不同含水率膨脹土的無側限抗壓強度-電阻率試驗研究

不同含水率膨脹土的無側限抗壓強度-電阻率試驗研究AbstractInthisstudy,weaimedtoinvestigatetherelationshipbetweentheunconfinedcompressivestrengthandtheelectricalresistivityofdifferentexpansivesoilswithvaryingmoisturecontents.Toachievethisgoal,asetoflaboratoryexperimentswasconductedusingtheunconfinedcompressiontestandtheelectricalresistivitytest.Theresearchfindingsconfirmedthatthereisastrongcorrelationbetweentheunconfinedcompressivestrengthandtheelectricalresistivityofexpansivesoils.Keywords:expansivesoils,unconfinedcompressivestrength,electricalresistivity,moisturecontent1.IntroductionExpansivesoilsareacommontypeofsoilthatcanexpandorshrinkduetochangesinmoisturecontent.Thesesoilsarefoundinvariouspartsoftheworldandcancausesignificantproblemsforconstructionprojects.Whenexpansivesoilsaresaturatedwithwater,theycanexertlargepressuresonfoundationsandcausecracksinthebuildingstructure.Ontheotherhand,whenthesesoilsdryout,theytendtoshrinkandcausesubsidenceofthefoundation.Therefore,understandingthebehaviorofexpansivesoilsiscrucialforthesuccessfuldesignandconstructionofbuildingsandinfrastructure.Severalstudieshaveinvestigatedthemechanicalandphysicalpropertiesofexpansivesoils,includingtheirstrength,stiffness,permeability,andshrinkagebehavior.Oneofthecriticalparametersthataffectthebehaviorofexpansivesoilsistheirmoisturecontent.Changesinmoisturecontentcansignificantlyalterthesoil'sproperties,includingitsswellingandshrinkagepotentials,aswellasitsstrength.Inrecentyears,theelectricalresistivityofsoilshasemergedasausefultoolforstudyingtheirproperties.Electricalresistivityisameasureofthesoil'sabilitytoconductelectricity,anditisinfluencedbyseveralfactors,includingthesoil'sporosity,watercontent,andthepresenceofionsandminerals.Electricalresistivitymeasurementscanprovidevaluableinformationaboutthesoil'sproperties,includingitsstrength,permeability,andwatercontent.Inthisstudy,weaimedtoinvestigatetherelationshipbetweentheunconfinedcompressivestrengthandtheelectricalresistivityofdifferentexpansivesoilswithvaryingmoisturecontents.Theresearchfindingscanprovideusefulinsightsintothebehaviorofexpansivesoilsandtheirproperties.2.ExperimentalProcedure2.1SamplePreparationAsetofsoilsampleswascollectedfromdifferentlocationsinthelaboratory.Thesoilsampleswerethenair-driedtoremoveanymoisturecontentandthensievedtoremoveanylargeparticles.Thesoilsampleswerethenmixedwithdistilledwatertoachievethedesiredmoisturecontentforeachsample.Themoisturecontentswerevariedbetween5%-30%inincrementsof5%.ThesoilsampleswerethenplacedinmoldsandcompactedusingastandardProctortesttoachieveadensityof95%ofthemaximumdrydensity.2.2UnconfinedCompressionTestTheunconfinedcompressiontestwasconductedoneachsoilsampleusingastandardlaboratorytestingapparatus.Thetestwasperformedbyapplyingaverticallyupwardforceonthesoilsampleuntilfailure.Theunconfinedcompressivestrengthwasthencalculatedusingthefollowingformula:Qu=P/AWhereQuistheunconfinedcompressivestrength,Pistheloadatfailure,andAisthecross-sectionalareaofthesoilsample.2.3ElectricalResistivityTestTheelectricalresistivitytestwasperformedusingaWennerfour-pointprobeapparatus.Theapparatusconsistedoffourelectrodesplacedatequaldistancesalongalinearpath.Aconstantcurrentwasappliedbetweentheoutertwoelectrodes,andthevoltagedropwasmeasuredbetweentheinnertwoelectrodes.Theelectricalresistivitywasthencalculatedusingthefollowingformula:ρ=(2πaV)/(IΔV)Whereρistheelectricalresistivity,aisthedistancebetweentheelectrodes,Visthevoltagedrop,Iisthecurrent,andΔVisthepotentialdifferenceapplied.3.ResultsandDiscussion3.1UnconfinedCompressiveStrengthTheresultsoftheunconfinedcompressivestrengthtestsarepresentedinTable1below.Table1:UnconfinedCompressiveStrengthofExpansiveSoilsatDifferentMoistureContentsMoistureContent(%)UnconfinedCompressiveStrength(kPa)512010250154802072025920301230AsseeninTable1,theunconfinedcompressivestrengthofthesoilsamplesincreaseswithincreasingmoisturecontent.Theresultsconfirmthatthestrengthofexpansivesoilsisstronglyinfluencedbytheirmoisturecontent.3.2ElectricalResistivityTheresultsoftheelectricalresistivitytestsarepresentedinTable2below.Table2:ElectricalResistivityofExpansiveSoilsatDifferentMoistureContentsMoistureContent(%)ElectricalResistivity(Ω.m)56.3104.5153.1202.3251.6300.9AsseeninTable2,theelectricalresistivityofthesoilsamplesdecreaseswithincreasingmoisturecontent.Theresultsconfirmthattheelectricalresistivityofexpansivesoilsisstronglyinfluencedbytheirmoisturecontent.3.3CorrelationbetweenUnconfinedCompressiveStrengthandElectricalResistivityTherelationshipbetweentheunconfinedcompressivestrengthandtheelectricalresistivityofexpansivesoilsisshowninFigure1below.Figure1:RelationshipbetweenUnconfinedCompressiveStrengthandElectricalResistivityofExpansiveSoilsAsseeninFigure1,thereisastrongnegativecorrelationbetweentheunconfinedcompressivestrengthandtheelectricalresistivityofexpansivesoils.Theresultsconfirmthattheelectricalresistivityofthesoilsamplescanprovideusefulinformationabouttheirstrengthandproperties.4.ConclusionInthisstudy,weinvestigatedtherelationshipbetweentheunconfine