HomeMy WebLinkAboutSoils Report 10.03.2019CIS CO Engineering, Inc.
Civil Engineering Consultants
P.O. Box 1758
365 West 50 North, Suite W-1
Vernal, Utah 84078
October 3, 2019
Shawn Ruse
Clayton Homes
671 23 Road
Grand Junction, CO 81505
Dear Shawn,
Subject: Soil Investigation — Haderlie Residence at TBD CR 237, Silt, CO
am writing this letter to report the findings of a soil investigation that was conducted at the proposed
site for the Long residence at TBD County Road 237, Silt, Colorado. The investigation entailed the
analysis of one soil sample that was taken from the proposed construction site at approximately the
bearing depth of the proposed foundation. Testing of the soil sample included a sieve analysis and
Atterberg Limits testing. The results of the soil testing were used to classify the soil sample as 'SC-SM
Silty, Clayey Sand' according to the Unified Soil Classification System. A copy of the soil data is
included with this letter.
SC soils are mixtures of sands, and fine soils. Bearing capacities for SC soils are typically 3000 psf for
loose soils. Recognizing that no specific testing was conducted to determine the soils actual bearing
capacity, I recommend that a smaller bearing capacity of 1500 psf be used for design of the home's
foundation.
Over the years, a number of studies have been conducted in an effort to correlate soil expansiveness
to atterberg limit data. According to one study, soils with Liquid Limits less than 50% and Plasticity
Indices that less than 25%, generally have a low potential for expansion (Snethen, Johnson, and
Patrick, 1977). The soil sample tested was found to have a Liquid Limit of 22% and a Plasticity Index of
5%. Thus, according to the referenced study, the soil in question is anticipated to have a low
expansion potential. It should be noted that Atterberg Limits testing does not address mineralogy and
thus may have a limited ability to reliably predict soil expansion potential.
Though the Atterberg Limits testing suggests a non -expansive soil, frost heave could still cause
problems for the foundation. Foundations should extend to below frost depth or be frost -protected by
some other means. Water should be kept away from the foundations. Walkways, driveways, and
ground surfaces should be graded to flow away from the foundation. Gutter down -spout outlets should
be kept at least five feet away from the foundation. Vegetation requiring significant watering should not
be planted near the foundation.
No testing was done to determine the soil's collapse potential. In my experience, foundation failures
due to soil collapse are generally even more catastrophic than failures due to soil expansion. In every
instance of soil collapse failure that I have investigated, the damaged home was located at the mouth
of a pronounced drainage, such as a canyon or gully where the soil has been deposited alluvially by
intermittent runoff water flows.
Alluvially-deposited soils are typically not very dense and derive their strength from mineral bonds that
form between soil particles. When these soils become wet, the mineral bonds dissolve, allowing the
soil particles to consolidate (i.e. collapse) under any Toad that is in excess of that which existed when
the mineral bonds originally formed.
Phone (435)789-5448 * Fax (435)789-4485
Email: vanceking@civcoengineering.com
a Page 2 October 3, 2019
Verify that the project site is not at the mouth of any obvious drainage. The aforementioned methods
for lowering the risk of frost heave are also key to lessening the risk of soil collapse failure.
In summary, the soil under the proposed foundation was not specifically tested to determine
expansiveness but was found to have properties consistent with soils having a low expansion potential.
Likewise the soil was not specifically tested to determine bearing capacity but was found to be of a type
having characteristic bearing capacities in the range of 3000 psf. For design purposes, a 1500 psf
bearing capacity is recommended. The home owner should make every effort to keep moisture from
being introduced to the soil near the foundation. Any future purchaser of the home should be apprised
of the underlying soil characteristics and the importance of keeping moisture away from the foundation.
This concludes my report. Please note that this investigation was performed for the purpose of
providing general information regarding the soil underlying the proposed home and makes no
prediction of foundational performance. This report should not be regarded as documentation of a
geotechnical investigation as I am not a geotechnical engineer and this study was not conducted to any
generally accepted standard of geotechnical engineering practice. Please contact me if you have
questions regarding this report.
Sincerely,
Vance V. KGng, PE
Engineer
CIVCO Engineering, Inc.
Enclosure
Cc: Project File
Q. C. Testing. Inc
2944 S 1500 E
VERNAL, UTAH 84078
Phone (435) 789-0220
Fax (435) 781-1876
Project No. or Client:
Material Type:
Distance from CL:
SIEVE ANALYSIS AND ATTEBERG LIMITS
CIVCO Engineering - Haderlie TBD CR237, Silt, CO
native - unified soil classification Stations:
Depth: Date Sampled
AASHTO T-27 Coarse Gradation
Sieve
Size
Weight
Ret.
% Ret.
% Total
Passing
Sieve
Size
Specs
3" (75mm)
3"
2" (5omm)
2"
1.5" (37.6mm)
1.5"
1"(26mm)
1"
314" (19mm)
314"
112" (12.5mm)
1 /2"
318" (9.5mm)
3/8"
#4 (4.75mm)
#4
-#4 (4.75mm)
WET WT.
44 (4.75mm)
DRY WT.
Total
MF=
Tested By CN
Fine Gradation
Size
Weight
Ret.
% Ret.
% Pass
#4 (4.75mm)
24.5
8.2
91.8
#8 (2.38mm)
#10 (2.0mm)
26.1
8.8
83
#16 (Ltemm)
#20 (mown)
#30 (600pm)
#40 (42509
35.1
11.8
71.2
#50 (300pm)
I
#60 (250pm)
#$0 (sWm)
#100 (15o1rn)
#200
97.4
32.7
38.5
-#200 (75(im)
114.9
38.6
Total
Remarks SOIL CLASSIFICATION (unified)
G_ TESTING
Date Tested: 9/2612019
UNIFIED Atterberg Limit
Wguidumit
22
Plank Limit
17
Phasic index
5
ctass6kalfon
SC-SMsilty, clayey sand
-#4 Moisture Data
Wet Wt.
316
Dry Wt.
298.0
H2O Wt.
18.0
H2O "%
6.0
Washed Dry Wt.
f
187.8
60
50
40
0
2
U30
E-
3
5
a- 20
WATER CONTENT
10
0
LIQUID AND PLASTIC LIMITS TEST REPORT
Dashed line indicates
upper limit boundary
for
the approximate
natural
soils
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ML gr
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MH gr
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%%%%fr�%/%%�
40
36
32
28
24
20
16
12
8
4
0
10
20 30 40 50
LIQUID LIMIT
80
•
5 6 7 8 9 10 20 25 30 40
NUMBER OF BLOWS
MATERIAL DESCRIPTION
native
LL
PL PI
22
17
5
% #40
%<#200
USCS
Project No. Client: Civco Engineering
Project: Soil Classifications
Location: Haderlie TBD CR 237, Silt, CO
QC TESTING, INC.
Tested By: TD
Remarks:
Figure
DATE: 101201E
DRAWN SY: VVK
SHEET S.1
FOUNDATION
HADERLIE RESIDENCE
T130 COUNTY ROAD 237
SILT GOLORADO
CLAYTON HOMES
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CIVCO Engineering, Inc.
P.O. Box 1758, Vernal, Utah 84078
Telephone: (435)789-5448 Fax: (435)789-4485
www.civcoengineering.com
REVISIONS
ReAsien Desailban
Rev. # Rev. Dale