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Home My WebLink AboutSubsoil Study€tøerç Huddleston-Berry [,ngineerin¡¡ &. Testing. LLC February 24,2021 Project#02205-0001 Casey Sheets 59 County Road 317 Rifle, Colorado 81650 Subject: Geotechnical Investigation Parcel 217927101002 Silt, Colorado Dear Mr. Sheets, This letter presents the results of a geotechnical investigation conducted by Huddleston-Berry Engineering & Testing, LLC (HBET) at Parcel 217927101002 in Silt, Colorado. The site location is shown on Figure 1. The proposed construction is anticipated to consist of a new single family residence and shop. The scope of our investigation included evaluating the subsurface conditions at the site to aid in developing foundation recommendations for the proposed construction and to evaluate the site soils for onsite wastewater treatment. Site Conditions At the time of the investigation, a small out-building was located in the northern portion of the site. The remainder of the site was open. The site sloped down towards the southwest. Vegetation consisted of weeds, grasses, and small to large bushes. The site was bordered to the north, west, and east by open land, and to the south by Alta Mesa Road. Subsurface Investigation The subsurface investigation included four test pits as shown on Figure 2. The test pits were excavated to depths ranging from 3.0 to 9.0 feet below the existing ground surface. Typed test pit logs are included in Appendix A. As indicated on the logs, the subsurface conditions at the site were fairly consistent. The test pits encountered 1.0 foot of topsoil above brown, moist, stiff sandy lean clay soils to the bottoms of the respective excavations. However, Test Pit TP-z, conducted in the eastern portion of the investigated area, encountered trace gravels in the sandy lean clay soils. Groundwater was not encountered at the time of the investigation. Laboratory Testins Laboratory testing was conducted on samples of the native soils encountered in the test pits. The testing included grain size analysis, Atterberg limits determination, natural moisture content and density determination, swell/consolidation testing, and maximum dry density and optimum moisture content (Proctor) determination. The laboratory testing results are included in Appendix B. 2789 fuverside Parkway Grand Junction, Colorado 81501 Phone: 970-255-8005 Info @huddlestonberry. com Parcel217927l0l002 #02205-0001 o2l24l2t Húddleston-B€rry tn¿inc¡ringñ lcnìn!, I L( The laboratory testing results indicate that the native soils are slightly plastic. In addition, the native soils were shown to be slightly collapsible, with up to approximately 2.0o/o collapse measured in the laboratory. f,'oundation Recommendations Based upon the results of the subsurface investigation and nature of the proposed construction, shallow foundations are recommended. Spread footings and monolithic (turndown) structural slabs are both appropriate foundation alternatives. However, the native soils are slightly collapsible. Therefore, in order to provide a stable bearing stratum and limit the potential for excessive differential movements, it is recommended that the foundations be constructed above a minimum of 24-inches of structural fill. The native soils, exclusive of topsoil, are suitable for reuse as structural fill. Imported structural fillshouldconsistofagtanular,non-expansive,49!@!ggmaterialapprovedbyHBET. For spread footing foundations, the footing areas may be trenched. However, for monolithic slab foundations, the structural fill should extend across the entire building pad arca to a depth of 24- inches below the lowest portion of the foundation. Structural fill should extend laterally beyond the edges ofthe foundation a distance equal to the thickness ofstructural fill forboth foundation types. Prior to placement of structural fill, it is recommended that the bottom of the foundation excavation be scarified to a depth of 6 to 9 inches, moisture conditioned, and compacted to a minimum of 95o/o of the standard Proctor maximum dry density, within L 2o/o of the optimum moisture content as determined in accordance with ASTM D698. Structural fill should be moisture conditioned, placed in maximum 8-inch loose lifts, and compacted to a minimum of 95o/o of the standard Proctor maximum dry density for fine grained soils and 90%o of the modified Proctor maximum dry density for coarse grained soils, within t 2o/o of the optimum moisture content as determined in accordance with ASTM D698 and D1557, respectively. Structural fill should be extended to within 0.l-feet of the bottom of the foundation. No more than O.l-feet of gravel should be placed below the footings or turndown edge as a leveling course. For structural fill consisting of the native soils or imported granular materials and foundation building pad preparation as recommended, a maximum allowable bearing capacíty of 1,500 psf may be used. In addition, a modulus of subgrade reaction of 150 pci may be used for structural fill consisting of the native soils and a modulus of 200 pci may be used for approved imported structural fill. Foundations subject to frost should be at least 24-inches below the finished grade. Any stemwalls or retaining walls should be designed to resist laterul earth pressures. For backf,rll consisting of the native soils or imported gtanular, non-free draining, non-expansive material, we recommend that the walls be designed for an active equivalent fluid unit weight of 45 pcf in areas where no surcharge loads are present. An at-rest equivalent fluid unit weight of 65 pcf is recommended for braced walls. LateruI earth pressures should be increased as necessary to reflect any surcharge loading behind the walls. 2P:9008 ALL PROJECTS\02205 - Casey Sheets\02205-0001 Pucel217927101002\200 - Geo\02205-0001 LR02232l.doc Parcel2l79277OlO02 #02205-0001 02/24121 Huddleston-Børy t¡E¡n.c!¡og¡ lc{i¡g, l,L(' Water soluble sulfates are common to the soils in Western Colorado. Therefore, at a minimum, Type I-II sulfate resistant cement is recommended for consfuction at this site. Non-Structural Floor Slab and Exterior Flatwork Recommendations In order to reduce the potential for excessive differential movements, it is recommended that non-structural floating floor slabs be constructed above a minimum of 18-inches of structural fill with subgrade preparation, structural fill materials, and fill placement be in accordance with the Foundatíon Recommendations section of this report. It is recommended that exterior flatwork be constructed above a minimum of l2-inches of structural fill. Drainage Recommendations Gradíns snd drainøse are critical for the lone-term oerformance of the structure and grading around the structure should be designed to carry precipitation and runoff away from the structure. It is recommended that the finished ground surface drop at least twelve inches within the first ten feet away from the structures. It is also recommended that landscaping within five feet of the structures include primarily desert plants with low water requirements. In addition, it is recommended that irrigation, including drip lines, within ten feet of foundations be minimized. HBET recommends that surface downspout extensions be used which discharge a minimum of 15 feet from the structures or beyond the backfill zones, whichever is gteater. However, if subsurface downspout drains are utilized, they should be carefully constructed of solid-wall PVC and should daylight a minimum of 15 feet from the structures. In addition, an impermeable membrane is recommended below subsurface downspout drain lines. Dry wells should not be used. As discussed previously, gtoundwater was not encountered at the time of the investigation. However, perimeter foundation drain is recommended to limit the potential for surface moisture to impact the structures. In general, the perimeter foundation drains should consist of prefabricated drain materials or perforated pipe and gravel systems with the flowlines of the drains at the bottoms of the foundations (at the highest point). The perimeter drains should slope at a minimum of 1.%o to daylight or to sumps with pumps. An impermeable membrane is also recommended at the base of the drains to limit the potential for moisture to infiltrate into the subsurface below the foundations. Onsite Wastewater Treatment Svstem Feasibilitv In order to evaluate the site soils for onsite wastewater treatment, percolation testing was conducted at the site in accordance with Garfield County regulations. The percolation rate in the native soils was determined to be approximately 12 minutes-per-inch. The percolation testing dataarc included in Appendix C. In accordance with Garfield County regulations, a percolation rate of between 5 to 60 minutes- per-inch is required for soils to be deemed suitable for onsite wastewater treatment. Therefore, based upon the results of the percolation testing, HBET believes that the native soils are suitable for onsite wastewater treatment. 3P:\2008 ALL PROJECTS\02205 - Casey Sheets\02205-0001 Pæcel217927101002\200 - Geo\02205-0001 LR02232l.doc Parcet217927101002 #02205-0001 02/24/21 Huddlcston-Belft' tr8im.¡ingA t.{¡nß, l-L(' In addition to the percolation rate of the subsurface materials, the seasonal high groundwater elevation is an important factor in determining the suitability of the site for Onsite Wastewater Treatment Systems. For OWTS suitability, the seasonal high groundwater elevation should be at least four feet below the bottom of the proposed absorption bed. As discussed previously, gtoundwater was not encountered at the time of the investigation. In general, based upon the results of the substrface investigations, HBET believes that the seasonal high groundwater level is deeper than 8.0 feet below the existing grade at this site. General Notes The recommendations included above are based upon the results of the subsurface investigation and on our local experience. These conclusions and recommendations are valid only for the proposed construction. As discussed previously, the subsurface conditions encountered in the test pits were fairly consistent. However, the precise nature and extent of any subsurface variability may not become evident until construction. As a result, it is recommended that HBET provide construction materials testing and engineering oversight during the entire construction process. It ís important to note thøt the recommendations hereín øre intended to reduce the risk of structaral movement ønd/or damøge, to vsrvíng desrees, assocíated wìth volame chanse of the natìve soìls. However. HBET cannot oredíct lonp-term changes in subsurface moísture conditìons and/or the orecìse maenitude or erteü of volume chanse ín the native soíls. ÍYhere sisnif¡cønt increøses in subsurface moísture occur due to poor srading, ímorooer stormh,ater mønøeement. utíIítv line failure, excess irrìgøtíon, or other cøuse, either durìng construct¡on or the result of øctions of the oropertv owner, several inches of movement øre oossible. b øddítion, anv failure to comolv wíth the recommendøtions ín this reoort releases Hudd.leston- Berrv Ensíneerins & Testins, LLC of anv líahilitv with resard to the structure performance. We are pleased to be of service to your project. Please contact us if you have any questions or comments regarding the contents of this report. Respectfully Submitted: Huddleston-Berry Engineering and Testing, LLC Michael A. Berry, P.E. Vice President of Engineering 4P:\2008 ALL PROJECTS\02205 - Cæey Sheets\02205-0001 Pxcel217927l0l002\200 - Geo\02205-0001 LR02232l.doc FIGURES Garfield Coun4tij2312021Garfield County Land ExplorerGsrfield County Coiorsdo Land frxplorer q O .4 I åPrintpeFIGT]RE 1Location MapcopycsvPDFPrintSeorch: IOwnerResullsPorcelPhysicolAddress! I-auets!l aaministrative Boundaries! rns & subdivisions! nrrn now! water FeaturesSeorch217927101002DrowBufferL$wåflsSHEETS, CASEYADAM & DUSWLEAH33I COUNTY RDSILTZoningMeosureLocoteBosemophttps ://maps.garfi eld-counÇ.com/landexplorer/1t1 {ìntftcld Conn4,2t23t2021Garfield County Land Explorer.*.*q o.4 I Ê.! Ç-qPrint,t*'t.' . rr*frLtt,"tryI/t\frI'I' rlItCopy CSV PDF PrintSeorch:OwnerResullsPorcelPhysicolAddressSHEETS, CASEYADAM & DUSTYLEAH21792710100233I COUNÏY RDSILÏng I to I of 'l entriesPrevious I NexlLongitude: -107.644350, Lotitude: 39.50ó7 52BosemopgvSeorchBufferDrowLcyersMeosure1*,Ç1t1https ://maps. garfield-county.com/landexplorer/Site Plan APPENDIX A Typed Test Pit Logs GEOTECH BH COLUMNS 02205-OOOI21212312'l!7toLmc'zc=trmuoNNo(¡oooc'trmz-{o¡)øoU'fooø\Õaìl\JÞioat æx.r- ö þFVzä.flæ5 (ì oasä ?60 0w.FOEC);"<o+gjæ..<oa;E F'oäûoFj3seF4Fa)!aoLm(l5clìozqF-oo!vPm()2Þ=m!0¡ãoN\¡(oN\¡oooN+mU,+!{zc=trmn{!¡Il,omo'llzo-{mu,5Poo83PãØ=tr'm{+oE,mxC)Þızooz1ô-{o7IT'4.oEmU,{v{moorN-{ıox@o¡oxJooc'¡moxmE,ETDoo=!m-{mo(¡Ir¡-o7o3il8fiHEìãËHHr9ı,22o7oc=E'mm{ızo.¿CL?m(t{!LNnroDEPTH(ft)GRAPHICLOG-{m7t-omU)oÐ1tIozSAMPLE ryPENUMBERRECOVERY %(ROD)BLOWCOUNTS(N VALUE)POCKET PEN(tsÐDRY UNITWT(pcÐMOISTURECoNTENT (%)I- -'l=s-{ tDØmnoFINES CONTENT(Y.)LIQUIDLIMITPLASTICLIMITPLASTICITYINDEXl\'(¡ìr'l¡'11lÍ!. t/_, J\ ..t/_aÞoUt0tJo.É.Joıq)fı'ø-{o!Øot-t-0¡oQ0)ØØáooo(DØÐfo.t-oÂtfoçc)t-vuð{-f39.(nFu,4-ãos\¡\¡f¡o(s-o@l\JNot(¡o(rt(Doo3ooott0)foooo GEOTECH BH COLUMNSGINT US LAB.GDT 2/23121!ãPmo-{zc=Emvol\)NoOlooo()1lolottøloFIU,t5\o{o$æa=oooæoNF-l=æ=\oËãöà7dwiroF€+ErsË.<too0qR"Èo'!'scr'¡Fô!1P¡nooclIızqFoo!vIm()z=m!0tC)oN\¡(oN\¡oooN)+mU,{!{zc=trmn{!IN!omo.Ttzo-{mØ5PG¡o9¿c,ll.qËU'=om-{totrmxo{ızooz{-cloFIT'noE,mU,{Þ7{mo(lNIıc)x5(Do)C,xtooo-mo-mo@TDoo=.om{IttE,(¡No7ottl=És=ãXeHiãiHHr 9ı,aZovoczE'mm{ızo.¿CL¿nrø{!{r4,NhrccDEPTH(ft)GRAPHICLOG-.1mÐr-ImØo7!-.{ozSAMPLE TYPENUMBERRECOVERY %ßaD)BLOWCOUNTS(N VALUE)POCKET PEN(tsf)DRY UNITWT(pcîMOISTURECoNTENT (%)I- -'l=s-.{ @u) fnvoFINES CONTENT(%)LIQUIDLIMITPLASTICLIMITPLASTICITYINDEXl.'¿'. rs. l",/-'-.{ç.'6 '-l*.! . I/,. '\ . .t,_oÂtoU'o)CLÉ.eoð0):t.oØ-to!U,I|_(t,qtfCLt-o0tfoçÉ.Jlno3oonmt-(t,ovctı€_f39.ØJ+o-iqtoo3ooøp.A)soooo GEOTECH BH COLUMNS O22OS,OOOI PARCEL 217927101002.GPJ GINT US LAB.GDT!7PmC){zc=EmFloININlol9lôlolot-omzoA)Øo(nJooø€^ì.Jìro05 æ=.'- 5 EFq:rdã'ó05 (Ù oacä ?GO AWJJOEO o"{v)ígræ<ûo;E E'o¡öûaR"ÈomFa)!7Pm()5oIızq.äo!7PmC)z=m!ttool\){(ot\)\¡oooN{mU,{!{zc=-EÈmitn-{qP- (.tzomat5PG¡O83PË(tt =om-{IoE,mxC)Þ{ızooz{uç)-{o7Iî'4.oo-{matvlllc'(,lNoIm()xmE,ETD-{ıo;F=@0¡oxJoooo=!mmoOlNonotìt=*Ë#ÍãH9SãiiHi 29oztoCzE,mmIo2CL¿CLe-{mat{!-vtNmoDEPTH(ft)GRAPHICLOG{mnFt-gmU)onTIo2SAMPLE TYPENUMBERRECOVERY %(ROD)BLOWCOUNTS(N VALUE)POCKET PEN.(ts0DRY UNITWT(pcÐMOISTURECoNTENT (%)¡--l=s{c!utmnoFINES CONTENT(%)LIQUIDLIMITPLASTICLIMITPLASTICITYINDEX/) .t\-.. .tt¿' tj ..¿. rs.. t,,¡ ,¡:- .1.: . y; l¡. ¡;¡..t*;.r!. t/. j\ .t/,o0,oa,0)5o.É.Jo@0to-an-1o!ØIl-Àl."l"Ø0¡fCLt-og¡Jot-()vqıÉ-f39.an5+ØÉ+@oo3ooØp.ÐÈoooa+ BH COLUMNS O22O$'OOO1 PARCEL 217927,IO1OO2.GPJ GINT US LAB.GDT!7Pmc,zC=Em7oNNo(tloo<fotrmzoÂ)Øoa,ooû\O aì }.J Þr'!o!ú æx-r- 5 e=q::r!ã'cto!' (l 0acä ?bo ÀwJãOEô o"c4o+Þæ.<ûaGE F'oàËË.ooFÈogeFa)!7oLnro5c'Iozq.n-oo!7Pnr()z=m!Â,ðoN{(oN{oooN{mU,{!{zc=EmÐ{!I5!omo'nqãtsnoEmxC)Þjoz=m-{IoE,+ıoxJTD0)o-oomx6)2ız()ozuC){o7Iî'4.oE'-{mat,{v{mE'ENØ0oTmoxmoETDoo=!m{mE'('lNo7orilEÊHEñËiHHr9ı,22ovoCzommÞIozo.zCL¿ntan!-{U,NnrcDEPTH(ft)GRAPHICLOG{m7t-om(to4.!IozSAMPLE TYPENUMBERRECOVERY %(ROD)BLOWCOUNTS(N VALUE)POCKET PEN(tsf)DRY UNITWT(pc0MOISTURECoNTENT (%)I--l=i-{ TDømnoFINES CONÏENT(Yo)LIQUIDLIMITPLASTICLIMITPLASTICITYINDEX.rì;. ¡/j..1\-...1/>.J\l ..r-. r:.. l,r.ki...ri-..lr-..Lì ..f-: .r.:. j-f .'.rsìf¡ f//. r\. .t'P .t\ . t¿-. )\ . .taa0,oU'À)CLÉ.oðotJ.oø-{o!U'It-(¡tl-at0)Jo.t-oq)Joçc,vqı€-f39.ø.r+ø=+IDoo3ootnp.q)s,,oooîà APPENDIX B Laboratory Testing Results Huddleston-Berry Engineering & Testing, LLC 2789 Riverside Parkway Crrand Junctioru CO 81501 970-255-8005 ATTERBERG LIMITS' RESULTS CLIENT Casev Sheets PRO.JEGT lllAME Parcel 217927101002 PROJECT NUMBER 02205-0001 PROJECT LOCATION s¡tr eo @ P L A s T I c I T I N D E X 50 40 30 20 l0 CL.ML @ 0 20 60 LIQUID LIMIT 80 r00 Specimen ldentification LL PL PI #200 Classification a TP-í, GB-l 1t15 25 15 t0 5l SANDY LEAN C|-AY(CL) N N Þôq EI U)l Fzo Àoñoo o ÈNoÈ N J IJJoÉ À ooo @eNNo 6Þ =Jo É,U6tUÞF o FN È N JU(J ú. À ooo @oNNo IJJNoz É.o Huddleston-Berry Engineering & Testing, LLC 2789 Rivøside Parkway Grand Junctior\ CO 81501 970-255-8005 GRAIN SIZE DISTRIBUTION CLIENT Casev Sheets PROJECT ]llAllE Parcel 217927101002 PROJ ECT NUMBER 02205-0001 PR(NECT LOCATION SiIt, CO U.S. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS I3 4 6 810 l4t6 20 30 40 50 60 100140200 HYDROMETER 6 1 1 Þ IIul =d¡ É LrJztr Fz uJoÉtrlô- 100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0 I I I \L -t I t : \t 100 10 0.001 GRAIN SIZE IN MILLIMETERS COBBLES GRAVEL SAND SILT OR CLAY coarse fine coarse medium fine Specimen ldentification Classification LL PL PI Cc Cu o TP-1, GB-l 1n5 SANDY LEAN CLAY(CL)25 t5 t0 Specimen ldentification D100 DôO D30 D10 YoGravel %Sand %sitt %Clay o TP-1, GB-l 1115 9.5 o.129 4.8 4.2 51.1 Huddleston-Berry Engineering & Testing, LLC 2789 Riverside Parkway Crrand Junctioq CO 81501 970-255-8005 MOISTU RE.DENS¡TY RELATIONSHI P PROJECT NUMBER O22O5.OOO1 PROJECT NAME Parcel 217927101002 PR(UECT LOCAilON sitf eô CLIENT Casev Sheets ¡Ul \ \ \ \ \ \ \ \ \ \ // // // Sample Date: Sample No.: Source of Material: Description of Material 1t1il2021 GB.1 145 TP-I SANDY LEAN CLAY(CL) Test Method ASTM D698A 140 135 TEST RESULTS Maximum Dry Density 118.0 PCF Optimum Water Content 12'O % 130 125 GRADAÏON RESULTS (% PASSTNG) #200 #4 314" 5t 95 100 o CLtt-6z UJo É.o ATTERBERG LIMITS 1 20 LL 25 PL PI 15 l0 115 Curves of 10lo/o Saturation for Specific Gravity Equal to 2.80 110 2.70 2.60 105 100 95 90 5 15 WATER CONTENT, % 0 l0 20 25 30 NèN N Foq EI a)ft- =o 0-oñoo o FNoF NJt!o É. c oooooNNo z4 É.Þ(Í, JoØzo(,) Huddleston-Berry Engineering & Testing, LLC 2789 Riverside Parkway Crrand Junctio4 CO 81501 970-2s5-8005 CONSOLIDATION TEST CLIENT Casev Sheets PROJECT NAIIE Parcel 217927 101OO2 PRGIECT NUMBER PROJECT LOCATION SiIt, CO 2.0 2.5 3.0 3.5 4.0 4.5 5.0 s ¿ tFØ 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0 r00 1,000 STRESS, psf Specimen ldentification Ta MC% 7 I ) I \ \ \ \ \ \ \ \ \ \ \ \ o TP-1, MC-t 2.0 Classification 104 APPENDIX C Percolation Testing Results PERCOLATION TESTING Project Name:Parcel 217927101002 Location: Silt, CO Testing Conducted By:S. Dinterman Supervising Engineer:M. Berry Pit Dimensions: Length Water Level Depth SOIL PROFILE Test Number:I Top of Hole Depth: 4ft Diameter of Hole: 4-in. Depth of Hole 17-in. Time (min.) Water Depth (in.) Change (in.) 0 1j25 5 1.875 0.75 10 2.5 0.625 15 3j25 0.625 20 3.75 0.625 25 4.25 0.5 30 4.75 0.5 35 5.25 0.5 40 5.75 0.5 45 6.25 0.5 50 6.5 o.25 55 7 0.5 60 7.25 o.25 12Rate (min/in): ; Width Not Encountered X Test Number: Top of Hole Depth: Diameter of Hole: Depth of Hole Depth 4.0 ft Remarks Test Number: Top of Hole Depth: Diameter of Hole: Depth of Hole: 0-1 ft Glavev Sand with Orqanics fiOPSOIL) 1-4ft Sandv Lean CLAY (CL), brown, moist, stiff Time (min.) Water Depth (in.) Change (in.) Time (min.) Water Depth (in.) Change (in.) Average Percolation Rate (min/in) Rate (min/in)Rate (min/in) PERCOLATION TESTING Project Name:Parcel 217927'101002 Location: Si co Testing Conducted By S. Dinterman Supervising Engineer:M. Berry ; WidthPit Dimensions: Length Water Level Depth SOIL PROFILE n Test Number: Top of Hole Depth: 3 ft Diameter of Hole: 7-in. Not Encountered X Test Number: Top of Hole Depth: Diameter of Hole: Depth 3.0 ft Remarks Test Number: Top of Hole Depth: Diameter of Hole: Depth of Hole:Depth of Hole: Time (min.) Water Depth (in.) Change (in.) 0 1125 5 't.875 0.75 10 2.5 0.625 15 3j25 0.625 20 3.75 0.625 25 4.25 0.5 30 4.75 0.5 35 5.25 0.5 40 5.75 0.5 45 6.25 0.5 50 6.5 o.25 55 7 0.5 60 7.25 o.25 12Rate (min/in): ïî-rn Depth of Hole: 1 TP-4 ect Pit No. 111512021 Clavev Sand with Orqanics (TOPSOIL)0-1 ft 1-3 ft Sandv Lean CLAY (CL), brown, moist, stiff Time (min.) Water Depth (in.) Change (in.) Time (min.) Water Depth (in.) Change (in.) Average Percolation Rate (min/in) Rate (min/in)Rate (miniin)