HomeMy WebLinkAboutSubsoil StudyCLVCO Engineering, fnc.
Civil Engineerirg Consulfonts
P.O. Box 1758
3ó5 West 50 North, Suite W-l
Vernol, Ufoh 84078
June 14,2021
Shavn Ruse
Glaybn Hornes
671 23 Road
Grand Junction, CO 81505
Vøifr that the project site is not al the mouür of any obvious dnainage,
in his letterfor loarering he dsk of frost hEave are also key to Þssening
RECËIVEÐ
.-,îfffii,i#.ÊP##,1ïDear Shawn,
Subl.cù Soll lnvestlgatbn- 55i18 GR 3O9, Panaoh¡te, Colorado
I am writing his letþr b report the findings of a soil investþtion ftat was ænducted at the popæed
site br the residence at 5538 County Road 309, near Parachute, Colorado. The invesligation entailed
he analysis of one soll sample that was taken from the proposed construdion site at approxirnately the
bearing depth of the proposed foundation" Testing of he soil sample hduded a sieve analysÍs and
A[arberg Limib testing. The test results were used to classiff he scilsample as'CL-ML' according to
he Unified SoilClasslfication System. Copíes of the soil data are included wtür this letter.
CL-ML soils are inorgnnic days of low to medium plasticity wiitr silt. Literature suggests that medium to
stiff CL-ML soils are likely to have bearing capacitiæ in the range of 3,ü)0 psf. Recogniz¡ng that no
specific bearing capacity testing was perbnned, I æoorttrnnd hat a more conseruative bearing
capacity of 2@0 psf be used br design purposæ.
Over the yeɡrs, a number of studies have been condtrled in an efbrt to conelate soil expansiveness
b atterberg limit data. According b one study, soils wih Liquid Umlls less than 50olo and Plastkity
Indices that less han 25olo, generally have a lor potential for expansion (Snethen, Johnson, and
Pafick. 1977t. The soil sample tested was bund to have a Lþuid Umit of 25% and a Plasticity lndex of
5o/o, Thus, according to the referenced study, he sclil in question is anticipated to have a lor
expansion potential. lt shoukf be noted hat Atterberg Limlts testing does not address mineralogy and
hus may have a limited ability to rellably predict sclilexpansion potentlal,
CL-ML soils oñen are susceptible to frost heare. tìIethds should be implernented trc lessen the
likelihood of fttost heave. Foundaüons shor¡ld extend b belor ftost depttr or be frost-proteded by some
other means. l/Ibter should be kept away from üre bundation. \lValkways, driveways, and grourrd
surfaoes shouH be gnaded to fror away from he bundation. Gutter dorn-spout outlets should be kept
at least five Þet away fiom üe fuundation. Vegetration requiring signiñcant watering should not be
planted near the fcundation.
No testing was done to determine the sril's collapse potential. ln my experience, bundation failures
due to soilcollapee are generally even more cahstrophic than hilures due to soilexpansion. ln every
instance of soil collapse åilure that I have investþated, the damaged hone was locatEd at the mouü,r
of a pronounced drainage, such as a canyon ø gully where the scil has been depo$ted allwially by
intenníttent ru noff water fl ors,
Alluviallydeposited soib are typically not very dense and dedve their sfength from minenal bonds that
furm between soil particles, Wæn these soils becoma wet, the mineral bonds dissolve, alowing tfre
xil pailicles to consotidate (ccllapse) under arry load that is in excess of that whiü existed when the
mineral bonds orþinally bÍned.
The methods næntioned earlier
the risk of soil collapse failure.
Phoæ (435P89-5448' For (435Y89-.1465
Email ¡ vqnc€k¡ng@cÍvcoengineering. com
. Page 2 June14,2o21
ln sumrnary, the xil under lhe bundation was rrot speciñcally tesed tc determine ib otpanaiveness
but rcsulb of ateÈerg limits testing suggest ürat he soil has a lour e¡eansion potential. Likqlise, the
soilwes not speciñcalfi teSed b dete¡mine bearing oapacrty but was found to be of a Uæ lnvfng
charderistiê bearing capacities in the range of 3000 psf. For deslgn purpoces, a 2000 æf bearing
capedty b rccomrnended. No specific bsling was perbrned þ determine the colhpse poÞntial of ttre
so¡|. The honreowner should make every eftltto keep moisture from being inboduced to he sol near
he bundation, Any fubre purdtaser of he horne should be apprise<f of tre underlying soil
úamdedstics and he imporlance of keephg moistr.¡¡e auny from he bundafon.
This condudes my teport Please note ürat this inveotigalion was perfomed br üre purpose of
provitling gemnal inbnnation rcgarding the soll underlying he goposed home and makes no
predi<fþn of lbundation perfurnance. This pport should not be ægarded as documenEtion of a
geotechnical investþation æ I am not a geobdrnical engineer, and üris study utas not conduded to
any generally accepted st¡andard of geoÞdrnical engineøing prac-lice, Pþase conÞct nr if yor have
queetions rcgading hb rcport.
Sincerely,
VanceV. King, PE
Engineer
CIVCO Engineering, lnc.
Errcloeure
Cc: Project File
o þ
53531
Q. C. Testing. lnc
2944 S 1500 E
VERNAL, UTAH 84078
Phone (435) 789-0220
Fax (435) 781-1876
stEVE ANALysts AND ATTEBER. LtMtrs
- 5538 CR 309,co
0. c- r[srlHß
-
Prd€ct No. or Client:
Matoial Type:
Distånce fom CL:
MF=
natiræ - unifred sdl clæs¡ficalim
ctvco
Statime:
D€pth:Date Sampled Dale Tested;ø110t2021
UNIFIED Attøbøg limll
lzsUsld Urit
lzoPbrl¡c L¡íll
FT83t¡c húr ls
gbs¡iliilton IcL-Ml--siltv ctav wlth ssnd
*4 Mdeture Þata
W€[wl.405.6
Drv Wt.371.5
H20 Wr.34,r
H2Oo/o 9.2
Washed Drv Wt.72.4
Teated By TD
AASHTO T-27 Coarse Grdatlon
Slwe
Slzo
Welght
Ret.7o Rel.
7o Total
Pæslns
Siwe
Slze
3'tz¡m)3n
2" t¡om)
1.5" laz.snm¡1.5"
1n l2¡nm)1
3¡|4" (lûlm)3/4"
1/2" (iz.6rrn)1t2'
3/E" to,¡rrnl 3/8',
þ4 g7&ûr'1 u
#4 t¿.zgrr¡)
WETWT.
+4 (475mm)
DRY WT.
Total
Fins Gradation
Slzo
Weight
R€t.7o Rel.% Pass
fi4 {¡.zsm)
f8 ta.sorm)0 0.0 100
#1 0 ¡a,onrn¡3.r 0.8 99.2
#10 tr.lsr¡ml
il20 taso¡rnl 4.5 1.2 s8.0
f30 toær¡nl
il40 t¡zsrnl 6.9 1.9 s6.t
f1.50 rsæml
f60 teso¡¡¡l
fBO ttæpnl
#100 rcolml
#200 53.7 14.5 81.6
#200 ü5um)303.3 8r.6
Total
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