HomeMy WebLinkAboutSANCTUARY WEST - PDP - 30-07 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTGENERAL NOTES
DFMMNG & SAMPLING SYMBOLS:
SS: Split Spoon -1?fir I.D., 2. O.D., unless Ctier im noted HS: Hollow Stem Auger
ST. Thh-Walled Tube - 2' O.D., unless otferwise noted PA Power Auger
RS: Ring Sannplsr - 2ALr LD., 3° O.D., unless oifmmfte noted HA: Hand Auger
DB: Diamond Bit Coring - 4', N, B RB: Rock Bit
BS: && Saute cr Auger Sample WS: Wash Boring or MA Rotary
The number of blows required to advance a standard 24u;h O.D. 80kq)wn senior (SS) to last 12 inches of the total 184wh
penetration vAlh a 140-pound hammer falling 30 inctres Is considered the 'Standard Penetration' or N-YaW. For 3' O.D. ring
samplers (RS) the penetration value Is reported as five number of blows required to advance foe sampler 12 inches using a 140-
pound harnmer 69M 30 inches, reported as meows per toot," and is not considered equivalent to the'Standard Penetration! or 94-
poW
WATER LEVEL MEASUREMENT SYMBOLS:
WL: Water Level WS- WhQe Sarnpllng
WCI: Wet Cave in WD: Wtnfle Drilling
DCL Dry Cave In BCFL• Bore Casing Rernovsi
AB: After Boring ACR: Ater Casing femoral
Water levels indicated on the boring logs are foe levels measured in the borings at the tines indicated. Groundwater levels at other
tines and other locations across the site could vary. in pervious soils, the indicated levels runny reflect tie legion of groundwater.
in low permeability soils, the accurate detrenliudlon-of groundwater levels may not be possible with only dmrMerm observations.
DESCRIPTOE SOIL CLASSIFICATION: Soil won is based on the Unified ClassBrstion System. Coarse Grained Sofls
have more than 50% of #mk dry wel*M retained on a #2M sieve; ihetr principal descriptors are: bouldem cam, gravel or sand
Fine Grained Sous have less than 500A of thetr dry weight retained on a 9110 sieve: UM are principally dam as days if they are
plastic, and sills if flay are sfightiy plastic or nor►pfastim Major constituents may be added as modifiers and .ninon oonsil tuents may
be added according tD the relative proportions based an grain size. In addition to gradation, c oarse'gafred soft are defined on the
fasts of their la-plars relative density and fsa sails on five basis of 8n3ir consistency.
F NEGRAINED SOILS COARSE43RAINED SOILS BEDROCK
Sk-M-Aft Blowaft Conslstarw Blows Blowsifft Dentafty Bl� Blowalft Consistency
<3 <2 Very Soft 0.6 <3 Very' <30 <20 Wed
3.4 23 Soft 7-18 48 Loose 30-49 200 Firm
5.9 4-6 Medlum Stiff 1958 10 29 Mullum Dose 50-89 3D49 Medium llaM
10-18 7-12 Stiff 59-98 30-49 Dense 90-119 50-79 Hard
19-42 13 26 Very Stuff > 98 > 49 Very Dense > 119, > 79 Very Hard
> 42 > 26 Hard
RELATIVE PROPORTIONS OF SAND AND GRAIN SIZE TE MOLOGY
Descriotive Terms of Pew Malor Comoanernt
Other Constiba ft Dry WeloM M Samole Particle she
Trace < 15 Boulders Over 12 in. (300mm)
With 15 — 29 Cobbles 12 l n. to 3 in (300mrn to 75 mm)
Modifier > 30 Gravel 3 In. to?4 stave (75mm to 4.75 mm)
Send #4 to #X100 stave (4.75mm to 0.075mm)
Silt or Clay Passing #2110 Sieve (0.075mm)
RELATNE PROPORTIONS OF FINES PLAS71CfiY DESCRIPTION
Descrfotive Terns of percent
Other Consfte nts Dry WeloM Term PlasticityIntJenc
Trace <5 Non -plastic 0
With 5=12 1 Low 140
Modiflsrs > 12 Medium 11-M
High 30+
1rerracon-
UNIFIED SOIL CLASSIFICATION SYSTEM
Cdforla larAsslwdng Group Symbols °ref Grump Haase gulag L&.,.toryTarrte"
Coarse Grahred Sells
More Oran 50% relai eel
an No. 200 slave
Cu24aad1sCcs3°
Cu <4 andfbr 1 > Cc> 3F
Fires classify as ML or MH
Fires classify as CL or CH
Cu2:6and15Cas3'
Cu <6 andAor 1 > Cc> 9r
Flnes mmwyasMLorMH
Flra d siyasG2 orCH
Fim-Grffired Soils Sfts and Clays Inormu fa P1 > 7 mid plots an or Wx Aire'
No 200 slave Peres Ore Liq BY& lass omit 50
PI<4ornw-bel A One'
Liquid 16nit - oven
dried <0.75
ugtdd um)t-not
Gravels
Gear Gravels
More than 50%, of mass
Loa Pharr 5%*,Be
fi don retained on
No. 4mere
Gravais"mRrres More
than 12% fine
Sands
Clean Sands
50%or mom ofcoarss
fiadion
LOW #=5%flaee
passes
No. 4slave
Sands wMtFlnes
Mae than 12%lire&
Inmoanic
� �a w awns
organic
PI flots on crabova A Bne
PI plots hemmer A &re
LigWd �@-ward dried
►mod Omit- rid died
dark In color, arei alum odor
Based an Ore materiel passing an 34
n. g5_n n) slave
s If field aamPle cordaired cobbles or boulders, or bdh. sold NmMr cobs
or bouldem or boor' to group nrenrs.
cGravelo wflb 5 to 12% fines regtdre dual symholw GW-GM wag graded
gmvd wMn sk GWLGC wen waded gravel wah day, Gp.GM pony
graded !paver With edit. GP -GC Paaly graded gmvd with day.
'Sands With 5 to 12% Mm mquha dual eyrbcm SWSM wag graded
Band w0h sM, SW -SC wan graded sand with day, SpSM poorly graded
sand wind sM, SPSC POay leaded seed with day
eCu=pollDm Cc=(D3oL
Dm X Dw
r ff Sogcadabre 215% send, add er r Send' to group name.
elf fees classify as CL-AL. we duals QC-W or W. SK
dr
10
7
4
0
<0.75
GW Well Waded gparrer
GP Powly graded g neeV
GM SfOy aavePA"
SW Wall Waded sand
SP Poorly waded satrd
SM SOLYSMWv
SC Claysyr +s
CL Leaner
ML
OL Organic day"
CH Fatdayum
MH Efasft dLVAX
OH Orgardcd
OrgenlodrA°
PT peat
"If fires are agim add itdnr orgaade fines' to gaup name.
r Bsail cul-W 215%gravel. Odd Wdh graver to group Oars,
r IfPdb3d)M ftft Plot In shaded area, 8W Is a CL-ML, silly day.
KIf 800 m loins 15 to 29% plus Ho. 200. add '1 M sands' or WM
WBYW whichever Is p edorhrenL
L if SW contefns 2 30% phis No.
200 Pnedo wind, add .saw to 9om rmme.
"If 8oB mrbihre 2 30% pits No. 2O% predomhm* gravel. add
1wavew to group More.
"PI 24 and plots an or above i4' Bits.
ePl <4 r plots bebW A Bite.
°PI plolo an or above A one.
ePl.plotabeimv: A: Bos.
Pm
�sUaWdan
�dreOsnaf7r-ire
Af�'
fbammml at Pbeto' 1=258.
�P�
Omm a7slLL4" .
•�
.
O•j•
6qumionofIV-am
VWfics! at U,18 to
�c8
Oren Pk" (LL 8)
% d1r
d,
MH or
OH
'lot
,'
MLrOL
0 W 16 m 30 40 m W 70 W .00 1O0 /10
LIQUID UW (LU
ROCK CLASSIFICATION
(Based on ASTM C M)
Sedimentary Rocks
Sedimentary rocks are stratified materials laid down by water or wind. The sediments may be
composed of Particles or preexisting rocks derived by mechanical weathering, evaporation or b
chemical or organic origin. The sediments are usually indurated y
by cementation or compaction.
Chart Very tine -grained siliceous rock composed of m
quartz, chalcedony or opal. Chert is various colored,lli s or ease, ryhard
and
has a conchoidal to splintery fracture, bus b dense, bard and
Claystone Fine-grained rock composed of or derived by erosion of silts and clays or any rock
containing day. Soft massive and may contairi carbonate minerals.
Conglomerate Rods consisting of a considerable amount of rounded gravel, sand and cobbles
with or without interstitial or cementing material. The cementing or interstitial
materials.
material may quartz, opal, calcite, dolomite, day, Iron oxides or other
Dolomite A fine-grained carbonate rock consisting of the mineral dolomite (CaMg(Co ,)2j.
May contain non -carbonate Impurities such as quartz, chart, day minerals,
organic matter, gypsum and sutitdes. Reads with hydrochloric add (HCL).
Limestone A fine-grained carbonate rock consisting of the mineral calcite (CaC%). May
contain non -carbonate impurities such as quartz, chart, day minerals, organic
matter, gypsum and sulfides. Reacts with hydrochloric add (HCL).
Sandstone Rods consisting of particles of sand with or without interstitial and cementing
materials. The cementing or Interstitial material may be quartz, opal, calcite,
dolomite, day, iron oxides or other material.
Shale FIne-grained rock composed of or derived by erosion of silts and d
containing day. Shale is hard, platy, of fissile may be days or any rock
Wean acid d - — - _ y-.--9rayhale . reddish or
rr[ey cot�iii�some carbonate minerals (p-11'caneous sha e
Sittstone Fine grained rock composed of or derived by erosion of silts or rock containing
silt Siltstones consist predominantly of sift sized particles (0.0625 to 0.002 mm In
diameter) and are intermediate rocks . between daystones and sandstones and
may contain carbonate minerals.
I
LABORATORYTEST
SIGNIFICANCE AND PURPOSE
TEST
SIGNIFICANCE
PURPOSE
California Bearing
Used in -ovahrate the potential strength of subgrade soil,
Pavement Thickness
Ratio
subbase, and base course material, including recycled
materials for use In road and airfield pavements.
Design
Consolidation
Used to develop an estimate of both the rate and amount of
Foundation Design
both differential and total settlement of a structure.
Bearing Capacity,
Direct Shear
Used to determine the consolidated drained shear strength
of soil or rock.
Foundation Design,
Dry. Density
Used to determine the in -place density of natural in organic,
MomStabil
Index Property Sofi
fine-grained soils.
Behavior
Expansion
Used to measure the expansive potential of fine-grained
soil and to provide a basis for swell potential classification.
Foundation and Slab
Design
Gradation
Used for the quantitative determination of the distribution of
Soil Classflication
particle sizes in soil.
Liquid & Plastic Umif,
Plasticity Index
Used as an integral part of engineering classification
systems to characterize the fine-grained fraction of soils,
Sol/ C/ass/flcaiton
and to specify the fine-grained fraction of construction
materials.
Permeability '
Used to determine the capacity of soil or rock to conduct a
GmundwaterFlow
liquid or gas.
Analysis
PH
Used to determine the degree of aridity or alkalinity of a
Comps/on P_otenNa/
soil.
Resistivity
Used to indicate the relative abiiity of a soil medium to Carry
Comps/on Potential
electrical c uffents.
R-Value
Used to evaluate the potential strength of subgrade soil,
subbase, base
Pavement Th/ciwess
and course material. Including recycled
materials for use in road and airfield pavements.
Design
Soluble Sulfate
Used to determine the quantitative amount of soluble
sulfates within a soil mass.
Corrosion Potengal
Unconfined
Compression
To obtain the approA mats compressive strength of soils
that possess
t possess sufiident cohesion to permit in the
Bearing Capacity
ned state. g
uncWater
Analysis for
Content
Used to determine the quantitative amount of water in a soil
ys
index Foundations
property So/l
mass.
Behavior
reuracm-----j
REPORT TERMINOLOGY
(Based on ASTM D653)
Expansive The potential of a soil to expand (increase in volume) due to absorption of moisture.
potential
Finished Grade
The final grade created as a part of the project
Footing
A portion of the foundation. of a structure that transmits loads directly to the soil.
Foundation
The lower part of a structure that transmits the toads to the soil or bedrock.
Frost Depth
The depth at which the ground becomes frozen during the winter sewn.
Grade Beam
A foundation element or wail, typically constructed of reinforced concrete, used to span
between other foundation elements such as drilled piers.
Groundwater
Subsurface water found in the zone of saturation of soils or within fractures in bedrock
Heave
Upward movement
Lithologic
; The characteristics which describe the composition and texture of soil and rock by
observation.
Native Grade
The naturally occurring ground surface.
Native Soil
Naturally occurring on -site soil, sometimes referred tb as natural soil.
Optimum Moisture
The water content at which a soil can be compacted to a maximum dry unit weight by a
Content
given compac Live effort
perched Water
Groundwater, usually of limited area maintained above a normal water elevation by the
presence of an intervening relatively impervious continuous stratum.
Scarify
To mechanically loosen soil or break down existing soil structure.
Settlement
Downward movement
ShMFrictlon.(S/de
ftmali�l.tin-soiljand.anslemant,of the-structure.such_asa
Shear)
drilled pier.
Soy (Earth)
Sediments or other unconsolidated accumulations of solid particles produced by the
physical and chemical disintegration of rocks, and which may or may not contain organic
matter.
Strain The change in length per unit of length in a given direction.
Stress The force per unit area acting within a soil mass.
Strip To remove from present location.
Subbase A layer of specified material In a pavement system between the subgrade and base course.
Subgrade The soil prepared and compacted to support a structure, slab or pavement system.
No Text
5
P
L
A
S 41
T
1
C
T 31
Y
I
D 21
E
X
11
CL
CH
00,
1
i:0000K
I
O
O
CL AAL.
I
0 20
40
60
80
1on
Specimen Identification LL PL PI %Fines Classification
Vl 15.Oft 24 14 10 49 CLAYEY SAND(SC)
9-Oft 36 17 19 47 CLAYEY SAND(SC)
ATTERBERG LIMITS RESULTS
1 reffamn Project Proposed Detention Ponds
Site: N. of Laporte Ave and W. of Taft Hill Rd_ Fort Collins, Colorado
Job#: 20075075
No Text
LOG OF BORING NO. 6
CLIENT ARCHITECT / ENGINEER
Solitaire Homes, LLC.
SITE N. of Laporte Ave and W. of Taft Hill Rd. PROJECT
Fort Collins, Colorado Propose
SAMPLES
DESCRIPTION
TOPSOIL
SANDY LEAN CLAY
Medium stiff, reddish brown
BOTTOM OF BORING
J
C
O
m
�
x
w
w
U)
m
w
°
w
U)
Z)
o
z
o:
d Detention Ponds
TESTS
o
w
W n
z
F
Z ~
Z 0
2
-
5
10
CLI
SS
ISSI
12
6
1 27
CL
SS
SS
12
6
24
CL
SSr
12
9
015
1 of 1 I
The stratification lines represent the approximate boundary lines
between soil and rock types: in -situ, the transition may be gradual.
WATER LEVEL OBSERVATIONS, ft BORING STARTED 9-21-07
WL1-07
5 WD Filled In AB Irerracon R GRING COMPLETED CM.
55FOREMAN 9 CMG
WL Water Level Reading on 9/25/07 APPROVED RDL JOB # 20075075
LOG OF BORING NO. 5
Page 1 of 1
CLIENT
ARCHITECT / ENGINEER
Solitaire Homes, LLC.
SITE N. of Laporte Ave and W. of Taft Hill Rd.
PROJECT
Fort Collins, Colorado
Proposed Detention Ponds
SAMPLES
TESTS
o
DESCRIPTION
O
Da
z i
U
2
y
W
W
Z
Z
LL�
O
~ of Z
}
ow
C
a
U
a
O
0n
i
W
m
�0
o n
5co
0.5 TOPSOIL
SANDY LEAN CLAY
very soft, reddish brownCLRSSS
12
0'
24
112
6 Clay lenses observedCLAYEY
SAND
loose, brown tan
SC
SS
SS
12
4
23
15
CLAYSTONE
Weathered, tan, olive rust
15
SS
SS
12
15
21
BOTTOM OF BORING
The stratification lines represent the approximate boundary lines
between soil and rock types: -in-situ, the transition may be gradual. 'sample was advanced underweight of hammer
WATER LEVEL OBSERVATIONS, ft
Irerracon
BORING STARTED 9-14-07
2 WD
2 AB
BOMPLETED9 4-07
COME
WL
-7
m
R GRING
551
FOREMAN CMG
WL
Water Level Reading on 9/25/07
APPROVED RDL
I JOB # 20075075
LOG OF BORING NO. 4
CLIENT ARCHITECT / ENGINEER
Solitaire Homes, LLC.
SITE N. of Laporte Ave and W. of Taft Hill Rd. PROJECT
Fort Collins, Colorado Pr000st
1
DESCRIPTION
CLAYEY SAND
medium dense, brown, tan, calcareous
very dense, reddish brown
BOTTOM OF BORING
SAMPLES
J
C
m
r
w
W
_
j
o
w
o
co
z
W
t
'
10
15
CL
2
SS
1
CL
3
SS
1
Detention Ponds
o
N
uQ O
z
z(D
Z
Z
zz
Z
O
ou
�0
U
O n
1 of 1
The stratification lines represent the approximate boundary lines
5
between soil and rock types: in -situ, the transition may be gradual.
WATER LEVEL OBSERVATIONS, ft BORING STARTED 9-14-07
jWL 5.5 WD 5.5 AB Irerracon
4-07
RIG RING COMPLETED
9 CMG
o WL Water Level Reading on 9/25/07 APPROVED RDL I JOB # 20075075
LOG OF BORING NO. 3
Page 1 of 1
CLIENT
ARCHITECT / ENGINEER
Solitaire Homes, LLC.
SITE N. of Laporte Ave and W. of Taft Hill Rd.
PROJECT
Fort Collins, Colorado
Proposed Detention Ponds
SAMPLES
TESTS
DESCRIPTION
m
"' i
U
K
w
z
LL~
_
_
co
w
Co
>
rn
(rw
F z
Z
2
}
Zz
Ov
moo_
a
U
a
o
p
M
U
z
of
m
�0
on
�en
0.5 TOPSOIL
SANDY LEAN CLAY
stiff to very stiff, brown, tan, calcareous
' Silty sand with gravel lens encountered
1
CL
1
IRS1
12
25
25
5
CL
2
SS
12
16
15
10
15
15
CL
3 ISS
12
13
24
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, ft
Irerracon
BORING STARTED 9-14-07
WL
SZ 4.5 WD
IT4.5 AB
COMPLETED 9-1
WL
3
�
RIG CME 55
C4-07
FOREMAN MG
WL
Water Level Reading on 9/25/07
APPROVED RDL
JOB # 20075075
LOG OF BORING NO. 2
CLIENT ARCHITECT / EN
Solitaire Homes, LLC.
SITE N. of Laporte Ave and W. of Taft Hill Rd. PROJECT
Fort Collins. Colorado
0
O
U
a
DESCRIPTION
SANDY LEAN CLAY
Stiff to very stiff, brown, tan, calcareous
BOTTOM OF BORING
J
C
O
Co
�
c
W
=
ra
j
m
w
ai
n
w
}a}
O
D
Z
I-
0.'
to
d Detention Ponds
TESTS
o
w
W f
x
zF
W H
0 W
0
f-2
}
00
m
�00
O n
5h
1 of 11
The stratification lines represent the approximate boundary lines
between soil and rock types: in -situ, the transition may be gradual.
WATER LEVEL OBSERVATIONS, ft BORING STARTED 9-14-07
WL Q 2 WD 1 1.5 ABIrerracon RIG
GRING COMPLETED CME 55FOREMAN 9 CMG
WL Y4-07
Y
i WL I Water Level Reading on 9/25/07 APPROVED RDL I JOB # 20075075
LOG OF BORING NO. 1
Page 1 of 1
CLIENT
ARCHITECT / ENGINEER
Solitaire Homes, LLC.
SITE N. of Laporte Ave and W. of Taft Hill Rd.
PROJECT
Fort Collins, Colorado
Proposed Detention Ponds
SAMPLES
TESTS
of
DESCRIPTION
m
>
W f
U
}
co
of
w
Z
H
U_
Q
m
LU
0
WH
D
ow
o
Z)
z
of
m
36
o K
5to
0.5 TOPSOIL
SANDY LEAN CLAY
Brown, reddish brown
5-
to-
12
Approximate bottom of existing drainage
easement
CLAYEY SAND
Medium dense, brown, tan
SM
RSISSI
12
44
10
129
15
1
CL
SS
SS
12
9
29
20
Q
22
25
30
CLAYSTONE
Firm to hard, tan, olive rust
30
SS
SS
12
26
23
SS
SS
12
50
21
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, ft
BORING STARTED 9-14-07
WIL
21 WD
= 17 AB
9 4-07
ING COME
BORMPLETEDIrerracon
WL
IWL
�
�
RIG 551
FOREMAN CMG
Water Level Reading on 9/25/07
APPROVED RDL
JOB # 20075075
No Text
Ic�¢Rr erivsar
®-
I
LEGEND
- APPROXIMATE LOCATION OF TEST BORINGS, NO.1 - NOR
DN,ORAM S FOR OMVK LOCATION ONLY
AND 15 NOT INTENDED FOR CONSTRUCTION PURPOSES.
NEW
PONDS
PONDS
4
rlUURc l: all r- MAN
AND PIEZOMETER LOCATION DIAGRAM
NORTH OF LAPORTE AVE. AND WEST OF TAFT HILL ROAD
FORT COLLINS, COLORADO
200
lrerracon
GMo�md
Cma
M N. "mm S6ae1
AWWwder.
RLD
FOr1 Odit C*tado 0001
Dn mer.
FibNmm
2007S0T8.1 Ran Na
1
Preliminary Geotechnical Engineering Report
Proposed Sanctuary West Development
Three Proposed Detention Ponds
Fort Collins, Colorado
Project No. 20075075
Page 3
lrerrawn
Test Boring No. and Depth to Groundwater Below Ground Surface (ft)
Test Boring No.
1
2
3
4
5
6
Depth to Groundwater
Below Ground Surface
17`
1.5
4.5
5.5
2
5
(ft)
C) The bottom of the existing drainage easement was measured to be approximately 11 %z feet
below ground surface grade of the adjacent boring location. Therefore water level is anticipated
to be approximately 5 % below the bottom of the existing drainage easement.
Groundwater table updated from the table submitted in Terracon Report number 20075075
dated September 27, 2007 and should be used in leiu of the original dated September 27, 2007.
Based upon review of U.S. Geological Survey Maps, ('Hillier, et al, 1979), regional groundwater beneath the
project area is expected to be encountered in unconsolidated alluvial deposits on the site at depths ranging
from 10 to 20 feet below present ground surface.
If you have any questions or require further information, please feel free to contact us at your convenience.
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,
TERRACON CONSULTANTS, INC.
Christoph M. Gemperline
Engineering Geologist
Copies to: (5) Addressee
ymond L. Denton II,
Geotechnical Department
LO�'r0
402
;� v I to / 07 . •<(/�
'Hillier, Donald E.; and Schneider, Paul A., Jr., 1979, Depth to Water Table (1976-1977) In the Boulder -Fort Collins -Greeley
Area, Front Range Urban Corridor, Colorado, United States Geological Survey, Map 1-855-I.
V
Preliminary Geotechnical Engineering Report lferracon
Proposed Sanctuary West Development
Three Proposed Detention Ponds
Fort Collins, Colorado
Project No. 20075075
Page 2
Groundwater measurements were made in the borings at the time of site exploration and a minimum of one
day after drilling. Due to safety concerns, Test Boring No. 6 was backfilled after drilling therefore,
subsequent groundwater measurements could not be obtained.
The samples retrieved during the field exploration were returned to the laboratory for observation by the
project geotechnical engineer, and were classified in general accordance with the Unified Soil Classification
System described in Appendix C. Samples of bedrock were classified in accordance with the general notes
for Rock Classification. At that time, an applicable laboratory -testing program was formulated to determine
engineering properties of the subsurface materials. Following the completion of the laboratory testing, the
field descriptions were confirmed or modified as necessary, and Logs of Borings were prepared. These
logs are presented in Appendix A.
Laboratory test results are presented in Appendix B. Laboratory tests were performed in general
accordance with the applicable local or other accepted standards.
Selected soil and bedrock samples were tested for water content, dry density, plasticity index, and percent
passing a #200 sieve.
Site Conditions: The site was vacant and to our knowledge had not been previously developed and was
used for horse boarding purposes. The site was bounded on the west and north by an existing residential
development, on the east by an existing residential development with Taft Hill Road beyond, and on the
south by residential homes and a church with Laporte Avenue beyond. Vegetation consisted of a grass,
weeds, alfalfa, and sparse deciduous trees along Laporte Avenue. Other site features included existing
drainage easements on the north portions of the site.
Soil and Bedrock Conditions: As presented on the Logs of Borings, surface soils to depths of six inches
feet consisted of topsoil. The materials underlying the surface soils consisted of clay with varying amounts
of sand and sand with varying amounts of clay extending down to the full depth of exploration or to the
claystone bedrock below.
Field and Laboratory Test Results: Field test results indicate that the clay soils vary from soft to very stiff
in consistency. The sand soils vary from loose to medium dense in relative density. The claystone bedrock
varies from weathered to hard in hardness.
The following table shows the depth of groundwater measured from the ground surface elevations for the
test borings on September 25, 2007. Groundwater measurements for each boring are also shown on the
Log of Borings presented in Appendix A.
October 10, 2007
Solitaire Homes LLC Irerracon
6645 East Heritage Place South Consulting Engineers & Scientists
Centennial, Colorado 80111 301 North Howes
Fort Collins, Colorado 80521
Phone 970.484.0359
Fax 970.484.0454
Re: Groundwater Observation www.terracon.com
Three Proposed Detention Ponds at Sanctuary West
North of Laporte Avenue and West of Taft Hill Road
Fort Collins, Colorado
Terracon Project No. 20075075
This letter contains the results of our geotechnical engineering exploration. Based on information provided
by Solitaire Homes, LLC., the proposed project will include the development of a parcel of land north of
Laporte Avenue and west of Taft Hill Road in Fort Collins Colorado. The development will include the
construction of three detention ponds. Previously we prepared a geotechnical engineering report for the
proposed development dated December 15, 2007, (Terracon Project Number 20035190). The purpose of
these services is to provide subsurface soil and bedrock conditions and groundwater conditions to aid in the
design phases of the proposed detention ponds. Final site grading plans were not available prior to
preparation of this report. We understand the site is at or near construction grade and the ponds will be
designed by another engineering firm.
Field Exploration: A total of six (6) test borings were drilled on September 14, and 21, 2007 to depths of
about 15 to 30 feet below existing site grade at the approximate locations shown on the Boring Location
Diagram, Figure 1. The borings were drilled within or near the three proposed detention ponds within the
proposed Sanctuary West development as directed by Solitaire Homes, LLC. All borings were advanced
with a truck -mounted drilling rig, utilizing 4-inch diameter, continuous -flight auger.
The borings were located in the field by pacing from property lines and/or existing site features. Test
Borings Nos. 2 and 3 were placed at the bottom of an existing drainage easement. Test borings Nos. 4, 5
and 6 were placed within or near a proposed detention pond. Test Boring No. 1 was placed on the south
side of an existing drainage easement due to limited drill rig access. An elevation measurement with an
engineer's level was taken at Test Boring No. 1 and at the bottom of the existing drainage easement located
on the north side of the site in an effort to correlate the bottom of the existing drainage easement with the
offset boring location. The accuracy of boring locations and elevations should only be assumed to the level
implied by the methods used.
Lithologic logs of each boring were recorded by the engineering geologist during the drilling operations. At
selected intervals, samples of the subsurface materials were taken by driving split -spoon and ring barrel
samplers.
Penetration resistance measurements were obtained by driving the split -spoon and ring barrel into the
subsurface materials with a 140-pound hammer falling 30 inches. The penetration resistance value is a
useful index to the consistency, relative density or hardness of the materials encountered.
Delivering Success for Clients and Employees Since 1965
More Than 80 Offices Nationwide