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Home My WebLink AboutSoils Investigation 09.11.2018CIVCO Engineering, Inc. Civil Engincening Consultonts P.O. Box 1758 3ó5 West 50 North, Suile W-l Vernal, Utoh 8407E September 11,2018 Richald Ruse Chyton Homes 671 23 Road GrandJurction, GO 81505 Dear Richald, SüËJ.út Sdl hverügaüon-lúrorRerld¡nc¡ ll2l43 CR38, Predub, GD I am vulling to repolt the findings oi a soil inveatigation that was conducted at the proposed site for the Knox r*idence at 2145 County Road 36, Parachute, Colorado. The invesligation entailed lhe anaþis of onE soil sample that was taken at approximately the locatim and bearing depth of the ploposed foundation. Testing of the soil sample included a sieve anaþb and AtteÈerg Limits testing. The results of lhe soil lesting were used to classify the soil sampÞ as 'CL - Sandy Lean Cla/ according to the Unilied Soil Glassifhation System. A copy of tha solldata is included wiûr this letter. CL soils are inorganic clays of lour to medium plasticity. ln addition to day parlides, CL soib may contain a fair amount ol gravel-, sand-, and silt-sized pañicles. The sample tested contained a sizable ptoportion (23.9Yøl of padicles that are sand-sized (#200 Sieve) or larger. Literature suggosts trat medium to stilf CL soils are likely to haw beadng capacities in the nange of 4,000 psf. Recognizing that no specilic beadng capacþ testing was performed, I recommerd that a more conservative bearing capacity of 20(X) psl be used lor design pupos€s. Owr tha years, a number of studiês have been conducted in an effod to correhte scil expansiveness lo atteÈerg llmit data. Acctding to onê stndy, soib with Li¡uirl Umits less than 507o and Plastiefi lndices that þss ü¡an 259å, generally have a low potential lor oxpansion (Snethen, Johnson, and Patrli<, 1977). The scil sample tested was fouttd to have a Lþuid Limlt of 31.3% and a Plasticity lndo< of 8?o. Thus, accotding to tha referenced study, the soil in question is anticipated to have a low expansion potential. lt should be notd that Atterberg Limlts testing does not address mineralogy and ftus may have a limited abilityto reliably predict soil expansi¡n potenthl CL soils often are susceptible to frost heave. Methods should be implemented to lessen he likelihood of frost heave. Foundations should extend to below frost depth or be frost protected by some other means. Water shoJd be kept away from the foundation. Walkways, dfiræways, and ground surûaces should be graded to fbw away from the foundatbn. Gutter down-spout outlets should be kept at least five leet away from the foundation. Vegelaüon requiring signifi,cant watering shurld not be planted near the foundation. No testing was done to datermine üre soil's collapse potential, ln my expelience, foundation failures due to soilcollapse are generally even more catastrophic than failures due to soil expansion. ln every instarrce of soil collapse failu¡B fnt I have investigated, the damagpd home nias located at the mouth of a pronourrced drainage, such as a oan],on or gully where the soil has been deposited alluvially by intermittent runoff water llows. Alluviallydeposited soils are t¡ryically not very dEnse and dedve lheir strengh fiom mipral bonds that form between soll padhles. When trese soils bacome wet, fte mineral bonde dissolve, allowing the scfl pailicles to consolHate (collapse) under any load that is in excess of that wlrich existed wfren the mirpral bonds odginally fomed. ftom (a35FE9-ã{4E * Fox (435p89-¿f¡f85 Enoil : vonceklng@clvcoenginecring.com o Page2 Septsmberll,æí8 Vedfy that the project eite is not at the mouth of any obvlo¡s drainage. lmplementing the aforementioned methods for bwedng tre rbk ol froot heave is also key to leasening lhe dsk of soil collapsefailurc. ln sumrnary, thE soil under the foundat'pn was not specilically læt€d to detErmine its expansiveness brf results of atterberg limits tesling suggest that the eoil has a lour exparsion potential. LikewisE the soil was not specll¡cally tested to determine beadng capacity but was fot¡nd to be ol a t¡pe having draractedetic beadng capacilies in the range ol40@ psf. For dæign puposes, a 2@0 pef bearing capacity is recommended. No specilþ testing uas peilormed to detemine the collapse potenthl ol the soil. The home owner should make wary effort to keep moisture from being infoduced to the soil r¡ear the loundation. Any future purchaser of the home should be apprbed of he undefiing soil characteÈtics and the importarrce of keefiing moisturc away lrcm the foundation. This condudes my report. Please note that this investigation uns performed for the purpose ol prodding general infomation regarding lhe soil undedying the propooed home and makes no plediction of foundational pefomance. This repod should not be regnded as documEntafion of a geotechn¡cal investigation as I am not a geotechnical engineer and this study was not conducted to any çnerally accepted standard ol geotechnknl engineeñng practice, Please contact me if you have questions regading lhis repoil. Sincerel¡ Vance V. King, PE Engineer CIVCO Engineering, lrrc. Enclosure Cc Project File Q, C. Testing. lnc 2944 S 1500 E VERNAL, UTAH 84078 Phone (435) 789-0220 Fax (435) 781-1876 SIEVE ANALYSIS AND ATTEBERG LIMITS CIVCO EnftncerinC - l(lEùç Psredruto, CO 0_ c_ rtsTtNû Projêct No. or Cllenl: Mabdd Type; Dl¡t¡ncc tom CL: lllF= nethra - urilñcd ¡oil da¡¡ific¡lion D.pthr_Oeþ Sempled Tðstccl By MT Stâüoñsl Ddr lÊstod:s/10/2018 A ,9lrot{e¿f.00 Atl¡¡ù¡¡o Lûntl Lhuld l,¡ît 13r.3 Þl¡rüc L¡üh lzt.s Plr¡lé tìda¡l8 Cl[dfr*n ICL - ¡endv Lan thv +4ll,loashrê Oett vlr6t Wt,500 DrvWt,a71,2 H2Ovvt, H2Ota Wâlhèd DryW,127"3 AASHTO T.27 CoffiÊGredalion Savc !Íze We¡ghl Rrl.h R€t. S Tolsl Pæ¡lno Sicw Slzc SDaeg 3! {¡gmml f f $oml t 1.9 lsz.¡ml f.5" 1"esnÌ) 3/4'lrsnml 3t1" 1tr'íz.êtml 1t?. 3/d'¡r.omn¡3/tt' #4 F.?rm'nl t4 -#4 (4.?Jnn¡ WETWT. #4 (t.z¡n¡¡ DRYWT, Tolâl FlnË Gredetion S¡izo Wb¡sht Rst.7o Rct,% Paro Êl (r.zoml 11.4 2.4 97.6 F8{z.nun} Ë10 e.oml 8.9 11 s2 f16 (r rsornl fi2û raæso 11_6 2"4 93,8 il30 toornl F40 f.z5|n)9.0 1,9 91-9 F50 (3oqlrt il6{l rz¡ounl il80 Oærrnl 11ü)nænrl f20O t?ttnì)74.7 {P00 ftsumì 360.3 Total IIrIIIIIII Rcmarks SOLCLASÍ¡IFICATION(trîlltËd)