HomeMy WebLinkAboutOLD TOWN FLATS - PDP - PDP130022 - SUBMITTAL DOCUMENTS - ROUND 1 - RECOMMENDATION/REPORTSUBSURFACE EXPLORATION REPORT
BLOCK 23 – PHASE I
FORT COLLINS, COLORADO
EEC PROJECT NO. 1132055
Prepared for:
Brinkman Partners
3003 East Harmony Road, Suite 300
Fort Collins, Colorado 80528
Attn: Mr. Dave Derbes (dave.derbes@brinkmanpartners.com)
Prepared by:
Earth Engineering Consultants, LLC
4396 Greenfield Drive
Windsor, Colorado 80550
4396 GREENFIELD DRIVE
WINDSOR, COLORADO 80550
(970) 545-3908 FAX (970) 663-0282
EARTH ENGINEERING
CONSULTANTS, LLC
July 30, 2013
Brinkman Partners
3003 East Harmony Road - Suite 300
Fort Collins, Colorado 80528
Attn: Mr. Dave Derbes (dave.derbes@brinkmanpartners.com)
Re: Subsurface Exploration Report
Block 23 – Phase I
Fort Collins, Colorado
EEC Project No. 1132055
Mr. Derbes:
Enclosed herewith, are the results of the subsurface exploration completed by Earth Engineering
Consultants, LLC for the referenced project. As a part of a previous exploration on the Block 23
site, twelve (12) soil borings were drilled on August 14 and 15, 2008 to develop information on
subsurface conditions. Seven (7) of the site borings were in the general area of the presently
proposed Phase I area. Those borings were extended to approximate depths of 15 to 50-feet
below existing site grades. This report is based on the data developed from the borings
completed in 2008.
We understand this project involves the construction of a predominately residential building with
mixed used office and retail development on the at-grade level. Drive and parking will cover the
remainder of the lot and will extend below the upper level residential construction over a
majority of the building foot print. Foundation loads for the building are expected to be light to
moderate with continuous wall loads less than 4 kips per lineal foot (klf) and individual column
loads less than 200 kips. Floor loads are expected to be light. The eastern portion of the site is
currently occupied by single-story, slab-on-grade buildings, although this portion of the site is
not within the currently planned Phase 1 construction area.
In summary, a surficial of layer of gravel, asphaltic concrete, topsoil/landscape material, or
concrete was observed throughout the site at the boring locations. An approximate 2-1/2 to 4-
foot layer of fill material was encountered immediately beneath the surface materials. Native
cohesive to slightly cohesive sandy lean clay and/or clayey sand subsoils were encountered at
approximate depths of 2½ to 4 feet below site grades and extended to a fine to the coarse
granular strata below. Coarse silty sand with gravel and intermittent cobbles strata was
encountered below the cohesive zone at approximate depths of 3-1/2 to 13-feet below site grades
SUBSURFACE EXPLORATION REPORT
BLOCK 23 – PHASE I
FORT COLLINS, COLORADO
EEC PROJECT NO. 1132055
July 29, 2013
INTRODUCTION
The geotechnical subsurface exploration for the proposed 5-story residential development
with mixed use retail/office space on the ground floor planned as Phase I of the Block 23
redevelopment north of downtown Fort Collins, Colorado has been completed. The site for
the proposed development is situated within the Northeast ¼ of Section 11, Township 7
North, Range 69 West of 6th PM, Larimer County, Colorado.
As a part of a prior exploration of Block 23, EEC personnel completed twelve (12) soil
exploration borings on August 14 and 15, 2008 within the proposed development area of
Block 23. Seven (7) of those borings were within the presently planned Phase I area. Those
approximate boring locations are indicated on the attached boring location diagram and logs
of the borings within the Phase I area are included with this report. The borings were
extended to approximate depths of 15 to 50 feet below existing site grades. The eastern
portion of Block 23 is currently occupied by single-story, slab on grade buildings formerly
housing, a fast food restaurant on the northeast corner, and a tire and mechanical shop
building near the southeast portions of the site. Those buildings are not within the Phase I
development area.
We understand this project involves the construction of a predominately residential building
with mixed used office and retail on the ground floor. At grade parking will also be
developed within a portion of the overlying residential footprint as well as the remainder of
the site outside of the building footprint. The proposed Phase I building will be a 5-story,
approximate 18,500 sf footprint structure located at the northeast corner of Maple and Mason
Streets. Foundation loads for the residential/retail building are expected to be light to
moderate with continuous wall loads less than 4 kips per lineal foot (klf) and individual
column loads less than 200 kips. Floor loads are expected to be light.
The purpose of this report is to describe the subsurface conditions encountered in the test
borings, analyze and evaluate the test data and provide geotechnical recommendations
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concerning design and construction of foundations, support of floor slabs and pavements and
other earth related features for the proposed site improvements.
EXPLORATION AND TESTING PROCEDURES
The boring locations were determined and established in the field by a representative of
Earth Engineering Consultants, LLC (EEC) by pacing and estimating angles from
identifiable site features and by use of a hand held GPS unit. Ground surface elevations at
each boring location were estimated based on linear interpolation between contours
presented on the Fort Collins topographic quadrangle map, and are recorded on the boring
logs included in the Appendix of this report. The location for each boring and estimated
ground surface elevations should be considered accurate only to the degree implied by the
methods used for the field measurements. Photographs of the site, taken at the time of
drilling, are provided with this report.
A portion of the site borings were completed using a truck mounted, CME-75 drill rig and
the remaining borings were completed using a truck mounted, CME-45 drill rig. Both drill
rigs were equipped with a hydraulic head employed in drilling and sampling operations.
Borings B-1 through B-5 were advanced using 4-1/4-inch inside diameter hollow stem
augers; borings B-6 through B-12 were advanced using 4-inch nominal diameter continuous
flight augers. Samples of the subsurface materials encountered were obtained using split
barrel and California barrel sampling procedures.
In the split barrel and California barrel sampling procedures, standard sampling spoons are
advanced into the ground by means of a 140-pound hammer falling a distance of 30 inches.
The number of blows required to advance the split barrel and California barrel samplers is
recorded and is used to estimate the in-situ relative density of cohesionless soils and, to a
lesser degree of accuracy, the consistency of cohesive soils and hardness of weathered
bedrock. In the California barrel sampling procedure, relatively undisturbed samples are
obtained in removable brass liners. All samples obtained in the field were sealed and
returned to the laboratory for further examination, classification, and testing.
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Moisture content tests were completed on each of the recovered samples. Atterberg Limits
and washed sieve analysis tests were completed on selected samples to evaluate the quantity
and plasticity of fines in the subgrade samples. Swell/consolidation tests were completed to
evaluate the potential for the subgrade materials to change volume with variation in moisture
and load. Results of the outlined tests are indicated on the attached boring logs and summary
sheets. Only those boring logs and associated test data for the Phase I area are included with
this report.
As part of the testing program, all samples were examined in the laboratory by an engineer
and classified in accordance with the attached General Notes and the Unified Soil
Classification System, based on the soil’s texture and plasticity. The estimated group
symbol for the Unified Soil Classification System is indicated on the boring logs and a brief
description of that classification system is included with this report. Classification of the
bedrock was based on visual and tactual observation of disturbed samples and auger cuttings.
Coring and/or petrographic analysis may reveal other rock types.
SITE AND SUBSURFACE CONDITIONS
The Block 23 parcel is located on the north side of Maple Street, west of North College
Avenue, south of Cherry Street and east of Mason Street, north of downtown Fort Collins.
As shown on the enclosed site plan, the BNSF railroad tracks run through the property near
the northwest corner of the site and continues along the western boundary, parallel to North
Mason Street. Existing single-story, slab-on-grade buildings currently occupy portions of
the east half of the Block 23 site. Those buildings are outside of the Phase I area.
A surficial of layer of gravel, asphaltic concrete, topsoil/landscape material, or concrete was
observed at the boring locations. An approximate 2½ to 4-foot layer of fill material was
encountered immediately beneath the surface materials at the boring locations. The fill
materials consisted of sandy lean clay and/or clayey sand with trace amounts of gravel and
cinders. Native cohesive to slightly cohesive sandy lean clay and/or clayey sand soils were
encountered at approximate depths of 2½ to 4 feet below site grades and extended to fine to
the coarse granular soils. The coarse silty sand with gravel and intermittent cobbles strata
was encountered below the cohesive zone at approximate depths of 3½ to 13 feet below site
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grades and extended to the depths explored and/or to the bedrock below.
Siltstone/claystone/sandstone bedrock was encountered at depths of approximately 7 to 17
feet below present site grades and extended to maximum depths of exploration,
approximately 50 feet below site grade.
The stratification boundaries indicated on the boring logs represent the approximate
locations of changes in soil and bedrock types. In-situ, the transition of materials may be
gradual and indistinct.
The native cohesive soils exhibited low swell potential and low bearing capacity
characteristics, while the underlying fine to coarse granular soils containing varying zones
and quantities of cobble size material, were generally non expansive and exhibited moderate
load bearing characteristics. The underlying moderately hard to hard bedrock formation
exhibited low swell potential and high bearing capacity characteristics. The bedrock
consisted of intermittent cemented to well-cemented sandstone lenses at increased depths.
The bedrock materials were weathered nearer surface; however, became less weathered and
more competent with depth.
Well-cemented sandstone bedrock lenses were encountered at increased depths, as evident by
the Standard Penetration Test (SPT) results presented on the boring logs in the Appendix of
this report. The underlying bedrock formation with intermittent well-cemented sandstone
lenses SPT results ranged between 50 blows per 6-inches to 50-blows per 1-inch at increased
depths.
Existing Fill Material
Approximately 2-1/2 to 5-feet of fill material was encountered across the site, as evident in the
boring logs presented in the Appendix of this report. The fill material generally consisted of
silty sand with gravel, clayey sand with gravel and sandy lean clay with gravel. An
occasional lens of cinders was encountered within the fill material. Based upon the limited
field penetration resistance values recorded within the fill zone during our initial study, the in-
situ moisture contents, and the in-situ dry densities, in general, the fill material is not uniform.
Variations of depth, quality, and characteristics of the fill material may exist across the site
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and may not be revealed until time of construction. Additional field and laboratory testing
procedures as well as site observations will be required during construction phases to verify
consistency across each building footprint.
GROUNDWATER CONDITIONS
Observations were made while drilling and after completion of the borings to detect the
presence and depth to hydrostatic groundwater. At the time of drilling, free water was
observed in borings B-1 through B-4 and B-12 at approximate depths of 13 to 17-1/2-feet
below site grades. Groundwater was not encountered in the remaining borings to maximum
depths of exploration, approximately 15-feet. Field/hand slotted 1-1/2-inch diameter PVC
casings/piezometers were installed in borings B-1, B-4, and B-11, to allow for subsequent
groundwater measurements. When groundwater levels were measured on August 18, 2008,
free water or the presumed presence of groundwater via a wet cave in (WCI) was observed at
depths of approximately 12 to 15-feet below existing site grades.
Fluctuations in groundwater levels can occur over time depending on variations in
hydrologic conditions, and other conditions not apparent at the time of this report. Longer
term monitoring of water levels in cased wells, which are sealed from the influence of
surface water, would be required to more accurately evaluate fluctuations in groundwater
levels at the site. We have typically noted deepest groundwater levels in late winter and
shallowest groundwater levels in mid to late summer. Zones of perched and/or trapped water
can be encountered at times throughout the year in more permeable zones in the subgrade
soils. Perched groundwater should be expected in the subgrade soils immediately above the
less permeable bedrock strata.
Based upon review of U.S. Geological Survey maps (1Hillier, et al, 1983), regional
groundwater is expected to be encountered in unconsolidated alluvial deposits on the site, at
depths ranging from 10 to 20-feet below the existing ground surface.
1 Hillier, Donald E.; Schneider, Paul A., Jr.; and Hutchinson, E. Carter, 1983, Depth to Water Table (1979) in the
Boulder-Fort Collins-Greeley Area, Front Range Urban Corridor, Colorado, United States Geological Survey, Map
I-855-I.
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ANALYSIS AND RECOMMENDATIONS
General Considerations
The site appears suitable for the proposed development based on the subsurface conditions
observed at the test boring locations; however, certain precautions will be required in the
design and construction addressing the near surface variable fill, the apparent perched
groundwater conditions, the removal/excavation of cobbles at increased depths and penetration
of the underlying well cemented sandstone bedrock lenses.
Depending upon the depth of excavation, (i.e., if lower level construction is being planned for
elevator pits or mechanical areas), consideration should be given to installing an
underdrain/underslab drainage system to intercept or control groundwater from impacting the
lowest opening. Removal of large sized cobbles during excavation procedures should be
implemented to reduce the potential for point loading conditions developing on the floor slabs.
It is anticipated that excavations for the proposed construction can be accomplished with
conventional earthmoving equipment. However, excavations penetrating the well-cemented
sandstone bedrock may require the use of specialized heavy-duty equipment such as a rock
hammer or core barrel to achieve final design elevations. Consideration should be given to
obtaining a unit price for difficult excavation in the contract documents for the project.
Depending upon the depth of any lower level construction, a shoring plan will be necessary to
protect the adjacent sidewall slopes. The project design team should use the subsurface
information provided herein to properly design a mechanism for shoring protection. EEC is
available to provide supplemental design criteria or details such as but not limited to secant
piles or piers, soldier piers, or a tie-back/bracing concept.
Although evidence of fill materials beyond the depths described herein, or underground
facilities were not observed during the site reconnaissance, such features could be
encountered during construction. If unexpected fills or underground facilities are
encountered, such features should be removed and the excavation thoroughly cleaned prior
to backfill placement and/or construction.
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Swell – Consolidation Test Results
The swell-consolidation test is performed to evaluate the swell or collapse potential of soils or
bedrock to help determine foundation, floor slab and pavement design criteria. In this test,
relatively undisturbed samples obtained directly from the California barrel sampler are placed
in a laboratory apparatus and inundated with water under a predetermined load. The swell-
index is the resulting amount of swell or collapse after the inundation period expressed as a
percent of the sample’s initial thickness. Samples obtained at approximate depths of 1 to 2-feet
are generally pre-loaded at 150-psf to simulate the pavement loading conditions, while samples
obtained at the 3 to 4-foot intervals are pre-loaded at 500 psf to simulate the overburden soil
pressure. All samples are inundated with water and monitored for swell and consolidation.
After the inundation period, additional incremental loads are applied to evaluate the swell
pressure and consolidation.
Within the Phase I area of this site, we conducted four (4) swell-consolidation tests at various
intervals/depths. The swell index values for the samples analyzed revealed low swell
characteristics on the order of (+) 0.0 to (+) 0.9%.
Colorado Association of Geotechnical Engineers (CAGE) uses the following information to
provide uniformity in terminology between geotechnical engineers to provide a relative
correlation of slab performance risk to measured swell. “The representative percent swell
values are not necessarily measured values; rather, they are a judgment of the swell of the soil
and/or bedrock profile likely to influence slab performance.” Geotechnical engineers use this
information to also evaluate the swell potential risks for foundation performance based on the
risk categories.
Recommended Representative Swell Potential Descriptions and Corresponding
Slab Performance Risk Categories
Slab Performance Risk
Category
Representative Percent Swell
(500 psf Surcharge)
Representative Percent Swell
(1000 psf Surcharge)
Low 0 to < 3 0 < 2
Moderate 3 to < 5 2 to < 4
High 5 to < 8 4 to < 6
Very High > 8 > 6
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Based on the laboratory test results, the soil and bedrock samples analyzed for this project
generally were within the low range.
Site Preparation
Although final site grades were not available at the time of this report, based on our
understanding of the proposed development, we expect small cuts and/or fills, less than 2
feet, would be required to achieve pavement subgrade and finished floor elevations. After
removal of all existing pavements and observable surface improvements, an
extensive/thorough evaluation of the existing on-site fill material should be completed. That
evaluation should include thorough proofrolling of the exposed subgrade to help locate any
soft or loose zones in the near surface in-place materials. Prior to placement of any fill or
site improvements, we recommend the exposed soils be scarified to a minimum depth of 12
inches, adjusted in moisture content to within ±2% of standard Proctor optimum moisture
content and compacted to at least 95% of the material's standard Proctor maximum dry
density as determined in accordance with ASTM Specification D698. If excavations extend
to the underlying cemented sandstone bedrock, scarification and recompacting is not
necessary.
With the potential soft/compressible characteristics of native cohesive to slightly cohesive
clay/clayey sand soils across the site, ground stabilization mechanism may be necessary to
create a working platform for construction equipment for overlying floor construction if site
excavations extend to the cohesive materials. Placement of a granular material, such as a 3-
inch minus recycled concrete or equivalent, may be necessary as a subgrade enhancement
layer embedded into the soft soils, prior to placement of additional fill material or operating
heavy earth-moving equipment. Removal and replacement of the soft/compressible soils
could also be considered. Supplemental recommendations can be provided upon request.
Fill soils required for developing the building and site subgrades, after the initial zone has
been stabilized, should consist of approved, low-volume-change materials, which are free
from organic matter and debris. We recommend approved imported structural fill materials
be placed and compacted within the building footprint(s) and consist of essentially granular
soils with less than 20% material passing the No. 200 sieve. Beneath at grade level floor
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slabs for the residential/retail areas, we recommend a minimum 2-foot layer of structural fill
material be placed and compacted to reduce potential differential movement across the
building footprint due to the variations of the on-site subsoils. In our opinion, with close
observation/evaluation of the subgrades in the pavement areas, that structural fill zone could
be eliminated as long as the in-place subgrades appear to be stable. We recommend site fill
material be placed in loose lifts not to exceed 9 inches thick, adjusted in moisture content, to
±2% of optimum moisture content, and compacted to at least 95% of the materials maximum
dry density as determined in accordance with ASTM Specification D698, the standard
Proctor procedure. The moisture content of granular structural fill in the floor areas should
be adjusted in moisture to ±3% of optimum and compacted to at least ±95% of standard
Proctor.
Care should be exercised after preparation of the subgrades to avoid disturbing the subgrade
materials. Positive drainage should be developed away from the structures to avoid wetting
of subgrade materials. Subgrade materials becoming wet subsequent to construction of the
site structures can result in unacceptable performance.
In areas where excavations will extend below existing groundwater table or the perched
water surface level, placement of cleaner granular fill material would be desirable. Those
materials should be placed in lifts and compacted to at least 70% relative density.
Areas of deeper fills may experience settlement from underlying native soils and within the
placed fill materials. Settlement on the order of 1-inch or more per each 10 feet of fill depth
would be estimated. The rate of settlement will be dependent on the type of fill material
placed and construction methods. Granular soils will consolidate essentially immediately
upon placement of overlying loads. Cohesive soils will consolidate at a slower rate.
Foundation System – Drilled Piers/Caissons
Based on the maximum anticipated wall and columns loads, we recommend the proposed
structure be supported by a grade beam and straight shaft drilled pier/caisson foundation
system extending into the underlying bedrock formation. Particular attention will be required
in the construction of drilled piers due to the presence of groundwater or a perched surface
water condition.
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For axial compression loads, the drilled piers could be designed using a maximum end bearing
pressure of 35,000 pounds per square foot (psf), along with a skin-friction of 3,500 psf for the
portion of the pier extended into the underlying firm and/or harder bedrock formation. Straight
shaft piers should be drilled a minimum of 10-feet into competent or harder bedrock.
Required pier penetration should be balanced against potential uplift forces due to low
expansive characteristics of the subsoils and underlying bedrock on site. For design purposes,
the uplift force on each pier can be determined on the basis of the following equation:
Up = 20 x D
Where: Up = the uplift force in kips, and
D = the pier diameter in feet
Uplift forces on piers should be resisted by a combination of dead-load and pier penetration
below a depth of about 12-feet from ground surface and into the bearing strata.
To satisfy forces in the horizontal direction, piers may be designed for lateral loads using a
modulus of 50 tons per cubic foot (tcf) for the portion of the pier in native cohesive soils, 75 tcf
for native granular materials or engineered fill, and 400 tcf in bedrock for a pier diameter of 12
inches. The coefficient of subgrade reaction for varying pier diameters is as follows:
Pier Diameter (inches)
Coefficient of Subgrade Reaction (tons/ft3)
Essentially
Cohesive Soils
Engineered Fill or
Granular Soils Bedrock
18 33 50 267
24 25 38 200
30 20 30 160
36 17 25 133
When the lateral capacity of drilled piers is evaluated by the L-Pile (COM 624) computer
program, we recommend that internally generated load-deformation (P-Y) curves be used.
The following parameters may be used for the design of laterally loaded piers, using the L-Pile
(COM 624) computer program:
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Parameters Native Granular Soils
or Structural Fill
On-Site Overburden
Essentially Cohesive Soils Bedrock
Unit Weight of Soil (pcf) 130(1) 115(1) 125(1)
Cohesion (psf) 0 200 5000
Angle of Internal Friction (degrees) 35 15 20
Strain Corresponding to ½ Max. Principal
Stress Difference 50
--- 0.02 0.015
*Notes: 1) Use of 64 PCF below the water table
Drilling caissons to design depth should be possible with conventional heavy-duty single flight
power augers equipped with rock teeth on the majority of the site. However, areas of well-
cemented sandstone bedrock lenses may be encountered throughout the site at various depths
where specialized drilling equipment and/or rock excavating equipment may be required.
Excavation penetrating the well-cemented sandstone bedrock may require the use of
specialized heavy-duty equipment, together with rock augers and/or core barrels.
Consideration should be given to obtaining a unit price for difficult caisson excavation in the
contract documents for the project.
Due to the depth of groundwater or the presence of groundwater via perched surface water
conditions, as well as removal and/or drilling within large sized cobbles zones, maintaining
shafts may be difficult without stabilizing measures. Groundwater was encountered at
approximate depths of 12 to 15-feet below site grades in boring B-1 through B-4; however
perched surface water may be encountered at the bedrock interface. Therefore temporary
casing may be required to adequately/properly drill and clean piers prior to concrete
placement. Groundwater should be removed from each pier hole prior to concrete placement.
Pier concrete should be placed immediately after completion of drilling and cleaning.
A maximum 3-inch depth of groundwater is acceptable in each pier prior to concrete
placement. If pier concrete cannot be placed in dry conditions, a tremie should be used for
concrete placement. Due to potential sloughing and raveling, foundation concrete quantities
may exceed calculated geometric volumes. Pier concrete with slump in the range of 6 to 8
inches is recommended. Casing used for pier construction should be withdrawn in a slow
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continuous manner maintaining a sufficient head of concrete to prevent infiltration of water or
the creation of voids in pier concrete.
Foundation excavations should be observed by the geotechnical engineer. A representative of
the geotechnical engineer should inspect the bearing surface and pier configuration. If the soil
conditions encountered differ significantly from those presented in this report, supplemental
recommendations will be required.
Seismic
The site soil conditions consist of approximately 11 to 17-feet of overburden soils overlying
moderately hard/cemented bedrock. For those site conditions, the 2006 International
Building Code indicates a Seismic Site Classification of C.
Lateral Earth Pressures
A portion of the structure may be constructed “below grade” given the anticipated final site
grades. Those structures will be subject to lateral earth pressures. Passive lateral earth
pressures may help resist the driving forces for retaining wall or other similar site structures.
Active lateral earth pressures could be used for design of structures where some movement
of the structure is anticipated, such as retaining walls. The total deflection of structures for
design with active earth pressure is estimated to be on the order of one half of one percent of
the height of the down slope side of the structure. We recommend at-rest pressures be used
for design of structures where rotation of the walls is restrained. Passive pressures and
friction between the footing and bearing soils could be used for design of resistance to
movement of retaining walls.
Coefficient values for backfill with anticipated types of soils for calculation of active, at rest
and passive earth pressures are provided in the table below. Equivalent fluid pressure is
equal to the coefficient times the appropriate soil unit weight. Those coefficient values are
based on horizontal backfill with backfill soils consisting of essentially granular materials
with a friction angle of a 30 degrees or low volume change cohesive soils. For the at-rest
and active earth pressures, slopes away from the structure would result in reduced driving
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forces with slopes up away from the structures resulting in greater forces on the walls. The
passive resistance would be reduced with slopes away from the wall. The top 30-inches of
soil on the passive resistance side of walls could be used as a surcharge load; however,
should not be used as a part of the passive resistance value. Frictional resistance is equal to
the tangent of the friction angle times the normal force.
Soil Type Low Plasticity Cohesive Medium Dense Granular
Wet Unit Weight 115 135
Saturated Unit Weight 135 140
Friction Angle () 15° 30°
Active Pressure Coefficient 0.59 0.33
At-rest Pressure Coefficient 0.74 0.50
Passive Pressure Coefficient 1.70 3.00
Surcharge loads or point loads placed in the backfill can also create additional loads on
below grade walls. Those situations should be designed on an individual basis.
The outlined values do not include factors of safety nor allowances for hydrostatic loads.
Care should be taken to develop appropriate drainage systems behind below grade walls to
eliminate potential for hydrostatic loads developing on the walls. Those systems would
likely include perimeter drain systems extending to sump areas or free outfall where reverse
flow cannot occur into the system. Where necessary, appropriate hydrostatic load values
should be used for design.
Floor Slabs
Slab-on-grade construction is feasible for the site provided certain precautions are adhered
to. Conventional slab-on-grade construction is feasible where slabs are placed a minimum of
4 feet above the groundwater levels. If lower level “floor” slabs encroach on the minimum
4-foot separation, consideration should be given to installing an underslab drainage system.
Due to the type of construction and variability of the on-site subsoils and existing fill
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material encountered, and to reduce floor slab movement for the residential/retail areas as
presented in the “Site Preparation” of this report, we recommend the proposed floor slabs on
grade bear upon a minimum of 2 feet of properly placed and compacted imported structural
fill material, such as CDOT Class 5, 6, or 7 aggregate base course material or recycled
concrete. The approved fill material should be moisture conditioned to ±- 3% of optimum
moisture content, place in uniform 9-inch lifts and mechanically compact to at least 95% of
standard Proctor density ASTM D698. This procedure will not fully eliminate the
possibilities of slab movement; but movements should be reduced and tend to be more
uniform. We estimate the long-term movement of floor slabs with properly prepared
subgrade subsoils as outlined above would be about one-inch or less.
For structural design of concrete slabs-on-grade, a modulus of subgrade reaction of 200
pounds per cubic inch (pci) may be used for floors supported on non-expansive imported
structural fill material as previously described.
Additional floor slab design and construction recommendations are as follows:
Positive separations and/or isolation joints should be provided between slabs
and all foundations, columns or utility lines to allow independent movement.
Control joints should be provided in slabs to control the location and extent
of cracking.
Interior trench backfill placed beneath slabs should be compacted in a similar
manner as previously described for imported structural fill material.
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.
Below Grade Areas – (If Applicable)
Any below grade level construction for the site should be placed a minimum of 4-feet above
the maximum anticipate rise in groundwater. If this can not be achieved an underdrain
system should be installed to reduce the potential for hydrostatic loads to develop as well as
to control elevated groundwater levels on below grade walls and to intercept infiltration of
surface water into below grade areas.
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Other Considerations
Positive drainage should be developed away from the structure and pavement areas with a
minimum slope of 1-inch per foot for the first 10-feet away from the improvements in
landscape areas. Care should be taken in planning of landscaping, (if required), adjacent to
the building to avoid features which would pond water adjacent to the foundations or
stemwalls. Placement of plants which require irrigation systems or could result in
fluctuations of the moisture content of the subgrade material should be avoided adjacent to
site improvements. Irrigation systems should not be placed within 5 feet of the perimeter of
the building and parking areas. Spray heads should be designed not to spray water on or
immediately adjacent to the structure or site pavements. Roof drains should be designed to
discharge at least 5 feet away from the structure and away from the pavement areas.
Excavations into the on-site soils may encounter a variety of conditions. Excavations into
the on-site clays can be expected to stand on relatively steep temporary slopes during
construction. However, if excavations extend into the underlying granular strata, caving
soils may be encountered. 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 following local and federal regulations, including current OSHA excavation
and trench safety standards.
GENERAL COMMENTS
The analysis and recommendations presented in this report are based upon the data obtained
from the soil borings performed at the indicated locations and from any other information
discussed in this report. This report does not reflect any 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 evident, it will be necessary to re-evaluate the
recommendations of this report.
Earth Engineering Consultants, LLC
EEC Project No. 1132055
July 29, 2013
Page 16
It is recommended that the geotechnical engineer be retained to review the plans and
specifications so comments can be made regarding the interpretation and implementation of
our geotechnical recommendations in the design and specifications. It is further
recommended that the geotechnical engineer be retained for testing and observations during
earthwork phases to help determine that the design requirements are fulfilled. Site-specific
explorations should be completed to develop site-specific recommendations for each of the
site buildings.
This report has been prepared for the exclusive use of Brinkman Partners, for specific
application to the project discussed and has been prepared in accordance with generally
accepted geotechnical engineering practices. No warranty, express or implied, is made. In
the event that any 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 the changes are reviewed and the conclusions of this report are
modified or verified in writing by the geotechnical engineer.
DRILLING AND EXPLORATION
DRILLING & SAMPLING SYMBOLS:
SS: Split Spoon - 13/8" I.D., 2" O.D., unless otherwise noted PS: Piston Sample
ST: Thin-Walled Tube - 2" O.D., unless otherwise noted WS: Wash Sample
R: Ring Barrel Sampler - 2.42" I.D., 3" O.D. unless otherwise noted
PA: Power Auger FT: Fish Tail Bit
HA: Hand Auger RB: Rock Bit
DB: Diamond Bit = 4", N, B BS: Bulk Sample
AS: Auger Sample PM: Pressure Meter
HS: Hollow Stem Auger WB: Wash Bore
Standard "N" Penetration: Blows per foot of a 140 pound hammer falling 30 inches on a 2-inch O.D. split spoon, except where noted.
WATER LEVEL MEASUREMENT SYMBOLS:
WL : Water Level WS : While Sampling
WCI: Wet Cave in WD : While Drilling
DCI: Dry Cave in BCR: Before Casing Removal
AB : After Boring ACR: After Casting Removal
Water levels indicated on the boring logs are the levels measured in the borings at the time indicated. In pervious soils, the indicated
levels may reflect the location of ground water. In low permeability soils, the accurate determination of ground water levels is not
possible with only short term observations.
DESCRIPTIVE SOIL CLASSIFICATION
Soil Classification is based on the Unified Soil Classification
system and the ASTM Designations D-2488. Coarse Grained
Soils have move than 50% of their dry weight retained on a #200
sieve; they are described as: boulders, cobbles, gravel or sand.
Fine Grained Soils have less than 50% of their dry weight
retained on a #200 sieve; they are described as : clays, if they
are plastic, and silts if they are slightly plastic or non-plastic.
Major constituents may be added as modifiers and minor
constituents may be added according to the relative proportions
based on grain size. In addition to gradation, coarse grained
soils are defined on the basis of their relative in-place density
and fine grained soils on the basis of their consistency.
Example: Lean clay with sand, trace gravel, stiff (CL); silty
sand, trace gravel, medium dense (SM).
CONSISTENCY OF FINE-GRAINED SOILS
Unconfined Compressive
Strength, Qu, psf Consistency
< 500 Very Soft
500 - 1,000 Soft
1,001 - 2,000 Medium
2,001 - 4,000 Stiff
4,001 - 8,000 Very Stiff
8,001 - 16,000 Very Hard
RELATIVE DENSITY OF COARSE-GRAINED SOILS:
N-Blows/ft Relative Density
0-3 Very Loose
4-9 Loose
10-29 Medium Dense
30-49 Dense
50-80 Very Dense
80 + Extremely Dense
PHYSICAL PROPERTIES OF BEDROCK
DEGREE OF WEATHERING:
Slight Slight decomposition of parent material on
joints. May be color change.
Moderate Some decomposition and color change
throughout.
High Rock highly decomposed, may be extremely
broken.
HARDNESS AND DEGREE OF CEMENTATION:
BLOCK 23 DEVELOPMENT
FORT COLLINS, COLORADO
EEC PROJECT NUMBER: 1132055
AUGUST 2008
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 1000 PSF
_ _
GRAVEL AT SURFACE 1
FILL MATERIAL: _ _
CLAYEY SAND AND GRAVEL 2
black / brown _ _
CS 3 8 -- 3.3
_ _
4
SANDY LEAN CLAY (CL) _ _
brown SS 5 6 3500 10.0
stiff to very stiff _ _
6
_ _
7
_ _
8
_ _
9
_ _
SS 10 16 5000 14.8
_ _
11
_ _
12
_ _
13
SILTY SAND WITH GRAVEL (SW-SM) _ _
brown / red / gray 14
very dense _ _
SS 15 50/7" -- 2.4
_ _
16
_ _
17
SANDSTONE / CLAYSTONE / SILTSTONE _ _
brown / rust / gray 18
moderately hard to hard _ _
19
_ _
CS 20 50/5" 9000+ 15.6 40 19 -- 600 psf 0.4%
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
Continued on Sheet 2 of 2 26
Earth Engineering Consultants
FINISH DATE
FOREMAN: DG
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 1000 PSF
Continued from Sheet 1 of 2 _ _
26
SANDSTONE / CLAYSTONE / SILTSTONE _ _
brown / rust / gray, hard 27
_ _
28
_ _
29
_ _
SS 30 50/5" 9000+ 12.5
_ _
31
_ _
32
_ _
33
_ _
34
_ _
35
_ _
36
_ _
37
_ _
38
_ _
* Intermittent Well-Cemented Sandstone Lenses 39
_ _
CS 40 50/2" 9000+ 18.7 115.4
_ _
41
_ _
42
_ _
43
_ _
44
_ _
45
_ _
46
_ _
47
_ _
48
_ _
49
_ _
SS 50 50/3" 9000+ 11.8
_ _
BOTTOM OF BORING DEPTH 50.5' 51
Earth Engineering Consultants
RIG TYPE: CME45
BLOCK 23 DEVELOPMENT
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
_ _
GRAVEL AT SURFACE 1
FILL MATERIAL: _ _
CLAYEY SAND (SC) 2
black _ _
3
_ _
SANDY LEAN CLAY (CL) 4
brown _ _
stiff to very stiff CS 5 7 9000 11.8 117.4 900 psf 0.9%
_ _
6
_ _
7
_ _
8
_ _
9
_ _
SILTY SAND WITH GRAVEL (SW-SM) SS 10 50/10" -- 2.4
brown / red / gray _ _
very dense 11
_ _
12
_ _
13
_ _
14
_ _
SANDSTONE / CLAYSTONE / SILTSTONE SS 15 50/9" 1000 18.1
brown / rust / gray _ _
moderately hard to hard 16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
CS 25 50/2" 3500 17.9
_ _
Continued on Sheet 2 of 2 26
Earth Engineering Consultants
RIG TYPE: CME45
BLOCK 23 DEVELOPMENT
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
Continued from Sheet 1 of 2 _ _
26
SANDSTONE / CLAYSTONE / SILTSTONE _ _
brown / rust / gray, hard 27
_ _
28
_ _
29
_ _
30
_ _
31
_ _
32
_ _
33
_ _
34
_ _
35 -- -- --
_ _
36
_ _
37
_ _
38
_ _
39
_ _
SS 40 50/4" -- 23.9
_ _
41
_ _
*Intermittent Well Cemented Sandstone Lenses 42
_ _
43
_ _
44
gray _ _
CS 45 50/2" 8600 21.1
BOTTOM OF BORING DEPTH 44' _ _
46
_ _
47
_ _
48
_ _
49
_ _
50
_ _
51
Earth Engineering Consultants
SOIL DESCRIPTION
8/14/2008
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
_ _
GRAVEL AT SURFACE 1
FILL MATERIAL: _ _
CLAYEY SAND AND GRAVEL 2
brown / black _ _
extremely dense 3
_ _
SILTY SAND WITH GRAVEL (SW-SM) 4
brown / black _ _
extremely dense SS 5 50/3" -- 1.1
_ _
6
_ _
7
SANDSTONE / CLAYSTONE / SILTSTONE _ _
brown / rust / gray, moderately hard to hard 8
_ _
9
_ _
SS 10 50/7" 2000 13.9
_ _
11
_ _
12
_ _
13
_ _
14
_ _
CS 15 50/6" 9000+ 15.6 113.3
_ _
16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
*Intermittent Well Cemented Sandstone Lenses _ _
24
_ _
gray SS 25 50/2" -- 12.2
_ _
Continued on Sheet 2 of 2 26
Earth Engineering Consultants
FINISH DATE
FOREMAN: DG
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
Continued from Sheet 1 of 2 _ _
26
CLAYSTONE / SANDSTONE / SILTSTONE _ _
gray, hard 27
_ _
28
_ _
29
_ _
30
_ _
31
_ _
32
_ _
33
_ _
34
_ _
SS 35 50/5" 8000 14.4
_ _
36
_ _
37
_ _
38
_ _
39
_ _
CS 40 50/6" 9000+ 9.7 114.4
BOTTOM OF BORING DEPTH 40.5' _ _
41
_ _
42
_ _
43
_ _
44
_ _
45
_ _
46
_ _
47
_ _
48
_ _
49
_ _
50
_ _
51
Earth Engineering Consultants
RIG TYPE: CME45
BLOCK 23 DEVELOPMENT
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
SPARSE VEGETATION AND GRAVEL AT SURFACE _ _
FILL MATERIAL: 1
SAND AND GRAVEL _ _
brown / red / gray 2
_ _
SILTY SAND WITH GRAVEL (SW-SM) 3
brown / gray / rust _ _
dense 4
_ _
SS 5 50/10" -- 2.8
_ _
6
_ _
7
SANDSTONE / CLAYSTONE / SILTSTONE _ _
brown / rust / gray 8
moderately hard to hard _ _
9
_ _
SS 10 50/9" 8000 16.4
_ _
11
_ _
12
_ _
13
_ _
14
_ _
SS 15 50/3" 3000 16.9
_ _
BOTTOM OF BORING DEPTH 14.5' 16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
26
Earth Engineering Consultants
RIG TYPE: CME45
BLOCK 23 DEVELOPMENT
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 500 PSF
GRAVEL AT SURFACE _ _
FILL MATERIAL: 1
CLAYEY SAND (SC) _ _
black / brown 2
with scattered gravel _ _
3
SILTY SAND WITH GRAVEL (SW-SM) _ _
brown / red /gray 4
dense to very dense _ _
SS 5 50/9" -- 3.3
_ _
6
_ _
7
_ _
8
_ _
9
_ _
SANDSTONE / CLAYSTONE / SILTSTONE 10
brown / olive / rust / gray _ _
moderately hard to hard 11
_ _
12
_ _
13
_ _
14
_ _
SS 15 50/7" -- 19.8
_ _
BOTTOM OF BORING DEPTH 14.5' 16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
26
Earth Engineering Consultants
FINISH DATE
FOREMAN: DG
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 150 PSF
_ _
GRAVEL AT SURFACE 1
FILL MATERIAL: _ _
CLAYEY SAND (SC) 2
black _ _
CS 3 7 -- 10.2 87.2 <150 psf None
_ _
4
SANDY LEAN CLAY (CL) _ _
brown SS 5 5 4500 11.4
medium stiff _ _
6
_ _
7
_ _
8
SILTY SAND WITH GRAVEL (SW-SM) _ _
brown / red / gray 9
medium dense to dense _ _ -- -- 4.3
10
_ _
11
_ _
12
_ _
13
_ _
14
SANDSTONE / CLAYSTONE / SILTSTONE _ _
brown / olive / rust / gray SS 15 50/6" -- 21.3
moderately hard to hard _ _
BOTTOM OF BORING DEPTH 14.5' 16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
26
Earth Engineering Consultants
FINISH DATE
FOREMAN: DG
DATE:
AUGER TYPE: 4" CFA
SPT HAMMER: MANUAL
D N QU MC DD -200
TYPE (FEET) (BLOWS/FT) (PSF) (%) (PCF) LL PI (%) PRESSURE % @ 150 PSF
_ _
GRAVEL AT SURFACE 1
FILL MATERIAL: _ _
CLAYEY SAND with GRAVEL 2
brown _ _
3
CLAYEY SAND (SC) _ _
brown 4
medium dense to dense _ _
CS 5 8 6500 12.8 116.5 23 7 43.9 <150 psf 0.1%
_ _
6
_ _
7
_ _
8
_ _
9
_ _
10
_ _
11
_ _
12
SILTY SAND WITH GRAVEL (SW-SM) _ _
brown / red / rust 13
medium dense to dense _ _
14
SANDSTONE / CLAYSTONE / SILTSTONE _ _
brown / olive / rust / gray SS 15 50/9" -- 21.5
moderately hard to hard _ _
BOTTOM OF BORING DEPTH 14.75' 16
_ _
17
_ _
18
_ _
19
_ _
20
_ _
21
_ _
22
_ _
23
_ _
24
_ _
25
_ _
26
Earth Engineering Consultants
RIG TYPE: CME45
BLOCK 23 DEVELOPMENT
SWELL / CONSOLIDATION TEST RESULTS
%Swell @ 1000:
Project:
Project #:
Date:
Material Description: Sandstone / Claystone / Siltstone
Sample Location: Boring 2, Sample 5, Depth 19'
Liquid Limit: 40 Plasticity Index: 19 % Passing #200: - -
Beginning Moisture: 14.4% Dry Density: 116.5 psf Ending Moisture: 17.8%
Swell Pressure: 600 psf 0.4%
Block 23 Development
Fort Collins, Colorado
1082088 / 1132055
August 2008
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Water Added
Consolidation Swell
SWELL / CONSOLIDATION TEST RESULTS
% Swell @ 500:
Project:
Project #:
Date:
Material Description: Clayey Sand (SC)
Sample Location: Boring 3, Sample 1, Depth 4'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
Beginning Moisture: 9.5% Dry Density: 119.3 psf Ending Moisture: 13.3%
Swell Pressure: 900 psf 0.9%
Block 23 Development
Fort Collins, Colorado
1082088 / 1132055
August 2008
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Water Added
Consolidation Swell
SWELL / CONSOLIDATION TEST RESULTS
% Swell @ 150:
Project:
Project #:
Date:
Material Description: Clayey Sand (SC)
Sample Location: Boring 10, Sample 1, Depth 2'
Liquid Limit: - - Plasticity Index: - - % Passing #200: - -
Beginning Moisture: 10.3% Dry Density: 85.3 psf Ending Moisture: 21.0%
Swell Pressure: <150 psf None
Block 23 Development
Fort Collins, Colorado
1082088 / 1132055
August 2008
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Water Added
Consolidation Swell
SWELL / CONSOLIDATION TEST RESULTS
% Swell @ 150:
Project:
Project #:
Date:
Material Description: Sandy Lean Clay (CL)
Sample Location: Boring 11, Sample 1, Depth 4'
Liquid Limit: 23 Plasticity Index: 7 % Passing #200: 43.9%
Beginning Moisture: 12.6% Dry Density: 116.7 psf Ending Moisture: 13.7%
Swell Pressure: <150 psf 0.1%
Block 23 Development
Fort Collins, Colorado
1082088 / 1132055
August 2008
-10.0
-8.0
-6.0
-4.0
-2.0
0.0
2.0
4.0
6.0
8.0
10.0
0.01 0.1 1 10
Percent Movement
Load (TSF)
Water Added
Consolidation Swell
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-11 (PIEZOMETER)
SHEET 1 OF 1 WATER DEPTH
A-LIMITS SWELL
14.5'
N/A
WHILE DRILLING 14.5'
AFTER DRILLING
24 HOUR
START DATE
SOIL DESCRIPTION
8/14/2008
8/15/2008
4982
FOREMAN: DG
APPROX. SURFACE ELEV
FINISH DATE
SOIL DESCRIPTION
8/14/2008
8/15/2008
APPROX. SURFACE ELEV 4981
START DATE
A-LIMITS SWELL
N/A
N/A
WHILE DRILLING None
AFTER DRILLING
24 HOUR
RIG TYPE: CME45 WATER DEPTH
BLOCK 23 DEVELOPMENT
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-10
SHEET 1 OF 1
SOIL DESCRIPTION
8/14/2008
8/15/2008
APPROX. SURFACE ELEV 4983
START DATE
A-LIMITS SWELL
N/A
N/A
WHILE DRILLING None
AFTER DRILLING
24 HOUR
RIG TYPE: CME45 WATER DEPTH
BLOCK 23 DEVELOPMENT
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-6
SHEET 1 OF 1
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-5
SHEET 1 OF 1 WATER DEPTH
A-LIMITS SWELL
N/A
N/A
WHILE DRILLING None
AFTER DRILLING
24 HOUR
START DATE
SOIL DESCRIPTION
8/14/2008
8/15/2008
4982
FOREMAN: DG
APPROX. SURFACE ELEV
FINISH DATE
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-4 (PIEZOMETER)
SHEET 2 OF 2 WATER DEPTH
A-LIMITS SWELL
14.0'
N/A
WHILE DRILLING 14.5'
AFTER DRILLING
24 HOUR
START DATE
SOIL DESCRIPTION
8/14/2008
8/15/2008
4982
FOREMAN: DG
APPROX. SURFACE ELEV
FINISH DATE
SOIL DESCRIPTION
8/14/2008
8/15/2008
APPROX. SURFACE ELEV 4982
START DATE
A-LIMITS SWELL
14.0'
N/A
WHILE DRILLING 14.5'
AFTER DRILLING
24 HOUR
RIG TYPE: CME45 WATER DEPTH
BLOCK 23 DEVELOPMENT
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-4 (PIEZOMETER)
SHEET 1 OF 2
8/15/2008
4981
FOREMAN: DG
APPROX. SURFACE ELEV
FINISH DATE
START DATE WHILE DRILLING 14.0'
AFTER DRILLING
24 HOUR
A-LIMITS SWELL
N/A
N/A
RIG TYPE: CME45
BLOCK 23 DEVELOPMENT
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-3
SHEET 2 OF 2 WATER DEPTH
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-3
SHEET 1 OF 2 WATER DEPTH
A-LIMITS SWELL
N/A
N/A
WHILE DRILLING 14.0'
AFTER DRILLING
24 HOUR
START DATE
SOIL DESCRIPTION
8/14/2008
8/15/2008
4981
FOREMAN: DG
APPROX. SURFACE ELEV
FINISH DATE
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-2
SHEET 2 OF 2 WATER DEPTH
A-LIMITS SWELL
N/A
N/A
WHILE DRILLING 14.5'
AFTER DRILLING
24 HOUR
START DATE
SOIL DESCRIPTION
8/14/2008
8/15/2008
4981
FOREMAN: DG
APPROX. SURFACE ELEV
FINISH DATE
SOIL DESCRIPTION
8/14/2008
8/15/2008
APPROX. SURFACE ELEV 4981
START DATE
A-LIMITS SWELL
N/A
N/A
WHILE DRILLING 14.5'
AFTER DRILLING
24 HOUR
RIG TYPE: CME45 WATER DEPTH
BLOCK 23 DEVELOPMENT
FORT COLLINS, COLORADO
PROJECT NO: 1132055 AUGUST 2008
LOG OF BORING B-2
SHEET 1 OF 2
Limestone and Dolomite:
Hard Difficult to scratch with knife.
Moderately Can be scratched easily with knife.
Hard Cannot be scratched with fingernail.
Soft Can be scratched with fingernail.
Shale, Siltstone and Claystone:
Hard Can be scratched easily with knife, cannot be
scratched with fingernail.
Moderately Can be scratched with fingernail.
Hard
Soft Can be easily dented but not molded with
fingers.
Sandstone and Conglomerate:
Well Capable of scratching a knife blade.
Cemented
Cemented Can be scratched with knife.
Poorly Can be broken apart easily with fingers.
Cemented