Designation:D6836−16StandardTestMethodsforDeterminationoftheSoilWaterCharacteristicCurveforDesorptionUsingHangingColumn,PressureExtractor,ChilledMirrorHygrometer,orCentrifuge1ThisstandardisissuedunderthefixeddesignationD6836;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thesetestmethodscoverthedeterminationofsoilwatercharacteristiccurves(SWCCs)fordesorption(drying).SW-CCsdescribetherelationshipbetweensuctionandvolumetricwatercontent,gravimetricwatercontent,ordegreeofwatersaturation.SWCCsarealsoreferredtoassoilwaterretentioncurves,soilwaterreleasecurves,orcapillarypressurecurves.1.2Thisstandarddescribesfivemethods(A-E)fordeter-miningthesoilwatercharacteristiccurve.MethodA(hangingcolumn)issuitableformakingdeterminationsforsuctionsintherangeof0to80kPa.MethodB(pressurechamberwithvolumetricmeasurement)andMethodC(pressurechamberwithgravimetricmeasurement)aresuitableforsuctionsintherangeof0to1500kPa.MethodD(chilledmirrorhygrometer)issuitableformakingdeterminationsforsuctionsintherangeof500kPato100MPa.MethodE(centrifugemethod)issuitableformakingdeterminationsintherange0to120kPa.MethodAtypicallyisusedforcoarsesoilswithlittlefinesthatdrainreadily.MethodsBandCtypicallyareusedforfinersoils,whichretainwatermoretightly.MethodDisusedwhensuctionsnearsaturationarenotrequiredandcommonlyisemployedtodefinethedryendofthesoilwatercharacteristiccurve(thatis,watercontentscorrespondingtosuctions>1000kPa).MethodEistypicallyusedforcoarsersoilswhereanappreciableamountofwatercanbeextractedwithsuctionsupto120kPa.Themethodsmaybecombinedtoprovideadetaileddescriptionofthesoilwatercharacteristiccurve.Inthisapplication,MethodAorEisusedtodefinethesoilwatercharacteristiccurveatlowersuctions(0to80kPaforA,0to120kPaforE)nearsaturationandtoaccuratelyidentifytheairentrysuction,MethodBor...
