Designation:D7664−10(Reapproved2018)´1StandardTestMethodsforMeasurementofHydraulicConductivityofUnsaturatedSoils1ThisstandardisissuedunderthefixeddesignationD7664;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ε1NOTE—ReapprovalwithchangeseditoriallyaddedinOctober2018.1.Scope1.1Thesetestmethodscoverthequantitativemeasurementofdatapointssuitablefordefiningthehydraulicconductivityfunctions(HCF)ofunsaturatedsoils.TheHCFisdefinedaseithertherelationshipbetweenhydraulicconductivityandmatricsuctionorthatbetweenhydraulicconductivityandvolumetricwatercontent,gravimetricwatercontent,orthedegreeofsaturation.Darcy’slawprovidesthebasisformeasurementofpointsontheHCF,inwhichthehydraulicconductivityofasoilspecimenisequaltothecoefficientofproportionalitybetweentheflowrateofwaterthroughthespecimenandthehydraulicgradientacrossthespecimen.TodefineapointontheHCF,ahydraulicgradientisappliedacrossasoilspecimen,thecorrespondingtransientorsteady-statewaterflowrateismeasured(orviceversa),andthehydraulicconductivitycalculatedusingDarcy’slawispairedwithindependentmeasurementsofmatricsuctionorvolumet-ricwatercontentinthesoilspecimen.1.2ThesetestmethodsdescribeafamilyoftestmethodsthatcanbeusedtodefinepointsontheHCFfordifferenttypesofsoils.Unfortunately,thereisnosingletestthatcanbeappliedtoallsoilstomeasuretheHCFduetotestingtimesandtheneedforstresscontrol.Itistheresponsibilityoftherequestorofatesttoselectthemethodthatismostsuitableforagivensoiltype.Guidanceisprovidedinthesignificanceandusesectionofthesetestmethods.1.3SimilartotheSoilWaterRetentionCurve(SWRC),definedastherelationshipbetweenvolumetricwatercontentandmatricsuction,theHCFmaynotbeauniquefunction.BoththeSWRCandHCFmayfollowdifferentpathswhethertheunsaturatedsoilisbeingwettedordried.Atestmethodshouldbeselectedwhichreplicates...
