Designation:D2434–68(Reapproved2006)StandardTestMethodforPermeabilityofGranularSoils(ConstantHead)1ThisstandardisissuedunderthefixeddesignationD2434;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(e)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.1.Scope1.1Thistestmethodcoversthedeterminationofthecoef-ficientofpermeabilitybyaconstant-headmethodforthelaminarflowofwaterthroughgranularsoils.Theprocedureistoestablishrepresentativevaluesofthecoefficientofperme-abilityofgranularsoilsthatmayoccurinnaturaldepositsasplacedinembankments,orwhenusedasbasecoursesunderpavements.Inordertolimitconsolidationinfluencesduringtesting,thisprocedureislimitedtodisturbedgranularsoilscontainingnotmorethan10%soilpassingthe75-µm(No.200)sieve.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyproblems,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D422TestMethodforParticle-SizeAnalysisofSoilsD4253TestMethodsforMaximumIndexDensityandUnitWeightofSoilsUsingaVibratoryTableD4254TestMethodsforMinimumIndexDensityandUnitWeightofSoilsandCalculationofRelativeDensity3.FundamentalTestConditions3.1Thefollowingidealtestconditionsareprerequisitesforthelaminarflowofwaterthroughgranularsoilsunderconstant-headconditions:3.1.1Continuityofflowwithnosoilvolumechangeduringatest,3.1.2Flowwiththesoilvoidssaturatedwithwaterandnoairbubblesinthesoilvoids,3.1.3Flowinthesteadystatewithnochangesinhydraulicgradient,and3.1.4Directproportionalityofvelocityofflowwithhydrau-licgradientsbelowcertainvalues,atwhichturbulentflowstarts.3.2Allothertypesofflowinvolvingpartialsaturationofsoilvoids,turbulentflow,andunsteadystateofflowaretr...
