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1、附录1外文翻译原文3.2Elasticmodels3.2.1AnisotropyAnisotropicmaterialhasthesamepropertiesinalldirections—wecannotdis-tinguishanyonedirectionfromanyother.Samplestakenoutofthegroundwithanyorientationwouldbehaveidentically.However,weknowthatsoilshavebeendepositedinsomeway—forexample,
2、sedimentarysoilswillknowabouttheverticaldirectionofgravitationaldeposition.Theremayinadditionbeseasonalvariationsintherateofdepositionsothatthesoilcontainsmoreorlessmarkedlayersofslightlydifferentgrainsizeand/orplasticity.Thescaleoflayeringmaybesuffcientlysmallthatwedono
3、twishtotrytodistinguishseparatematerials,butthelayeringtogetherwiththedirectionaldepositionmayneverthelessbesuffcienttomodifytheproperiesofthesoilindifferentdirections—inotherwordstocauseittobeanisotropic.Wecanwritethestiffnessrelationshipbetweenelasticstrainincrementand
4、stressincrementcompactlyaswhereisthestiffnessmatrixandhenceisthecompliancematrix.Foracompletelygeneralanisotropicelasticmaterialwhereeachlettera,b,...is,inprinciple,anindependentelasticpropertyandthenecessarysymmetryofthesti?nessmatrixfortheelasticmaterialhasreducedthema
5、ximumnumberofindependentpropertiesto21.Assoonastherearematerialsymmetriesthenthenumberofindependentelasticpropertiesfalls(Crampin,1981).Forexample,formonoclinicsymmetry(zsymmetryplane)thecompliancematrixhastheform:andhasthirteenelasticconstants.Orthorhombicsymmetry(disti
6、nctx,yandzsymmetryplanes)givesnineconstants:whereascubicsymmetry(identicalx,yandzsymmetryplanes,togetherwithplanesjoiningoppositesidesofacube)givesonlythreeconstants:Figure3.9:Independentmodesofshearingforcross-anisotropicmaterialIfweaddthefurtherrequirementthatandsetand
7、，thenwerecovertheisotropicelasticcompliancematrixof(3.1).Thoughitisobviouslyconvenientifgeotechnicalmaterialshavecertainfabricsymmetrieswhichconferareductioninthenumberofindependentelasticproperties,ithastobeexpectedthatingeneralmaterialswhichhavebeenpushedaroundbytecton
8、icforces,byice,orbymanwillnotpossessanyofthesesymmetriesand,insofarastheyhaveadomainofelasticresponse,w
