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1、附录1外文翻译原文3.2Elasticmodels3.2.1AnisotropyAnisotropicmaterialhasthesamepropertiesinalldirections—wecannotdis-tinguishanyonedirectionfromanyother.Samplestakenoutofthegroundwithanyorientationwouldbehaveidentically.However,weknowthatsoilshavebeendepositedinsomeway—forexample,sedi
2、mentarysoilswillknowabouttheverticaldirectionofgravitationaldeposition.Theremayinadditionbeseasonalvariationsintherateofdepositionsothatthesoilcontainsmoreorlessmarkedlayersofslightlydifferentgrainsizeand/orplasticity.Thescaleoflayeringmaybesuffcientlysmallthatwedonotwishtot
3、rytodistinguishseparatematerials,butthelayeringtogetherwiththedirectionaldepositionmayneverthelessbesuffcienttomodifytheproperiesofthesoilindifferentdirections—inotherwordstocauseittobeanisotropic.Wecanwritethestiffnessrelationshipbetweenelasticstrainincrementandstressincrem
4、entcompactlyaswhereisthestiffnessmatrixandhenceisthecompliancematrix.Foracompletelygeneralanisotropicelasticmaterialwhereeachlettera,b,...is,inprinciple,anindependentelasticpropertyandthenecessarysymmetryofthesti?nessmatrixfortheelasticmaterialhasreducedthemaximumnumberofind
5、ependentpropertiesto21.Assoonastherearematerialsymmetriesthenthenumberofindependentelasticpropertiesfalls(Crampin,1981).Forexample,formonoclinicsymmetry(zsymmetryplane)thecompliancematrixhastheform:andhasthirteenelasticconstants.Orthorhombicsymmetry(distinctx,yandzsymmetrypl
6、anes)givesnineconstants:whereascubicsymmetry(identicalx,yandzsymmetryplanes,togetherwithplanesjoiningoppositesidesofacube)givesonlythreeconstants:Figure3.9:Independentmodesofshearingforcross-anisotropicmaterialIfweaddthefurtherrequirementthatandsetand，thenwerecovertheisotrop
7、icelasticcompliancematrixof(3.1).Thoughitisobviouslyconvenientifgeotechnicalmaterialshavecertainfabricsymmetrieswhichconferareductioninthenumberofindependentelasticproperties,ithastobeexpectedthatingeneralmaterialswhichhavebeenpushedaroundbytectonicforces,byice,orbymanwillno
8、tpossessanyofthesesymmetriesand,insofarastheyhaveadomainofelasticresponse,w
