HomeMy WebLinkAboutWESTFIELD PARK (STOCKBRIDGE) PUD - FINAL - 27-94A - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORT0
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Combined II ABC • RLM 6/l/70
kno`Vt(S J J
I:5 nU�v'n- evina) gravelly loam (31K2, 031K1) LRA 68
11oderately deep to deep voila with good to excellent a•.oisture holding
capacity. Air, water, and root penetration is good. Top Boils aro
loams or gravelly loam, and subsoils are gravelly clays. They generally
have underlyin4 liaxy sands, gravel, or cobbles at depths of 30 to 50
inches. Small areas. of these calcoreouo gravelo are lime cemented and
concrete -like.
Land Capability Units Soil Group 8, 12
Slope Irrigated
Group
0-3% IIIe3 Class III Irrigated Land. Care needed to prevent
B water erosion. Leveling may be limited by under-
lying gravels. Slopes leas than 3 feet in 100
feet.
IVel Class IVe Irrigated Lcnd. Bxtrc= care needed
COD to prevent water erosion. Leveling and crop
yields may be limited by depth of gravels. Best
suited to permanent vegetation. Slopes range
from 3 to 9 feet in 100 feet.
0-3 %
B
3-9%
COD
• .3
Non -Irrigated
IM61
VIe
Loamy. Plains Range Site
Class Ills Non -Irrigated Land. Clayey soils and
depth to gravel limits capability. Slopes are
less than 3 feet in 100 feet.
Class VIe Non -Irrigated Land. Severe water erosion
hazard and depth to gravels limits capability.
Best suited to permanent vegetation. Slopes
range from 3 to 9 feet in 100 feet.
D- 3
1. SOIL f" I/n�P
LE-/,E_ND
j45 _g (1fyN/�MF��I F VIN 5 % SLOPE-S.
IL5-e- UtJN/-NM(_N (SLE VIN cn) L--R/�V L� Y L1J/�M 3-% C+LOPES.
�� '/t CORNER 01- 34 -7 69
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D- 1
EMPIRE LABORATORIES, INC.
APPENDIX D.
pneumatic -tired rollers, three -wheel power rollers, vibratory compactors,
or other approved equipment well -suited to the soil being compacted. If
a sheepfoot roller is used, it shall be provided with cleaner bars
t the
mulation of
attached ina manner which Th lrollersnshouldabeudesigned so thateial
ffective
between the tamper feet.
weight can be increased.
MOISTIiRE-DENSITY DETERMINATION
Samples of representative fill materials to be placed shall be furnished
.by the contractor to the soils engineer for determination of maximum
density and optimum moisture or percent of Relative Density for these
ion
ill be made
g methods
materials. Tests for this ents ofASTMDt698,wASTM D 1557,unorASTM D 2049.
conforming to requirem
Copies of the results of these
W1ll be These testlshed to the results shallwberthehe
project engineer, and the contractor.
basis of control for all compaction effort.
DENSITY TESTS
The density and moisture content of each layer of compacted fill will be
D 1556, ASTM D
determined by the soils engineer in accordance with ASTM
2167, or ASTM D 2922. Any material found not to comply with the minimum
specified density shall be recompacted until the required density is
obtained. Sufficient density tests shall be made and submitted to
support the soils engineer's recommendations. The results of density
tests will also be furnished to the owner, the project engineer, and the
contractor by the soils engineer.
_—�— C-4
PLACING FILL
No sod, brush, frozen or thawing material, or other unsuitable material
shall be placed in the fill, and no fill shall be placed during unfavorable
weather conditions. All clods shall be broken into small pieces, and
distribution of material in the fill shall be such as to preclude the
formation of lenses of.material differing from the surrounding material.
The materials shall be delivered to and spread on the fill surface in a
manner which will result in a uniformly compacted fill. Each layer
shall be thoroughly blade mixed during spreading to insure uniformity of
material and moisture in each layer. Prior to compacting, each layer
shall have a maximum thickness of eight inches, and its upper surface
shall be approximately horizontal. Each successive 6 to 8 lift of
fill being placed on slopes or hillsides should be benched into the
existing slopes, providing good bond between the fill and existing
ground.
h10ISTURE CONTROL
While being compacted, the fill material in each layer shall as nearly
as practical contain the amount of moisture required for optimum compaction
or as specified, and the moisture shall be uniform throughout the fill.
The contractor may be required to add necessary moisture to the fill
material and to uniformly mix the water with the fill material if,. in
the opinion of the soils engineer, it is not possible to obtain uniform
moisture content by adding water on the fill surface. If, in the opinion,
of the soils engineer, the material proposed for use in the compacted
fill is too wet to permit adequate compaction, it shall be dried in an
acceptable manner prior to placement and compaction.
COMPACTION
When an acceptable, uniform moisture content is obtained, each layer
shall be compacted by a method acceptable to the soils engineer and as
specified in the foregoing report as determined by applicable standards.
Compaction shall be performed by rolling with approved tamping rollers,
APPENDIX C.
Suggested Specifications for Placement of Compacted Earth Fill
and/or Backfills.
GENERAL
A soils engineer shall be on -site to provide continuous observation
during filling and grading operations and shall be the owner's repre-
sentative to inspect placement of all compacted fill and/or backfill on
the project. The soils engineer shall approve all earth materials prior
to their use, the methods of placing, and the degree of compaction
obtained.
MATERIALS
Soils used for all compacted fill and backfill shall be approved by the
soils engineer prior to their use. The upper two (2) feet of compacted
earth backfill placed adjacent to exterior foundation walls shall be an
impervious, nonexpansive material. No material, including rock, having
a maximum dimension greater than six inches shall be placed in any fill.
Any fill containing rock should be carefully mixed to avoid nesting and
creation of voids. In no case shall frozen material be used as a fill
and/or backfill material.
PREPARATION OF SUBGRADE
All topsoil, vegetation (including trees and brush), timber, debris,
rubbish, and other unsuitable material shall be removed to a depth
satisfactory to the soils engineer and disposed of by suitable means
before beginning preparation of the subgrade. The subgrade surface of
the'area to be filled shall be scarified a minimum depth of six inches,
moistened as necessary, and compacted in a manner specified below for
the subsequent layers of fill. Fill shall not be placed on frozen or
muddy ground.
C-2
APPENDIX C.
0
c
Summary of Test Results
Atterberg Summary
1
3
7
8
13
14
Boring No.
Depth (Ft.)
1.0-2.0
3.0-4.0
1.0-2.0
3.0-4.0
3.0-4.0
2.3-3.3
Liquid Limit
30.0
21.5
34.7
20.6
24.0
36.8
Plastic Limit
15.1
15.5
17.7
13.6
16.6
19.8
Plastj.city Index
14.9
6.0
17.0
7.0
7.4
17.0
52.4
% Passing 200
42.0
28.2
43.3
25.2
24.7
5.8
Group Index
2.4
0.0
3.4
0.0
0.0
Classification
Unified
Sc
SC-SM
SC
SC-SM
SC-SM
CL
A-6(2)
A-2-4(0)
A-6(3)
A-2-4(0)
A-2-4(0)
A-6(6)
AASHTO
SUMMARY OF TEST RESULTS
BORING
NO.
DEPTH
FT.
%
MOISTURE
DRY DENSITY
P.C.F.
UNCONFINED COMPRESSIVE
STRENGTH-P.S.F.
WATER SOLUBLE
SULFATES-%,
PENETRATION
BLOWS/INCHES
10
0.5-1.5
10.4
28/12
3.0-4.0
6.7
109.7
39960
4.0-500
22/12
7.0- 8.0
15.5
110.4
49290
8.0-9.0
8/12
13.5-14.5
24.1
3/12. .
,
11
0.5-1.5
5.8
26/12
3.0-4.0
4.1
4.0-5.0
8/12
7.0-8.0
11.7
120.9
59690
8.0-9.0
18/12
13.5-14.5
17.0
4/12
• 12
0.5-1.5
10.3
32/12
3.0- 4.0
2.3
4.0-5.0
18/12 .
7.0-8.0
11.1
121.3
89670
.035 .
8.0-9.0
27/12
13.5-14.5
14.4
26/12
EMPIRE LABORATORIES, INC.
BORING
NO.
DEPTH
%
MOISTURE
7
1.0-2.0
7.0
2.0-3.0
7.0-8.0
12.0
8.0-9.0
13.5-14.5
10.9
8
0.5-1.5
10.8
3.0- 4.0
4.0
4.0-5.0
7.0-8.0
13.5
13.5-14.5
21.0
9
0.5-1.5
9.0
3.0- 4.0
5.6
'
4.0-5.0
7.0-8.0
4.1
.8.0-9.0
13.5-14.5
1.5
SUMMARY OF TEST RESULTS
DRY DENSITY UNCONFINED
STRENGTH-P.S.F. COMPRESSIVE
P.C.F.
110.3 49260
104.6 1,840
107.8 1,440
WATER SOLUBLE
SULFATES-%
.045
PENETRATION
BLOWS/INCHES
29/12
10/12
13/12
22/12
16/12
11/12
8/12
28/12
21/12
9/12
29/12
EMPIRE LABORATORIES, INC.
SUMMARY OF TEST RESULTS
DEPTH
FT.
0.5-1.5
%
MOISTURE
8.1
DRY DENSITY
P.C.F.
UNCONFINED COMPRESSIVE
STRENGTH-P.S.F.
WATER SOLUBLE
SULFATES-%
PENETRATION
BLOWS/INCHES
16/12
BCRING
NO.
4
3.0- 4.0
3.1
4.0-5.0
26/12
7.0-8.0
11.5 .
8.0-9.0
34/12
13. 5-14'. 5
6.6
14/12
5
0.5-1.5
11.9
23/12
3.0-4.0
6.0
109.8
2,760
4.0-5.0
10/12
7.0-8.0
13.7
101.2
2, 380
8.0-9.0
10/12
13.5-14.5
19.9
4/12
• 6
0.5-1.5
10.8
55/12
3.0-4.0
3.8
4.0-5.0
12/12
7.0- 8.0
2.5
8.0-9.0
16/12
13.5-14.5
13.8
8/12
I '
EMPIRE LABORATORIES, INC.
CONSOLIDATION --SWELL TEST
o.38
.37
.36
rt1
• BORING NO 3 DEPTH 7'
DRY DENSITY 119.71IF13
% MOISTURE 9.6%
I
0.1 0.5 1.0 5 1c
APPLIED PRESSURE—TONS/SQ. FT.
0.1 0.5 1.0 . a
APPLIED PRESSURE-TONS/SQ. FT.
B- 5
CAI DIDc i A0^0ATnDIFC' lKif-
CONSOLIDATION --SWELL TEST
O
t-
Q
o . 74
72
.70
.68
.66
1
BORING NO 11. DEPTH 3.0
DRY DENSITY 94.6#/Ft3
% MOISTURE 4.1 %
0.5
APPLIED PRESSURE—TONS/SQ. FT.
0.s 1.0
APPLIED PRESSURE—TONS/SQ. FT.
B- 4
EMPIRE LABORATORIES, INC.—
.60
.58
O .56
a
o . 54
.5Z
.50
.48
.46 L
0.1
1
J
4
z 6
O
a
a
8
z
O
u
10
CONSOLIDATION --SWELL TEST
BORING NO 7 DEP'
DRY DENSITY 103.4#_/Ft3
% MOISTURE 7.0%
1.0
0.5 1.0 3 10
APPLIED PRESSURE-TONS/SQ. FT.
O/3
0.1 0.5 1.0
APPLIED PRESSURE-TONS/SQ. FT.
B- 3
_- EMPIRE IARORATORIES. INC.
5
IV
i
i
.58
O .56
a
o . 54
.52
.50
.48
.46
0
2
CONSOLIDATION --SWELL TEST
BORING NO 1 DEN
DRY DENSITY 104, 7l-LFt3
% MOISTURE -A 0- 7`C
0.1 0.5
APPLIED PRESSURE-TONS/SQ. FT.
1
N�D� DE.D
0.1 0.5 1.0 5 10
APPLIED PRESSURE-TONS/SQ. FT.
D-2
APPENDIX B.
LOG OF BORINGS
5105
5100
5095
5090
A-7
EMPIRE LABORATORIES, INC.
LOG OF BORINGS
5110
5105
5100
5095
wo, 12
►r�lri
p�
�-
�.
,MA
AA
. .W MMWML7
5090-
3/12 —
5085
A- G
EMPIRE LASORATORIES, INC.
LOG OF BORINGS
5110
5105
5100
5095
509 0
Klo.-7 Ne.B
=1►
=e
i
:tip
I'
A- 5
EMPIRE LABORATORIES, INC.
5115
5110
5105
5100
5095
5090
LOG OF BORINGS
��-
2712
. •
y.
24 12
9/12
24 12
' •
i
*4
15 12
t
t 20 12
�•'<
16 12
23/12
LA
ZA
9/12
i•
d
26112
,.
A
20/12
^./.
9/12
/
9 -
1
34 12
8112
A- 4
e,L0LQ&JC- M/NP /NN I]
TEST BORING LOCATION PLAN
MMAMA"y�
H
APPROXIMATE- lomT-DUR5
SLOPE-
❑ E-CIciT Mte �,TRJCTUR�S
tsp CRE_T/�C�DUS P!E_RRE_ {ORM/�TION
�N Y+ C ORNr_R OF 34 - 7- 69
rc I ,r,flc r rn/lTu Ftrl/�I�
FL{ /N"Ni VALLt_T i Lac u�rvi�a-
A- 2
FMDIDF 1 AWWATORIFS. INC.
KEY TO BORING LOGS
TOPSOIL
�•�
GRAVEL
FILL
SAND & GRAVEL
SILT
i
SILTY SAND & GRAVEL
i�
CLAYEY SILT
v p
COBBLES
SANDY SILT
1177-1
..
SAND, GRAVEL & COBBLES
®
CLAY
®
WEATHERED BEDROCK
i
SILTY CLAY
SILTSTONE BEDROCK
SANDY CLAY
®
CLAYSTONE BEDROCK
aSAND
F
SANDSTONE BEDROCK
�•'
SILTY SAND
®
LIMESTONE
le.
CLAYEY SAND
x
P. R
GRANITE
SANDY SILTY
CLAY
ASPHALT
aSHELBY
TUBE SAMPLE
8
STANDARD PENETRATION DRIVE SAMPLER
WATER TABLE
1 %' DAYS AFTER DRILLING
i
T
HOLE CAVED
5/12 Indicates that 5 blows
of a 140 pound hammer falling 30 inches was required to penetrate 12 inches.
A- 3
euooc wnnn .Tnrsec nir
APPENDIX A.
IF
approved in writing by Empire Laboratories, Inc., the soils engineer of
record.
Every effort was made to provide comprehensive site coverage
through careful locations of the test borings, while keeping the site
investigation economically feasible. Variations in soil and groundwater
conditions between test borings ►say be encountered during construction.
In order to permit correlation between the reported subsurface conditions
and the actual conditions encountered during construction and to aid in
carrying out the plans and specifications as originally contemplated, it
is recommended that Empire Laboratories, Inc. be retained to perform
continuous construction review during the excavation and foundation
phases of the work. Empire Laboratories, Inc. assumes no responsibility
for compliance with the recommendations included in this report unless
they have been retained to perform adequate on -site construction review
during the course of construction.
u
de-icing chemicals should be composed of a more durable con-
crete using a Type II cement with low water -cement ratios and
higher air contents.
(2) Finished grade should be sloped away from the structures on
all sides to give positive drainage. Ten percent (10%) for
the first ten (10) feet away from the structures is the sug-
gested slope.
(3) Cackfill around the outside perimeter of the structures
should be mechanically compacted at optimum moisture to at
least ninety-five percent (95%) of Standard Proctor Density
AS'M D 698-78. (See Appendix C.) Puddling should not be
permitted as a method of compaction.
(4) Gutters and downspouts should be designed to carry roof runoff
water well beyond the backfill area.
(5) It is recormnded that all compaction requirements specified
herein be verified in the field with density tests performed
under the direction,of the geotechnical engineer.
(6) It is recormended that a registered professional engineer
Idesign the foundations using the recounendations presented in
this report.
GENERX COMMUITS
This report has been prepared to aid in the evaluation of the
property and to assist the architect and/or engineer in the design of
this project. In the event that any changes in the design of the
structures or their locations are planned, the conclusions and recommen-
dations contained in this report will not be considered valid unless
said changes are reviewed and conclusions of this report modified or
0
Residential Collector
Select Base Course 4" 7"
Asphaltic Concrete 2" 2"
Total Pavement Thickness 6" 9"
The base course overlying the subgrade should consist of a hard,
durable, crushed rock or stone and filler and should have a minimum "R"
value of 80. The composite base course material should be free from
vegetable natter and lumps or balls of clay and should meet the Colorado
Department of Highways Specification Class 6 Aggregate 3ase Course which
follows:
Sieve Size
% Passing
3/4"
100
y4
30-65
18
25-55
#200
3-12
Liquid Limit - 30 Maximum
Plasticity Index - 6 Maxinum
The base course should be placed on the subgrade at or near optimum
moisture and compacted to at least ninety-five pdreent (95%) of Standard
Proctor Density ASTfi D 698-78. (See Appendix C.) It is important that
the base course be shaped to grade so that proper drainage of the
pavement area is obtained.
The asphaltic concrete should meet City of Fort Collins speci-
fications or equivalent and be placed in accordance with those speci-
fIcations.
GENERAL RECOMMENDATIONS
(1) Laboratory tests indicate that water soluble sulfates in the
soil are negligibleg and a Type I cement may be used 1n all
concrete exposed to subsoils. All slabs on grade subjected to
4
G
resist swelling pressures which will develop if the subsoils become
wetted, footings should be designed for a minimum dead load pressure of
five hundred (500) pounds per square foot.
The anticipated settlement under the above -recommended maximum
pressures should not exceed three -fourths (3/4) inch.
Basements and Slabs on Grade
The subsurface profile encountered at the site will permit con-
struction of full basements if desired. The basenent finished floor
should be placed at least three ('I) feet above the groundwater levels
encountered in this investigation. j
Conventional slab -on -grade construction can be used. Preparation I
to slab -on -grade subgrade elevation should be accomplished as discussed i
In the "Site Grading and Utilities" section of this report.
All slabs on grade should be underlain by a minimum of four (4)
i
inches of gravel or crushed rock free of fines. The gravel layer will
act as a capillary break and will help to distribute floor loads. It is.
recommended that slabs on grade be designed and constructed independent
of all bearing members. To minimize and control shrinkage cracks which
will develop in slabs on grade, it is suggested that control joints be
placed every fifteen (15) to twenty (20) feet and that the total area
contained within these joints be no greater than four hundred (400)
square feet.
Pavements
Preparation to pavement subgrade elevation should be accomplished
as previously discussed in the "Site Grading and Utilities" section of
this report. Qualified geotechnical personnel should be present during
stripping of the topsoil, scarification of the subgrade, and placement
and compaction of fill in pavement areas.
AASHTO classifications of the on -site near -surface materials are A-
2-4 and A-6 with group indices 0 to.6. Based upon a group index of 6,
the following pavement thicknesses are recommended:
G
Backfill placed in utility trenches in open and planted areas
should be compacted in uniform lifts at optimum moisture to at least
ninety percent (90%) of Standard Proctor Density ASTM D 698-78 the full
depth of the trench. The upper four (4) feet of backfill placed in
utility trenches under roadways and paved areas should be compacted at
or near optimum moisture to at least ninety-five percent (95%) of Stand-
ard Proctor Density ASTM D 698-78, and the lower portion of these
trenches should be compacted to at least ninety percent (90%) of Stand-
ard Proctor Density ASTM D 698-78. Addition of moisture to and/or
drying of the subsoils may be required to assure proper compaction.
Proper placement of the bedrock as backfill may be difficult, as is
discussed above.
Qualified geotechnical personnel should be present during all
phases of earthwork to observe stripping of the topsoil, scarification
of the subgrade, and placement and compaction of fill. In -place density
tests should be taken daily to determine the degree of compaction being
attained and compliance with project specifications.
Foundations
Based upon the subsurface conditions encountered at the site and
the loads transmitted by the proposed construction, we recommend that
all structures be supported by conventional continuous or isolated
spread footings bearing in undisturbed natural sail or fill placed as
recommended above. As"on-site materials will be used for fill, struc-
tural fill placed and compacted as recommended above will have com-
parable shear strength and bearing qualities to those of the in situ
materials. Exterior footings should bear a minimum of thirty (30)
inches below exterior finished grades for frost protection. The nature
of the bearing soil should be verified by qualified geotechnical per-
sonnel prior to placement of foundation concrete.
Footings bearing at the above -recommended depths may be designed
for a maximum allowable soil pressure of one thousand five hundred
(1500) pounds per square foot under dead plus maximum live loads. To
H
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m
Site Grading and Utilities
We anticipate that some cutting and filling will be required on the
property to achieve desired finished grades. As building foundations
and/or slabs on grade may be supported on fill. we recommend that fill
placement be in accordance with FHA "Data Sheet 79G." The following are
our recommendations for site grading and placement of compacted fill.
The upper six (6) inches of all topsoil should be stripped in 1
proposed cut and fill areas and in building and pavement areas which ;
will remain at present grades. Slabs on grade and footings of the
buildings in the northeast corner of the site should be removed and
wasted off -site. The topsoil can be stockpiled on the site and used for
final grading outside of building and pavement areas. At cut subgrade
elevation and in areas to receive fill, the upper six (6) inches of the
subgrade should be scarified and recompacted at two percent (2N) wet of
optimum moisture content to a minimum of ninety percent (900N) of Standard
Proctor Density ASTM D 698-78 (See Appendix C.)
The on -site overburden materials are suitable for use as fill in
proposed building and pavement areas. Any additional off -site fill
required should be a material approved by the geotechnical engineer. We
recommend that all fill be placed in horizontal six (6) to eight (8)
inch lifts at two percent (2%) wet of optimum moisture content and
compacted to a minimum of ninety-five percent (95%) of Standard Proctor
Density AST14 D 698-78.
Where fill is placed on slopes greater than 4:1. horizontal benches
should be cut in the slopes to insure integrity of the new fill on the
existing slopes. For stability, vie recommend that all cut and fill
slopes be no steeper than 2:1; however, flatter slopes are suggested for
ease of maintenance. Finished slopes should be seeded with native
grasses to minimize erosion.
We anticipate that no unusual problems will be encountered during
excavation for installation of utilities. We anticipate that the over-
burden materials will be stable on temporary 1:1 cut slopes. Dewatering
may be required if utility excavations extend below the groundwater
table.
t
n
Piedmont, formed during Late Tertiary and Early Quaternary time (ap-
proximately sixty-five million (659000,000) years ago), is a broad,
erosional trench which separates the Southern Rocky Mountains from the
High Plains. Structurally, the site lies along the western flank of the
Denver Basin. During the Late Mesozoic and Early Cenozoic Periods
(approximately seventy million (70,000,000) years ago),/intense tectonic
activity occurred, causing the uplifting of the Front Range and the
associated downwarping of the Denver Basin to the east. Relatively flat
uplands and broad valleys characterize the present-day topography of the
Colorado Piedmont in this region. The site is underlain by the Cre-
taceous Pierre Formation. The Pierre shale is overlain by alluvial
soils of Pleistocene and Recent Age.
Bedrock outcrops were not noted at the site nor were they encoun-
tered in the test borings to depths fourteen and one-half (14-1/2) feet
below the surface. It is estimated that the bedrock underlies the area
at depths approximately thirty (30) feet below the surface. The regional
dip of the bedrock in this area is slight and in an easterly. direction.
From a structural standpoint, the property is relatively stable and
seismic activity is not anticipated. Due to the relatively flat nature
of the property, geologic hazards due to mass movement caused by gravity
such as landslides, mudflows, etc., are not anticipated. With proper
site grading around all structures and proper drainage for all roadways,
erosional problems should be r:inimal. It is recommended that the struc-
tures not be placed within fifty (50) feet of the Pleasant Valley and
Lake Canal. The property lies within the drainage basin of the Cache La
Poudre River; however, it does not lie within the flood plain of this
stream or any other stream. Therefore, it is not subject to major
stream flooding.
Geologic conditions necessary for the formation of economic minerals
such as coal. limestone, quarry rock, and sand and gravel are not present,
in our opinion. to economic depths at the site.
I
n
f
a
through the existing pavement on Norsetooth Road. Thickness
of the asphalt in this boring was three (3) inches. The
asphalt is underlain by approximately two (2) feet of sand and
gravel subbase material.
(2) Sandy Silty Clay: The topsoil and fill are underlain by brown
and red sandy silty clay with some fine gravel extending to i
the depths explored. This soil is heterogeneous, the per-
centages of sandq silt, clay, and fine gravel varying with
location and depth. Distinct layers and zones of silty fine
sand and some fine gravel were encountered within this stratum. }
In its natural, undisturbed conditions the sandy silty clay,
has low to moderate shear strength and bearing characteristics.
Upon wetting, the more clayey portions of this stratum exhibit
minor swell potential.
(3) Groundwater: M water was encountered in Borings 1 through 10
and 14. Water was encountered in Borings ll, 12, and 13
approximately ten (10) to fourteen and one-half (14-1/2) feet
below present grades. Groundwater levels at the site will
fluctuate with seasonal variations and conditions and irri-
gation demands on and adjacent to the site.
ANALYSIS AND RECOMMENDATIONS
We understand the investigated property will be developed for patio
homes and townhouses. The following are our recommendations for develop-
ment of the site as influenced by the subsurface conditions encountered
in the test borings.
Geology
The proposed development is located within the Colorado Piedmont
section of the Great Plains physiographic province. The Colorado
0
a
SITE LOCATION AND DESCRIPTION
The project site is located on the south side of Horsetooth Road
west of Shields Street, southwest of Fort Collins. Colorado. More
specifically. the site is situate in the northeast 1/4 of Section 34.
Township 7 North, Range 69 Nest of the Sixth Prime Meridian, Larimer
County, Colorado.
The property is presently an open, grass- and weed -covered field.
f
A barn and outbuildings are located in the northeast corner of the site.
The property slopes gently to the east with maximum relief on the site
approximately ten (10) feet. An irrigation ditch forms the east prop-
f
erty line of the site. Residences are located west of the property.
The area to the south is presently open.
LABORATORY TESTS AND EXAMINATION
Representative samples recovered in the test borings were selected
for tests in the laboratory to determine their physical characteristics
and engineering properties. Included in the test program were natural
moisture content, water soluble sulfates, Atterberg limits, dry density,
unconfined compressive strength, consolidation characteristics, swell
potential, and swell -consolidation characteristics. Laboratory test
results are summarized in Appendix B.
SOIL AND GROUND'aATER CONDITIONS
The following are the characteristics of the primary soil strata
encountered at the site.
(1) Topsoil and Fill: Thickness of topsoil across the site varies
from approximately six (6) to twelve (12) inches. The upper
six (6) inches of the topsoil have been penetrated by root
growth and organic matter and are not suitable for foundation
bearing or as backfill material. Boring 14 was drilled
I
r
u
REPORT
OF A
GEOTECHNICAL INVESTIGATION
SCOPE
This report presents the results of a geotechnical investigation
prepared for the proposal subdivision to be constructed on Horsetooth
i
Road, southwest of Fort Collins. Colorado. The investigation included �
test borings. laboratory testing, engineering evaluation, and prepa-
ration of this report.
The purposes of the investigation were to determine subsurface
conditions at the site and to provide recommendations for development of
the site as influenced by the subsurface conditions. The-Ceology
section of this report was prepared by an engineering geologist of
Empire Laboratories, Inc.
SITE INVESTIGATION
Fourteen (14) test borings were drilled at the site on August 3.
1980. Locations of the test borings are shown on the Geologic Map and
Test Boring Location Plan included in Appendix A.
The borings were advanced with continuous -flight augers to depths
three and one-half (3-1/2) to fourteen and one-half (14-1/2) feet below
present grades. Samples were recovered with two and one-half (2-1/2)
inch Shelby tubes and the standard penetration sample technique. During
drilling, a field engineer of Empire Laboratories. Inc. was present and
made a continuous visual inspection of soils encountered. Logs prepared
from the field notes are included in Appendix A of this report. Indi-
cated on the logs are the primary strata encountered, locations of
samples, and groundwater conditions.
Branch Offices
Place
Empire Laboratories, InC• izaz Colorado
0501
t Longmont, Colorado 80501
P.O. Box 1135
MATERIALS AND FOUNDATION ENGINEERS (3031 776.3921
214 No. Howes Fort Collins. Colorado 80522 3151 Nation Way
P.O. Box 429 (3031 484.0359 Cheyenne, Wyoming 82001
August 26, 1980 P.O. Box 10076
(307) 632-9224
Cornell Consulting Company
155 North College Avenue
Fort Collins, Colorado 80521
Attention: fir. Greg Hurst
Gentlemen:
We are pleased to submit our Report of a Geotechnical Investigation i
prepared for the proposed subdivision on Horsetooth Road, Fort Collins,
Colorado.
The subsurface conditions revealed by this investigation are suitable
i for the intended construction, provided construction is in accordance
with the recommendations contained in this report. The attached report
presents the subsurface conditions at the site and Our recommendations
for development of the site.
We appreciate this opportunity of consulting with you on this project.
If you have any questions or if we can be of further assistance, please
contact us.
Very truly yours, `��� �4S E•VF�:;;,
��• 'aIs=�q�•:ti~-
EMPIRE LABORATORIES, INC. _� 4
SE to 15919
0,0
i James E. Ve i th , P.E. y�.•`oor,��
Geotechnical Engineer V;-'<`OF.••��pP r
Iyiipirrrrn nonr.z \
Reviewed by: `�=1� gal:' vA��!
!i • i
Chester C. Smith, P.E. -
4-808
President
1, 61;0 a �.�' ••
Clc O; CO��
v'SORAr
'M' I MEMBER OF CONSULTING ENGINEERS COUNCIL
4 2/ 1
TABLE OF CONTENTS
Table of Contents ..............................................
Letter of Transmittal ..........................................
Report.........................................................
Appendix A .....................................................
Geologic Map and Test Boring Location Plan ...................
Key to Borings ...............................................
Log of Borings ...............................................
Appendix B.....................................................
Consolidation Test Data ......................................
Summary of Test Results ......................................
Appendix C.....................................................
Appendix D.....................................................
Soil Map ......................................................
Soil Description .............................................
A-3
i
A- 4
C-1
D-1
D- 2
D- 3
C
F
-4
REPORT
OF A
GEOTECHNICAL INVESTIGATION
FOR
CORNELL CONSULTING COMPANY
FORT COLLINS. COLORADO
i PROJECT 140. 4142-80
RE: PROPOSED SUBDIVISION
FORT COLLINS, COLORADO
i
E
i
i
BY
EMPIRE LABORATORIES. INC.
214 NORTH HONES STREET
FORT COLLINS* COLORADO
80521
A ,U'di 7 �I Z�'it trhEo
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