【英文标准名称】:StandardTestMethodforRockBoltLong-TermLoadRetentionTest
【原文标准名称】:岩石锚栓长期负载保持力试验方法
【标准号】:ASTMD4436-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D18.12
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:anchors(rock);fieldtesting;loadingtests;mines;pulltesting;rock;Pulltesting;Rockmaterials/properties/analysis;Anchorbolts;Fieldtesting--rock;Loadingtests--rock/relatedmaterials;Mines
【摘要】:Rockboltsareusedforsupportinavarietyofminingandcivilengineeringsituations.Afteraboltisinstalled,theloadgenerallydecreasesovertimeduetodeteriorationoftheboreholewall,creep,andotherfactors.Thisprocessmaybearrestedbyfullyencapsulatingtheboltshortlyafterinstallation.Thisisgenerallydonebypumpingtheboltholefullofcementgrout,thoughsyntheticresinsmayalsobeused.Therateofloadlossdeterminestheintervalduringwhichtheboltmustbeencapsulatedduringconstruction.Thelocalcharacteristicsoftherock,suchasroughnessoftheboreholeandinducedfractures,aresignificantfactorsintheloadlosscharacteristicsofthebolt.Toobtainrealisticvalues,thetestholesshouldbedrilledusingthesamemethodsasthoseusedfortheconstructionboreholes.Inestablishingatestingprogram,thefollowingfactorsshouldbeconsidered:Loadretentiontestsshouldbeconductedinallrocktypeswhereconstructionboltswillbeinstalled.Iftherockisanisotropic,forexample,beddedorschistose,thetestsshouldbeconductedinthesameorientationsrelativetotheanisotropyastheconstructionboltswillbeinstalled.Ineachrocktype,ateachorientation,andforeachanchorsystem,asufficientnumberoftestsshouldbeconductedtodeterminetheaverageandminimumlong-termcapacitieswithinafixeduncertaintybandatthe95%confidencelevel.Theallowableuncertaintybanddependsontheprojectandinvolvessuchfactorsasrockquality,expectedprojectlifetime,andimportanceoftheareastobebolted.Theuncertaintybanddeterminationwillrequireconsiderableengineeringjudgment.Asaroughguideline,atleastsixlong-termtestsforasinglesetofvariableshavebeenfoundnecessarytosatisfythestatisticalrequirements.Thedesignloadandinstallationloadontherockboltsystemshouldbepredetermined.Theinstallationloadislessthantheanchorcapacity,asdeterminedbyMethodD4435.Thedesignloadislessthantheinstallationload;theamountdependsonrockpropertiesandtheminimumtimerequiredtoencapsulatethebolts.Alternatively,thismethodcanberunforapredeterminedtimeintervalbasedonconstructionrequirements,andarealisticdesignloadcanbedeterminedfromthedata.Note18212;Thequalityoftheresultproducedbythisstandardisdependentonthecompetenceofpersonnelperformingit,andthesuitabilityoftheequipmentandfacilitiesused.AgenciesthatmeetthecriteriaofPracticeD3740aregenerallyconsideredcapableofcompetentandobjectivetesting/sampling/inspection/etc.UsersofthisstandardarecautionedthatcompliancewithPracticeD3740doesnotinitselfassurereliableresults.Reliableresultsdependonmanyfactors;PracticeD3740providesameansofevaluatingsomeofthosefactors.1.1Theobjectiveofthistestmethodistodeterminethetimeoverwhichrockbolttensiondecreasesfromtheinstalledvaluetoadesignatedminimumvalue.1.2Thistestmethodisapplicabletoanyanchorsystemwhichisnotfullyencapsulatedimmediatelyuponinstallation,includingmechanical,cementgrout,resin(epoxy,polyester,andthelike)orothersimilarsystems.1.3Thevaluesstatedininch-poundunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesaremathematicalconversionstoSIunitsthatareprovidedforinformationonlyandarenotconsideredstandard.1.4AllobservedandcalculatedvaluesshallconformtotheguidelinesforsignificantdigitsandroundingestablishedinPracticeD6026.1.4.1Themethodusedtospecifyhowdataarecollected,calculated,orrecorde......
【中国标准分类号】:P13
【国际标准分类号】:93_020
【页数】:5P.;A4
【正文语种】:英语