A Simplified Failure Criterion for Intact Rocks

岩石破坏准则

RockMechRockEng

DOI10.1007/s00603-013-0408-5

ORIGINALPAPER

ASimpli edFailureCriterionforIntactRocksBasedonRockTypeandUniaxialCompressiveStrength

JiayiShen RafaelJimenez MuratKarakus

ChaoshuiXu

Received:9January2013/Accepted:25March2013ÓSpringer-VerlagWien2013

AbstractTheuniaxialcompressivestrength(UCS)ofintactrock,whichcanbeestimatedusingrelativelystraightforwardandcost-effectivetechniques,isoneofthemostpracticalrockpropertiesusedinrockengi-neering.Thus,constitutivelawstorepresentthestrengthandbehaviorof(intact)rockfrequentlyuseit,alongwithadditionalintrinsicrockproperties.Althoughtriaxialtestscanbeemployedtoobtainbest- tfailurecriterionparametersthatprovidebeststrengthpredictions,theyaremoreexpensiveandrequiretime-consumingprocedures;asaconsequence,theyareoftennotreadilyavailableatearlystagesofaproject.Basedontheanalysisofanextensivetriaxialtestdatabaseforintactrocks,wepro-poseasimpli edempiricalfailurecriterioninwhichrockstrengthatfailureisexpressedintermsofcon ningstressandUCS,withanewparameterwhichcanbedirectlyestimatedfromtheUCSforaspeci edrocktypeintheabsenceoftriaxialtestdata.Performanceoftheproposedfailurecriterionisthentestedforvalidationagainstexperimentaldataforeightrocktypes.Theresultsshowthatstrengthsofintactrockestimatedbytheproposedfailurecriterionareingoodagreementwithexperimentaltestdata,withsmalldiscrepanciesbetweenestimatedandmeasurementsstrengths.Therefore,the

J.ShenÁM.KarakusÁC.Xu

SchoolofCivil,EnvironmentalandMiningEngineering,TheUniversityofAdelaide,Adelaide,SA5005,AustraliaR.Jimenez(&)

E.T.S.I.Caminos,CanalesyPuertos,TechnicalUniversityofMadrid,28040Madrid,Spain

e-mail:rjimenez@caminos.upm.es;rafael.jimenez@upm.es

proposedcriterioncanbeusefulforpreliminary(triaxial)strengthestimationofintactrockswhentriaxialtestsdataarenotavailable.

KeywordsUniaxialcompressivestrengthÁIntactrockÁFailurecriterionÁRockstrength

1Introduction

Arockfailurecriterionrepresentsthestrengthofrockunderdifferentloadingconditions.Severalfailurecriteriahavebeenproposedduringthepastdecadesbymanyresearchers(seeHoekandBrown1997,1980;Sheorey1997;SinghandSingh2005;Singhetal.2011),andanewworkinggroupoftheInternationalSocietyofRockMechanics(ISRM)on‘‘SuggestedMethodsforFailureCriteria’’wasestablishedto‘‘tostandardizethedifferentfailurecriteriausedinpracticeandmaketheISRMmembersawareofnewdevelopments’’(HaimsonandBobet2012).Table1liststhefailurecriteriacoveredbytheworkinggroupandtheassociatedreferences.

Someofthesefailurecriteriautilizetheprincipalstresses(i.e.,theintermediateprincipalstress,r2,andtheminorprincipalstress,r3)to ndthemajorprinciplestress,r1atfailure.Severalfailurecriterianeglectthein uenceofr2andtheyarereferredtoas‘‘two-dimensional’’(2D)criteria;however,inmanycases,‘‘three-dimensional’’(3D)criteriathatincorporatethein uenceofr2couldbetterrepresentthebehaviourofrockinthe eld.However,3Dfailurecriteriaarenotyetsocommonlyemployedinpractice;apracticallimitationisthat‘‘theuseofatruetriaxialtestingapparatus’’isrequired,eventhough‘‘atthistimeonlyafewsuchdevicesareavailable’’(ChangandHaimson2012

).

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