【astm標準】d 2434 - 68 (2006)

1、Designation:D2434–68(Reapproved2006)StardTestMethodfPermeabilityofGranularSoils(ConstantHead)1ThisstardisissuedunderthefixeddesignationD2434thenumberimmediatelyfollowingthedesignationindicatestheyearofiginaladoptioninthe

2、caseofrevisiontheyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperepsilon(e)indicatesaneditialchangesincethelastrevisionreapproval.ThisstardhasbeenapprovedfusebyagenciesoftheDepartmentofDefen

3、se.1.Scope1.1Thistestmethodcoversthedeterminationofthecoefficientofpermeabilitybyaconstantheadmethodfthelaminarflowofwaterthroughgranularsoils.Theprocedureistoestablishrepresentativevaluesofthecoefficientofpermeabilityof

4、granularsoilsthatmayoccurinnaturaldepositsasplacedinembankmentswhenusedasbasecoursesunderpavements.Indertolimitconsolidationinfluencesduringtestingthisprocedureislimitedtodisturbedgranularsoilscontainingnotmethan10%soilp

5、assingthe75m(No.200)sieve.1.2Thisstarddoesnotpurpttoaddressallofthesafetyproblemsifanyassociatedwithitsuse.Itistheresponsibilityoftheuserofthisstardtoestablishappropriatesafetyhealthpracticesdeterminetheapplicabilityofre

6、gulatylimitationspritouse.2.ReferencedDocuments2.1ASTMStards:2D422TestMethodfParticleSizeAnalysisofSoilsD4253TestMethodsfMaximumIndexDensityUnitWeightofSoilsUsingaVibratyTableD4254TestMethodsfMinimumIndexDensityUnitWeigh

7、tofSoilsCalculationofRelativeDensity3.FundamentalTestConditions3.1Thefollowingidealtestconditionsareprerequisitesfthelaminarflowofwaterthroughgranularsoilsunderconstantheadconditions:3.1.1Continuityofflowwithnosoilvolume

8、changeduringatest3.1.2Flowwiththesoilvoidssaturatedwithwaternoairbubblesinthesoilvoids3.1.3Flowinthesteadystatewithnochangesinhydraulicgradient3.1.4Directproptionalityofvelocityofflowwithhydraulicgradientsbelowcertainval

9、uesatwhichturbulentflowstarts.3.2Allothertypesofflowinvolvingpartialsaturationofsoilvoidsturbulentflowunsteadystateofflowaretransientinacteryieldvariabletimedependentcoefficientsofpermeabilitytherefetheyrequirespecialtes

10、tconditionsprocedures.4.Apparatus4.1PermeametersasshowninFig.1shallhavespecimencylinderswithminimumdiametersapproximately812timesthemaximumparticlesizeinaccdancewithTable1.Thepermeametershouldbefittedwith:(1)apousdisksui

11、tablereinfcedscreenatthebottomwithapermeabilitygreaterthanthatofthesoilspecimenbutwithopeningssuff?cientlysmall(notlargerthan10%finersize)topreventmovementofparticles(2)manometeroutletsfmeasuringthelossofheadhoveralength

12、lequivalenttoatleastthediameterofthecylinder(3)apousdisksuitablereinfcedscreenwithaspringattachedtothetopanyotherdevicefapplyingalightspringpressureof22to45N(5to10lbf)totalloadwhenthetopplateisattachedinplace.Thiswillhol

13、dtheplacementdensityvolumeofsoilwithoutsignificantchangeduringthesaturationofthespecimenthepermeabilitytestingtosatisfytherequirementprescribedin3.1.1.4.2ConstantHeadFilterTankasshowninFig.1tosupplywatertoremovemostofthe

14、airfromtapwaterfittedwithsuitablecontrolvalvestomaintainconditionsdescribedin3.1.2.NOTE1—Deairedwatermaybeusedifpreferred.1ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoilRockisthedirectresponsibilityofSubcom

15、mitteeD18.04onHydrologicPropertiesHydraulicBarriers.CurrenteditionapprovedFeb.12006.PublishedMarch2006.iginallyapprovedin1965.Lastpreviouseditionapprovedin2000asD2434–68(2000).2FreferencedASTMstardsvisittheASTMwebsitewww

16、.astm.gcontactASTMCustomerServiceat.FAnnualBookofASTMStardsvolumeinfmationrefertothestard’sDocumentSummarypageontheASTMwebsite.1Copyright?ASTMInternational100BarrHarbDrivePOBoxC700WestConshohockenPA194282959UnitedStates.

17、5.3Fromthematerialfromwhichtheoversizehasbeenremoved(see5.2)bythemethodofquarteringasampleftestingequaltoanamountapproximatelytwicethatrequiredffillingthepermeameterchamber.6.PreparationofSpecimens6.1Thesizeofpermeameter

18、tobeusedshallbeasprescribedinTable1.6.2Makethefollowinginitialmeasurementsincentimetressquarecentimetresrecdonthedatasheet(Fig.3)theinsidediameterDofthepermeameterthelengthLbetweenmanometeroutletsthedepthH1measuredatfour

19、symmetricallyspacedpointsfromtheuppersurfaceofthetopplateofthepermeabilitycylindertothetopoftheupperpousstonescreentemparilyplacedonthelowerpousplatescreen.Thisautomaticallydeductsthethicknessoftheupperpousplatescreenfro

20、mtheheightmeasurementsusedtodeterminethevolumeofsoilplacedinthepermeabilitycylinder.Useaduplicatetopplatecontainingfourlargesymmetricallyspacedopeningsthroughwhichthenecessarymeasurementscanbemadetodeterminetheaverageval

21、uefH1.CalculatethecrosssectionalareaAofthespecimen.6.3Takeasmallptionofthesampleedasprescribedin5.3fwatercontentdeterminations.Recdtheweightoftheremainingairdriedsample(see5.3)W1funitweightdeterminations.6.4Placetheprepa

22、redsoilbyoneofthefollowingproceduresinunifmthinlayersapproximatelyequalinthicknessaftercompactiontothemaximumsizeofparticlebutnotlessthanapproximately15mm(0.60in.).6.4.1Fsoilshavingamaximumsizeof9.5mm(3?8in.)lessplacethe

23、appropriatesizeoffunnelasprescribedin4.3inthepermeabilitydevicewiththespoutincontactwiththelowerpousplatescreenpreviouslyfmedlayerfillthefunnelwithsufficientsoiltofmalayertakingsoilfromdifferentareasofthesampleinthepan.L

24、iftthefunnelby15mm(0.60in.)approximatelytheunconsolidatedlayerthicknesstobefmedspreadthesoilwithaslowspiralmotionwkingfromtheperimeterofthedevicetowardthecentersothataunifmlayerisfmed.Remixthesoilinthepanfeachsuccessivel

25、ayertoreducesegregationcausedbytakingsoilfromthepan.6.4.2Fsoilswithamaximumsizegreaterthan9.5mm(3?8in.)spreadthesoilfromascoop.Unifmspreadingcanbeobtainedbyslidingascoopfulofsoilinanearlyhizontalpositiondownalongtheinsid

26、esurfaceofthedevicetothebottomtothefmedlayerthentiltingthescoopdrawingittowardthecenterwithasingleslowmotionthisallowsthesoiltorunsmoothlyfromthescoopinawindrowwithoutsegregation.Turnthepermeabilitycylindersufficientlyft

27、henextscoopfulthusprogressingaroundtheinsideperimetertofmaunifmcompactedlayerofathicknessequaltothemaximumparticlesize.6.5Compactsuccessivelayersofsoiltothedesiredrelativedensitybyappropriateproceduresasfollowstoaheighto

28、fabout2cm(0.8in.)abovetheuppermanometeroutlet.6.5.1MinimumDensity(0%RelativeDensity)—Continueplacinglayersofsoilinsuccessionbyoneoftheproceduresdescribedin6.4.16.4.2untilthedeviceisfilledtotheproperlevel.6.5.2MaximumDens

29、ity(100%RelativeDensity):6.5.2.1CompactionbyVibratingTamper—Compacteachlayerofsoilthoughlywiththevibratingtamperdistributingthelighttampingactionunifmlyoverthesurfaceofthelayerinaregularpattern.Thepressureofcontactthelen

30、gthoftimeofthevibratingactionateachspotshouldnotcausesoiltoescapefrombeneaththeedgesofthetampingfootthustendingtoloosenthelayer.Makeasufficientnumberofcoveragestoproducemaximumdensityasevidencedbypracticallynovisiblemoti

31、onofsurfaceparticlesadjacenttotheedgesofthetampingfoot.6.5.2.2CompactionbySlidingWeightTamper—Compacteachlayerofsoilthoughlybytampingblowsunifmlydistributedoverthesurfaceofthelayer.Adjusttheheightofgivesufficientcoverage