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1、11thCongressoftheInternationalSocietyforRockMechanics–RibeiroeSousa,Olalla&Grossmann(eds)©2007Taylor&FrancisGroup,London,ISBN978-0-415-45084-3EvaluationofBraziliantensilestrengthintransverselyisotropicsandstoneA.Tavallali,B.Debecker&A.VervoortDepartmentofCivilEngineering,Katholie
2、keUniversiteitLeuven,Leuven,BelgiumABSTRACT:ResultsarepresentedofanexperimentalstudyoffailurepatternsintransverselyisotropicsandstonesamplesinducedbytheBraziliantensiletest.Thevariationofthestrengthandthefailurepatternisexaminedasafunctionoftheinclinationanglebetweentheisotropicp
3、laneandtheloadingdirection.Foreachsample,thelengthoffracturesparalleltothe(isotropic)layers,aswellascorrespondingtootherdirectionsaredetermined.Forthetransverselyisotropicsandstoneinthisstudy,thetransitionanglerange(45◦–60◦)isdeterminedwherebytherelativeimportanceofbothtypesoffra
4、cturesswitches(i.e.paralleltoisotropiclayersandothers).1INTRODUCTIONIngeneral,rockmaterialneartheearth’ssurfacehasmechani-calpropertiesthatcanchangeasafunctionofthedirection,orinotherwordsareanisotropic.Moreandmorethisanisotropyistakenintoaccountwhentestingtherockmaterial,asinput
5、forthedesignandfornumericalmodelling.Hence,theknowl-edgeoftheanisotropicpropertiesisrequiredinstudiesofcivil,miningandpetroleumengineeringwithapplicationslikee.g.Figure1.DiscshapesampleandconfigurationoflayersinBrazilianstabilityofundergroundexcavations,slopestability,boreholetes
6、ts.θvariesbetween0◦and90◦.deformationandbreakageofrockbymechanicaltoolsandexplosives.Despiteitsimportance,rockanisotropyisoftenpoorlyunderstood.TheplaneoftransverseisotropyisassumedtobeparalleltoInthisstudy,onespecificformofanisotropyisconsidered,theapparentdirectionofrocklayerin
7、g.namelytransversalisotropy.Thetestsareconductedonstrat-Therockwascoredinthelaboratorybyusinga50mmifiedsandstoneandtheBraziliantensilemethod(diametricaldiameterdrillbit.Thedirectionofcoringwasparalleltotheloadingofcylindricaldiscs)isapplied.layering.Forthetest,athickness-to-diame
8、terratio(t/D)of0.5Althoughinsiturockismo