materials should be wasted
from the site, or used to revegetate landscaped areas or exposed slopes after
completion of grading operations. If it is necessary to dispose of organic materials
on-site, they should be placed in non-structural areas, and in fill sections not
exceeding 5 feet in height.
12 n:\geotech\subdivision\22995108
Geotechnical Engineering Exploration
Mr. Floyd Oliver
Terracon Project No. 22995108
Exposed areas which will receive fill, once properly cleared, should be scarified to a
minimum depth of 12 inches, conditioned to near optimum moisture content, and
compacted.
It is anticipated that excavations for the proposed construction can be accomplished
with conventional earthmoving equipment. Depending upon depth of excavation
and seasonal conditions, groundwater may be encountered in excavations on the
site. Pumping from sumps may be utilized to control water within excavations. Well
points may be required for significant groundwater flow, or where excavations
penetrate groundwater to a significant depth.
The stability of the subgrade may be affected by precipitation, repetitive
construction traffic or other factors. If unstable conditions develop, workability may
be improved by scarifying and drying. Overexcavation of wet zones and
replacement with granular materials may be necessary. Use of lime, fly ash, kiln
dust, cement or geotextiles could also be considered as a stabilization technique.
Laboratory evaluation is recommended to determine the effect of chemical
stabilization on subgrade soils prior to construction. Lightweight excavation
equipment may be required to reduce subgrade pumping.
The individual contractor(s) is responsible for designing and constructing stable,
temporary excavations as required to maintain stability of both the excavation sides
and bottom. All excavations should be sloped or shored in the interest of safety
following local, and federal regulations, including current OSHA excavation and
trench safety standards.
Subgrade Preparation: Foundation bearing soils should be tested and treated as
outlined in the Foundation section of this report. Subgrade soils beneath interior
and exterior slabs, and beneath pavements should be scarified, moisture
conditioned and compacted to a minimum depth of 12 inches. The moisture
content and compaction of subgrade soils should be maintained until slab or
pavement construction.
Fill Materials and Placement: Clean on-site soils or approved imported materials
may be used as fill material. Some of the existing fill soils may contain excessive
organics and if encountered, these materials should be removed and replaced with
suitable fill.
13 n:\geotech\subdivision\22995108
Geotechnical Engineering Exploration
Mr. Floyd Oliver
Terracon Project No. 22995108
Imported soils (if required) should conform to the following or be tested and
approved by the geotechnical engineer:
Percent finer by weight
Gradation JASTM C1361
6' 100
3" 70-100
No. 4 Sieve 50-100
No. 200 Sieve 35 (max)
• Liquid Limit 30 (max)
•
Plasticity Index 10 (max)
Engineered fill should be placed and compacted in horizontal lifts, using equipment
and procedures that will produce recommended moisture contents and densities
throughout the lift. Recommended compaction criteria for engineered fill materials
are as follows:
Minimum Percent
Material (ASTM D698)
Scarified subgrade soils 95
On-site and imported fill soils:
Beneath foundations 95
Beneath slabs 95
Beneath pavements 95
Miscellaneous backfill (non-structural areas) 90
On-site and imported soils should be compacted within a moisture content range of
2 percent below, to 2 percent above optimum unless modified by the project
geotechnical engineer.
Excavation and Trench Construction: Excavations into the on-site soils will
encounter a variety of conditions. These may include caving sands and
groundwater depending upon depth of excavation. The individual contractor(s)
should be made responsible for designing and constructing stable, temporary
excavations as required to maintain stability of both the excavation sides and
bottom. All excavations should be sloped or shored in the interest of safety
14 n:\geotech\subdivision\22995108
Geotechnical Engineering Exploration
Mr. Floyd Oliver
Terracon Project No. 22995108
following local, and federal regulations, including current OSHA excavation and
trench safety standards. As a safety measure, it is recommended that all vehicles
and soil piles be kept to a minimum lateral distance from the crest of the slope
equal to no less than the slope height. The exposed slope face should be
protected against the elements.
The soils to be penetrated by the proposed excavations may vary significantly
across the site. The preliminary soil classifications are based solely on the
materials encountered in widely spaced exploratory test borings. The contractor
should verify that similar conditions exist throughout the proposed area of
excavation. If different subsurface conditions are encountered at the time of
construction, the actual conditions should be evaluated to determine any excavation
modifications necessary to maintain safe conditions.
Additional Design and Construction Considerations:
Exterior Slab Design and Construction: Exterior slabs-on-grade, exterior
architectural features, and utilities founded on, or in backfill or the existing fills will
probably experience some movement due to the volume change of the soil.
Potential movement could be reduced by:
• minimizing moisture increases in the backfill
• controlling moisture-density during placement of backfill
• using designs which allow vertical movement between the exterior
features and adjoining structural elements
• placing effective control joints on relatively close centers
Underground Utility Systems: Piping should be adequately bedded for proper
load distribution. Where utilities are excavated below groundwater, temporary
dewatering will be required during excavation, pipe placement and backfilling
operations for proper construction. Utility trenches should be excavated on safe
and stable slopes in accordance with OSHA regulations as discussed above.
Backfill should consist of the on-site soils or approved imported materials. The pipe
backfill should be compacted to at least 95 percent of the standard Proctor
maximum dry density ASTM D698.
Underground piping within or near the proposed structure should be designed with
flexible couplings, so minor deviations in alignment do not result in breakage or
15 n:\geoiech\subdivision\22995108
Geotechnical Engineering Exploration
Mr. Floyd Oliver
Terracon Project No. 22995108
distress. Utility knockouts in grade beams should be oversized to accommodate
differential movements.
Corrosion Protection: We measured soluble sulfate concentrations for
representative samples of the subsoils which will likely be in contact with structural
concrete. The sulfate concentrations measured in the samples varied from 0.011 to
0.200 percent by weight. Results of soluble sulfate testing indicate that project
concrete should use ASTM Type II or I/ll Portland cement with a minimum of 15
percent Class F fly ash and a maximum water cement ratio of 0.45. Foundation
concrete should be designed for severe sulfate exposure in accordance with the
provisions of the ACI Design Manual, Section 318, Chapter 4.
Surface Drainage: Positive drainage should be provided during construction and
maintained throughout the life of the proposed project. Infiltration of water into
utility or foundation excavations must be prevented during construction. Planters
and other surface features which could retain water in areas adjacent to the building
or pavements should be sealed or eliminated. In areas where sidewalks or paving
do not immediately adjoin the structure, we recommend that protective slopes be
provided with a minimum grade of approximately 10 percent for at least 10 feet from
perimeter walls. Backfill against footings, exterior walls, and in utility and sprinkler
line trenches should be well compacted and free of all construction debris to reduce
the possibility of moisture infiltration.
Downspouts, roof drains or scuppers should discharge into splash blocks or
extensions when the ground surface beneath such features is not protected by
exterior slabs or paving. Sprinkler systems should not be installed within 5 feet of
foundation walls. Landscaped irrigation adjacent to the foundation system should
be minimized or eliminated.
GENERAL COMMENTS
Terracon should be retained to review the final design plans and specifications so
comments can be made regarding interpretation and implementation of our geotechnical
recommendations in the design and specifications. Terracon also should be retained to
provide testing and observation during excavation, grading, foundation and construction
phases of the project.
The analysis and recommendations presented in this report are based upon the data
obtained from the borings performed at the indicated locations and from other information
16 nlgeotech\subdivision\22995108
Geotechnical Engineering Exploration
Mr. Floyd Oliver
Terracon Project No. 22995108
— discussed in this report. This report does not reflect variations which may occur between
borings or across the site. The nature and extent of such variations may not become
evident until construction. If variations appear, it will be necessary to reevaluate the
recommendations of this report.
The scope of services for this project does not include either specifically or by implication
any environmental assessment of the site or identification of contaminated or hazardous
materials or conditions. If the owner is concerned about the potential for such
contamination, other studies should be undertaken.
This report has been prepared for the exclusive use of our client for specific application to
the project discussed and has been prepared in accordance with generally accepted
geotechnical engineering practices. No warranties, either express or implied, are intended
or made. In the event that changes in the nature, design, or location of the project as
outlined in this report, are planned, the conclusions and recommendations contained in this
report shall not be considered valid unless Terracon reviews the changes, and either
— _ verifies or modifies the conclusions of this report in writing.
17 n:\geotech\subdivision\22995108
•
LEGEND
APPROXIMATE Locnj- N OF rC
& rE5r PORING DRILLED ON ICI Pd. el�,B r JUNE II,1'777
J
'li Potential!.,..
'; Civic Uses ,
++'l '(l 7 cres)
Iy I r/1a(�L�? �r }
a. E
t�. /;i;, Wet
11J - ' Lands '
S ill
ly
1'11 `::,„ —)— /.4q",,:.'„,../.. ;'I !b;
40„....,.. ...? ;,;;-;.:;;;-'G li• " 1 .ei ;cm, „,/,',,,,,,;/'j IIII@@I�II1N
s / ICI'
� ,5 13 /, ,� �1,
.54 K ss -Private e('
TB-2 1 '12' ./ Trail r. I
\ " Easement lillll 'Iiil
- --------- - ----- '
10.B3 ae , .4mid" Li dill
'/ rr-s ''',,,';',',,',',;/• el III
/ acres p & Fit,,%i I
l .b7l acres`.:.' t4i.;1 iyI
`� / .fi5 acres 7 . './ Gill! :i
\/1
'/ Proposed
.47 acres
Proposed ! rB� / {II ly\\
O / I \ill,
./ '' Weld County ---� Private Lake li;C
Library Site / Parcel A hii,j'i�,�.+'''
4 x x-� ,(;III
k
X f \ / /
•
/• \+ Private Trail Easement
Weld County l( �,/,�r ; I
• Library Open Space ''1. ---7,72- ---r------: _=_- ..---= _
Parcel A XX `X ..=:-.1!_----L-...._----=.---..-x \0.
COLORADO HIGHWAY 119
100 roo zeo
FLOYD OLIVER
MEADOW VALE-PHA GE ll
EAST 31DEOFWGR 1/2,NORTl1OFIM/'/19
WELD COUNT),COLORADO
PlaiRE 1:60R/NG LOCATION PLAN
Project xanoaer, E'5W I __
Project Na 2299108
warn By: GED lIPrra ®� sreie, p,-,�,
D/AGPµ//9 MR fj[NCRAL LOCawirrplJONLY,MIDl91�rNJ/LNpry FOR�N9rIPULTA,NR/PP'nwen Lnecked By: E34V ._. _.
LOG OF BORING NO. TB-1 Page 1 of 1
OWNER/CLIENT ARCHITECT/ENGINEER
— Floyd Oliver
SITE E. Side of WCR 5 1/2 North of HWY 119 PROJECT
Weld County, Colorado Meadow Vale Phase II
SAMPLES TESTS
e Q
,.. o co O BQ >" W t". CZ�
DESCRIPTION b �. a Z IZL. `n F' „y 5 z-
u m y a m za0 .: eeGGb ,�
U 02 a z0 0 a � Z. Ok . 70 w,a
0 Approx. Surface Elev.: 94.2 ft. c a Z I}- co m o Q O in de Z.a i
— -
-
-
CI-SC CB 23/12 24 103 -1.5/500
MAN-MADE FILL, Clayey sand and sandy
clay,with silty sand interbeds and —
1 scattered gravel, mixed browns with T. 5—
, —
�--__ gray, slightly moist to wet, very 2 _
7 0 stiff/medium dense. 87.2
a —
4i):a c GW GM SS 40/12
eo
O.
°Q °
_ -
" .ai 10—
�:Q " —
o: L _
a:Q d _
°•Soa GRAVEL WITH SILT AND SAND,brown _
a:o:A to orange brown, wet, dense. —
Co o —
Qa.
Q,
d.ea SS 42/12
a:d —
15
�'� —
16.0 78.2 —
CLAYSTONE, silty, slightly sandy,blue _
gray, slightly moist to moist, very hard. SS 50/2
20.0 74.2 20 —
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 6-11-99
WL 4 6'6/11/99 Y 5'6/14/99 BORING COMPLETED 6-11-99
WL ` lierracon RIO MOBILE B-57 FOREMAN DID
WL APPROVED ESW JOB# 22995108
LOG OF BORING NO. TB-2 Page 1 of 1
OWNER/CLIENT ARCHITECT/ENGINEER
-- Floyd Oliver
SITE E. Side of WCR 5 1/2 North of HWY 119 PROJECT
Weld County, Colorado Meadow Vale Phase II
SAMPLES TESTS
a 0j 0 W HS D V(y
-1 DESCRIPTION pc W
_ < N a Z ". 2 t4 1 g �aI
a u m a zO AC Slit,Z Gym 35 < Iii`
oApprox. Surface Elev.: 98.0 ft. C a Z H a 61 0 C u e ° en —
r-
'--._ SC CB 15/12 15 106
.. MAN-MADE FILL, Intermixed clayey sand _
and sandy clay,with silty sand lenses 5 _SM CB 19/12 -
and scattered gravel, with organics,
mixed browns with dark gray, slightly� _
_. � moist to wet, stiff/medium dense. —
1 —
^— 9.0 89.0
— —
��- —CL CB 14/12 19 102 +0.4/500
>�/ 10 -
j LEAN CLAY WITH SAND, silty, _
POSSIBLE FILL, dark gray brown with
13.0 rust, micaceous,wet, stiff. 85.0
/O
Ii0:_ —
GW GM SS 50/8
.6i...,.('
GRAVEL WITH SILT AND SAND,brown 15
-/'-O- —
`nd° 16.0 to orange brown, wet, very dense. 82 p _
CLAYSTONE, silty, slightly sandy, blue _
gray, slightly moist to moist, very hard. SS 50/3
20.0 78.0 20 -
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL. BORING STARTED 6-11-99
WATER LEVEL OBSERVATIONS
BORING COMPLETED 6-11-99
WI, 4 8'6/11/99�= 8'6/14/99 Derr acon RIG DID
MOBILE B-57 FOREMAN
WL G APPROVED ESW JOB# 22995108
wL
LOG OF BORING NO. TB-3 Page 1 of 1
OWNER/CLIENT ARCHITECT/ENGINEER
Floyd Oliver
SITE E. Side of WCR 5 1/2 North of HWY 119 PROJECT
Weld County, Colorado Meadow Vale Phase II
SAMPLES TESTS
a O O >R " OW Ad Cv7
U DESCRIPTION b IA
oN y z z a F- ��.�.11 p�j� y,
x z 4O El g g t y } Izil .1 O ac. ZO`t y CC �'
UApprox. Surface Elev.: 94.0 ft. a a z E. a. m a - a Um e a cn 4—
MAN-MADE FILL, Silty sand,with sandy _SM CB 18/12 14 115 -0.5/500
i clay lenses and scattered gravel, mixed
browns with rust, slightly moist to wet, _
_-1 medium dense. _
_ --� 88.0 5 — CB 20/12
---- 6.0 p
.O:a —
;0.d
•Qa9
a.a
.4..6....;
_ • :6:° GRAVEL WITH SILT AND SAND, brown GW-GM SS 24/12
:, :'•=c to orange brown, wet, medium dense. 10
Q'd —
Q:d° —
:4:4 _
_
.I.?.:4419 12.5 81.5
-- — SS 50/11
15
CLAYSTONE, silty, slightly sandy,blue _
gray, slightly moist to moist, hard to —
very hard. —
•
SS 50/5
20.0 74.0 —
BOTTOM OF BORING 20
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL.
_ WATER LEVEL OBSERVATIONS BORING STARTED 6-11-99
WL 4 6'6/11/99 1 4'6/14/99 BORING COMPLETED 6-11-99
WL ` 1 [err acon RIG MOBILE B-57 FGREMAN DJD
WL APPROVED ESW JOB# 22995108
LOG OF BORING NO. TB-4 Page 1 of 1
OWNER/CLIENT ARCHITECT/ENGINEER
-- Floyd Oliver
SITE E. Side of WCR 5 1/2 North of HWY 119 PROJECT
Weld County, Colorado Meadow Vale Phase II
SAMPLES TESTS
R O
` N
m U LY C III
• y��
U DESCRIPTION ya� F V7 N z ti e5
( y �7 tsl z (7 Sy .�
S m �yj F G 8 a.2 U A .1
CD Approx. Surface Elev.: 99.4 ft. Ezi
0 0 Z f a. co co 2 o a uu y d
-
SC SM 'CB 18/12 10 120 -0.6/50(
MAN-MADE FILL, Clayey sand and silty 5_
.,-.`
sand, with sandy clay lenses and —
scattered gravel, mixed browns with gra —
�_ —
and rusty, trace organics, slightly moist ' —
to wet, medium dense/very stiff. CL CB 25/12
---_-_ -
- �� —
10-
'- 11.0 88.4 —
za: —
:0. .
R:Q.4 —
'c ii —
Da.
— ": :° OW-GM CB 28/12
Q'-. 15
•0,-,0.e GRAVEL WITH SILT AND SAND,brown —
`Q..:dc to orange brown,wet, medium dense. -
- :Qs:a -
-
—
:44. —
d:4
-
O:4).e 19.0 80.4 -
20.0 CLAYSTONE, silty, slightly sandy, blue 79.4 — SS 50/10
gray, slightly moist to moist,hard. / 20
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL.
_ WATER LEVEL OBSERVATIONS BORING STARTED 6-11-99
WL SZ 6.5'Wci 6/11/99 I 7'Wci 6/14/99 BORING COMPLETED 6-11-99
WL 4 i err acon RIG MOBILE B-57 FOREMAN DJD
WL APPROVED ESW JOB# 22995108
LOG OF BORING NO. TB-5 Page 1 of 1
OWNER/CLIENT ARCHITECT/ENGINEER
Floyd Oliver
SITE E. Side of WCR 5 1/2 North of HWY 119 PROJECT
Weld County, Colorado Meadow Vale Phase II
SAMPLES TESTS
rh
O O W
DESCRIPTION ,� < a co Z "F pI I c
pCmix m m F 0 Z C O 2 g .7
a 2 ' ZO O C ZOZy C+IU ` pt.d
U a
Approx. Surface Elev.: 95.8 ft. c '6) z F PL' A 82 u N ;,5A i 5 I:
MAN-MADE FILL,Sandy lean clay, with _CL CB 18/12 13 113 +0.2/500
silty sand interbeds and scattered gravel,
mixed browns with dark gray, organics,
slightly moist to wet, very stiff. = 5=
2 —
7.0 88.8
CB 27/12
o: 10—
k
GRAVEL WITH SILT AND SAND,brown
to orange brown, wet, medium dense. —
,Q
SS 16/12
d.� 15
0:
Qk
a :p 18.0 77.8 -
-
_ 96
= = CLAYSTONE, silty, slightly sandy, blue SS 50/4
ap 20.0 gray, slightly moist to moist, very hard. 75'8 20
BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 6-11-99
WL 2 6'6/11/99 Y 5.5'6/14/99BORING COMPLETED 6-11-99
WL s 1i.err acon RIG MOBILE B-57 FOREMAN DJD
WL APPROVED ESW JOB# 22995108
LOG OF BORING NO. TB-6 Page 1 of 1
OWNER/CLIENT ARCHITECT/ENGINEER
— Floyd Oliver
SITE E. Side of WCR 5 1/2 North of HWY 119 PROJECT
Weld County, Colorado Meadow Vale Phase II
SAMPLES TESTS
a
O O Z 9E i� owa Zm
,O DESCRIPTION F ui Z 4 H N O U a
a.
✓ Approx. Surface Elev.: 98.1 ft. c 5 Z a m 2 8g °. 41 . 9� t .E
SC-SM CB 18/12 14 113 -0.4/50C
MAN-MADE FILL, Silty, clayey sand with
-
clay lenses and scattered gravel, mixed
browns with dark gray and rust,
- __
�L�viL CB 21/12 17 92 +0.1/500
, organics, slightly moist to wet, medium _
_ "� dense/very stiff to stiff. -
--__ y —
- 10.0 88.1 _CL CB 9/12
10
0: _
O d _
_ O. :' _
d n —
O'' —
d.d —
O .t
O GRAVEL WITH SILT AND SAND, brown GW-GM SS 23/12
4' to orange brown, wet, medium dense. 15
— a ' -
4 -
ad 18.0 80.1 -
CLAYSTONg, silty, slightly sandy, blue SS 50/5
7 20.0\ gray, slightly moist to moist, very hard.! 78.1 20 -
_ BOTTOM OF BORING
THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES
BETWEEN SOIL AND ROCK TYPES: IN-SITU,THE TRANSITION MAY BE GRADUAL.
WATER LEVEL OBSERVATIONS BORING STARTED 6-11-99
_
WL 8'6/11/99 = 7.5'6/14/99 1FOREMAN
4 �err acon RIG BORING COMPLETED 6-11-99
MOBILE B-57 um
WL APPROVED ESW JOB// 22995108
a---
6
4
2 :I
S
w
E i
L •
L
O
N -2
O
A 4
O
IsI
—6 f l
—8
0.1 1 10 100
APPLIED PRESSURE-KIPS PER SQUARE FT
Specimen Identification Classification DD I MC%
• TB-I 3.0 FILL; Clayey Sand and Sandy Clay; silty 103 24
PROJECT Meadow Vale Phase U- E. Side of WCR 5 JOB NO. 22995108
1/2 North HWY 119 DATE 7/6/99
SWELL/CONSOLIDATION TEST
Terracon
Longmont, Colorado
s
6 —
4
2
S
w
L —
O
N -2
O
A -4
T "
O
_6
-g
0.1 I 10 100
APPLIED PRESSURE-KIPS PER SQUARE FT
Specimen Identification Classification I DD I MC%
• TB-2 9.0 Lean Clay with Sand; silty (CL) 102 19
PROJECT Meadow Vale Phase II- E. Side of WCR 5 JOB NO. 22995108
1/2 North HWY 119 DATE 7/6/99
SWELL/CONSOLIDATION TEST
Terracon
Longmont, Colorado
S 1 ,
6 _ .
4
2
S
w
O
N -2
O
A -4
O
-6
-x
0.1 1 10 1O0
APPLIED PRESSURE-KIPS PER SQUARE FT
Specimen Identification Classification DD MC%
• TB-3 2.0 FILL. Silty Sand SM 115 14
PROJECT Meadow Vale Phase II- E. Side of WCR 5 JOB NO. 22995108
1/2 North HWY 119 DATE 7/6/99
SWELL/CONSOLIDATION TEST
Terracon
Longmont, Colorado
8
6 - -
4
2
S
O
N -2 •
O
- � D
A 4
O
-6
-8
0.1 1 10 100
APPLIED PRESSURE-KIPS PER SQUARE FT
Specimen Identification Classification DD MC%
• TB-4 3.0 FILL; Clayey Sand; silty (SC) 120 10
PROJECT Meadow Vale Phase II-E. Side of WCR 5 JOB NO. 22995108
1/2 North HWY 119 DATE 7/6/99
SWELL/CONSOLIDATION TEST
Terracon
Longmont, Colorado
8
6
4
2
- S
w
O
N
O
A -4
O
-6
-8
0.1 1
10 100
APPLIED PRESSURE-KIPS PER SQUARE FT
Specimen Identification Classification DD MC%
• TB-5 3.0 FILL; Sandy Lean Clay; silty (CL) 113 13
PROJECT Meadow Vale Phase II-E. Side of WCR 5 JOB NO. 22995108
1/2 North HWY 119 DATE 7/6/99
SWELL/CONSOLIDATION TEST
Terracon
Longmont, Colorado
R
6 - - _ _ _
4
2 -
_ S
w
E
O
N -2
O
{
A -q r
O
-6 -
-8 -
0.1 1 10 100
APPLIED PRESSURE-KIPS PER SQUARE FT
Specimen Identification Classification DD MC%
• TB-6 2.0 FILL; Silty to Clayey Sand (SC-SM) 113 14
PROJECT Meadow Vale Phase II -E. Side of WCR 5 JOB NO. 22995108
1/2 North HWY 119 DATE 7/6/99
SWELL/CONSOLIDATION TEST
Terracon
Longmont, Colorado
8 .
6 - - -
4-
2
S
w
E
O
N -2
O
A _4
O
- N
-6
-8 ,
0.1 1 10 100
APPLIED PRESSURE-KIPS PER SQUARE FT
Specimen Identification Classification DD 4 MC%
• TB-6 5.0 FILL; Sandy Lean Clay; silty (CL, CL-ML) 92 17
PROJECT Meadow Vale Phase 1I - E. Side of WCR 5 JOB NO. 22995108
1/2 North HWY 119 DATE 7/6/99
SWELL/CONSOLIDATION TEST
Terracon
Longmont, Colorado
U.S.SIEVE OPENING IN It vS I U.S.SIEVE NUMBERS HYDROMETER
6 4 2 1.5 1 3 l/23/g 3 9 6 g10 1416 20 30 40 50 1001.1 X00
100 i i , 'i T li 1 l F l 11
90 '------k'-'------"sNN\
80 T I\I\'P y{ \
R 70 \
C
E
N
T 60
P
I
N
E50 '
R
B
Y 40
W
E "
I
G 30
H
T
i
20 _ .
10 1
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS
COBBLES GRAVEL SAND SILT OR CLAY
coarse I fine coarse ` medium � fine
Specimen Identification Classification MC% LL PL PI Cc Cu
• TB-1 8.0 Well Graded Gravel with Silt and Sand GW-GM NP NP NP 2.54 65.3
_ m TB-2 2.0 Clayey Sand with Gravel SC 27 20 8
A TB-3 2.0 Silty Sand SM NP NP NP
* TB-5 2.0 Sandy Lean Clay CL 28 20 8
Snecimen Identification D100 D60 D30 D10 %Gravel %Sand %Silt %Clay
• TB-1 8.0 75.00 10.40 2.052 0.1593 56.9 34.1 9.0
m TB-2 2.0 25.00 1.87 0.122 26.7 50.0 23.3
A TB-3 2.0 19.00 0.15 6.6 52.8 40.6
* TB-5 2.0 4.75 0.11 0.0 48.9 51.1
_ PROJECT Meadow Vale Phase II-E. Side of WCR 5 JOB NO. 22995108
1/2 North HWY 119 DATE 7/6/99
GRADATION CURVES
Terracon
Longmont, Colorado
01irerracon P.O North 3 Street
P.O.Box 503
FORT COLLINS,COLORADO 80521
(970)484-0359 FAX(970)484-0454
kRES1STANCE R-VALUE' & EXPANSION
'' PRESSURE OP COMPACTE3D 501E
4
f. 33} 33,
h„lhl - :IPASTIVI, D-2844 3,, , ,3
CLIENT: Floyd Oliver
PROJECT: Meadowvale Farms Phase 2
LOCATION: Test Boring 5 @ 1-4'
TERRACON NO. 22995108 CLASSIFICATION: Sandy Lean Clay (CL), silty; A-6(2)
SAMPLE;DATA;TEST RESULTS3, ..;3,
TEST SPECIMEN NO. 1 2 3
COMPACTION PRESSURE (PSI) 120 240 300
DENSITY(PCF) 107.5 113.3 114.2
MOISTURE CONTENT(%) 18.9 16.5 16.2
EXPANSION PRESSURE 0.00 0.00 0.00
HORIZONTAL PRESSURE @ 160 PSI 138 129 125
SAMPLE HEIGHT (INCHES) 2.49 2.48 2.46
EXUDATION PRESSURE (PSI) 143.2 298.3 354.0
CORRECTED R-VALUE 9.7 14.2 17.3
UNCORRECTED R-VALUE 9.7 14.2 17.3
R-VALUE @ 300 PSI EXUDATION PRESSURE = 14
100
90
80
70
w 60
a 50
CC 40
30
20
10 ■
0
0 100 200 300 400 500 600 700 800
EXUDATION PRESSURE - PSI
DRILLING AND EXPLORATION
DRILLING & SAMPLING SYMBOLS: PS : Piston Sample
_. SS : Split Spoon - 1'/e" I.D., 2" O.D., unless otherwise noted WS : Wash Sample
ST : Thin-Walled Tube - 2.5" I.D., unless otherwise noted
_. RB : Ring Barrel Sampler - 2.42" I.D., 3" 0.D. unless otherwise noted
PA : Power Auger RB : Rock Bit
HA : Hand Auger RB : Rock Sample
CB : California Barrel) - 1.94" I.D., 2.5" O.D. 85 : Pressure Meter
AS : Auger Sample PM : ress Cone
HS : Hollow Stem Auger DCWB : Wash Bore
Penetration Test: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch 0.D. split spoon, except where noted.
WATER LEVEL MEASUREMENT SYMBOLS: WS : While Sampling
WL Water Level WD : While Drilling
WCI : Wet ave i in BCR : Before Casing Removal
DCI : Dry Cave n ACR : After Casting Removal
AB : After Boring
in indicated boring logs measured
ngs at the time d. In dicated levels may reflect the location of groundwater. In low permeability
tysoils, the accurate e pervious
of groundwater
levels is not possible with only short term observations.
DESCRIPTIVE SOIL CLASSIFICATION PHYSICAL PROPERTIES OF BEDROCK
Soil Classification is based on the Unified Soil Classification DEGREE OF WEATHERING:
system and the ASTM Designations D-2487 and D-2488.
Coarse Grained Soils have more than 50% of their dry Slight Slight decomposition of parent material on
weight retained on a #200 sieve; they are described as: joints. May be color change.
boulders, cobbles, gravel or sand. Fine Grained Soils have
less than 50%of their dry weight retained on a#200 sieve; Moderate Some decomposition and color change
they are described as: clays, if they are plastic, and silts if throughout.
they are slightly plastic or non-plastic. Major constituents
may be added as modifiers and minor constituents may be High Rock highly decomposed, may be extremely
added according to the relative proportions based on grain broken.
__ size. In addition to gradation, coarse grained soils are
defined on the basis of their relative in-place density and HARDNESS AND DEGREE OF CEMENTATION:
fine grained soils on the basis of their consistency. Limestone and Dolomite:
Example: Lean clay with sand, trace gravel, stiff (CL); silty Hard Difficult to scratch with knife.
sand, trace gravel, medium dense ISM).
Moderately Can be scratched easily with knife,
CONSISTENCY OF FINE-GRAINED SOILS Hard Cannot be scratched with fingernail.
Unconfined Compressive Soft Can be scratched with fingernail.
Strength, Cu, psf Consistency
Shale, Siltstone and Claystone:
< 500 Very Soft Hard Can be scratched easily with knife, cannot
500 - 1,000 Soft be scratched with fingernail.
1,001 - 2,000 Medium
2,001 - 4,000 Stiff Moderately Can be scratched with fingernail.
_ 4,001 - 8,000 Very Stiff Hard
8,001 - 16,000 Very Hard
Soft Can be easily dented but not molded with
RELATIVE DENSITY OF COARSE-GRAINED SOILS: fingers.
N-Blowstft Relative Density
0-3 Very Loose Sandstone and Conglomerate:
4-9 Loose Well Capable of scratching a knife blade.
10-29 Medium Dense Cemented
30-49 Dense
50-80 Very Dense Cemented Can be scratched with knife.
80 + Extremely Dense
Poorly Can be broken apart easily with fingers.
Cemented
lrerracon
UNIFIED SOIL CLASSIFICATION SYSTEM
Soil Classification
Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests° Group e
Symbol Group Name
—
Coarse-Grained Gravels more than Clean Gravels Less Cu≥4 and 1 < Cc≤36 GW Well-graded ravel`
Soils more than 50% of coarse than 5% fines 9 9
50% retained on fraction retained on
No. 200 sieve No. 4 sieve Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravel`
Gravels with Fines Fines classify as ML or MH
more than 12% finest GM Silty gravel,G,H
Fines classify as CL or CH GC Clayey graver"
Sands 50% or more Clean Sands Less Cu≥6 and 1 < Cc≤3` SW Well-graded sand'
of coarse fraction than 5% fines`
passes No. 4 sieve Cu < 6 and/or 1 > Cc > 3` SP Poorly graded sand'
Sands with Fines Fines classify as ML or MH SM Silty sand"'
more than 12% fines°
Fines Classify as CL or CH SC Clayey sand""'
Fine-Grained Soils Silts and Clays inorganic PI > 7 and plots on or above "A line' CL Lean clay"
50% or more Liquid limit less
passes the than 50 PI < 4 or plots below "A" line' ML Silt".m
No. 200 sieve
organic Liquid limit -oven dried Organic clay."."
< 0.75 OL
- Liquid limit -not dried Organic silt".""
Silts and Clays inorganic PI plots on or above "A" line CH Fat clay""'"
Liquid limit 50
or more PI lots below "A" line MH Elastic Silt"""
organic Liquid limit -oven dried Organic clayK""
< 0.75 OH
Liquid limit -not dried Organic silt"L'".°
Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat
ABased on the material passing the 3-in. r� "If soil contains 15 to 29% plus No. 200, add
175-mm) sieve a (D�)a "with sand" or "with gravel", whichever is
"1f field sample contained cobbles or Cu=D€U ID CC - Elm x Dm predominant.
-- boulders, or both, add "with cobbles or `If soil contains > 30% plus No. 200
boulders, or both" to group name. predominantly sand, add "sandy" to group
`Gravels with 5 to 12% fines require dual Flf soil contains > 15% sand, add "with name.
symbols: sand" to group name. '"If soil contains > 30% plus No. 200,
GW-GM well-graded gravel with silt "If fines classify as CL-ML, use dual symbol predominantly gravel, add "gravelly" to group
GW-GC well-graded gravel with clay GC-GM, or SC-SM. name.
GP-GM poorly graded gravel with silt "If fines are organic, add "with organic fines" "PI > 4 and plots on or above "A" line.
GP-GC poorly graded gravel with clay to group name. °Pl < 4 or plots below "A" line.
°Sands with 5 to 12% fines require dual 'If soil contains > 15% gravel, add "with PPI plots on or above "A" line.
symbols: gravel" to group name. °Pl plots below "A" line.
SW-SM well-graded sand with silt if Atterberg limits plot in shaded area, soil is
SW-SC well-graded sand with clay a CL-ML, silty clay.
SP-SM poorly graded sand with silt
SP-SC poorly graded sand with clay
60 1 I
am".a . �
and nne-a.vined fractionr o
C
QVe en p °_9 at LL (6 10 8�=Z `O
Z CG
v I 0\-
E. 20 OR
V
C MH OR OH
,ol
CL-ML ML OR OL I
I
0 10 16 20 30 40 50 60 70 90 90 100 nc
LIQUID LIMIT (LL)
llerracon
ROCK CLASSIFICATION
(Based on ASTM C-294)
Sedimentary Rocks
Sedimentary rocks are stratified materials laid down by water or wind. The sediments may be
composed of particles of pre-existing rocks derived by mechanical weathering, evaporation or by
chemical or organic origin. The sediments are usually indurated by cementation or compaction.
Chert Very fine-grained siliceous rock composed of micro-crystalline or crypto-
crystalline quartz, chalcedony or opal. Chert is various colored, porous to
dense, hard and has a conchoidal to splintery fracture.
Claystone Fine-grained rock composed of or derived by erosion of silts and clays or any
rock containing clay. Soft massive; gray, black, brown, reddish or green and
may contain carbonate minerals.
Conglomerate Rock consisting of a considerable amount of rounded gravel, sand and cobbles
with or without interstitial or cementing material. The cementing or interstitial
material may be quartz, opal, calcite, dolomite, clay, iron oxides or other
materials.
Dolomite A fine-grained carbonate rock consisting of the mineral dolomite [CaMg
(CO3121. May contain noncarbonate impurities such as quartz, chert, clay
minerals, organic matter, gypsum and sulfides. Reacts with hydrochloric acid
(HCL).
Limestone A fine-grained carbonate rock consisting of the mineral calcite (CaCo3). May
_ contain noncarbonate impurities such as quartz, chert, clay minerals, organic
matter, gypsum and sulfides. Reacts with hydrochloric acid (HCL).
Sandstone Rock consisting of particles of sand with or without interstitial and cementing
materials. The cementing or interstitial material may be quartz, opal, calcite,
dolomite, clay, iron oxides or other material.
Shale Fine-grained rock composed of, or derived by erosion of silts and clays or any
rock containing clay. Shale is hard, platy, or fissile may be gray, black,
reddish or green and may contain some carbonate minerals (calcareous shale).
Siltstone Fine grained rock composed of, or derived by erosion of silts or rock
containing silt. Siltstones consist predominantly of silt sized particles (0.0625
to 0.002 mm in diameter) and are intermediate rocks between claystones and
sandstones, may be gray, black, brown, reddish or green and may contain
carbonate minerals.
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