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1、附錄1外文翻譯原文3.2Elasticmodels3.2.1AnisotropyAnisotropicmaterialhasthesamepropertiesinalldirections—wecannotdis-tinguishanyonedirectionfromanyother.Samplestakenoutofthegroundwithanyorientationwouldbehaveidentically.However,weknowthatsoilshavebeendepositedinsomeway—forexample,sedimenta
2、rysoilswillknowabouttheverticaldirectionofgravitationaldeposition.Theremayinadditionbeseasonalvariationsintherateofdepositionsothatthesoilcontainsmoreorlessmarkedlayersofslightlydifferentgrainsizeand/orplasticity.Thescaleoflayeringmaybesuffcientlysmallthatwedonotwishtotrytodistin
3、guishseparatematerials,butthelayeringtogetherwiththedirectionaldepositionmayneverthelessbesuffcienttomodifytheproperiesofthesoilindifferentdirections—inotherwordstocauseittobeanisotropic.Wecanwritethestiffnessrelationshipbetweenelasticstrainincrementandstressincrementcompactlyasw
4、hereisthestiffnessmatrixandhenceisthecompliancematrix.Foracompletelygeneralanisotropicelasticmaterialwhereeachlettera,b,...is,inprinciple,anindependentelasticpropertyandthenecessarysymmetryofthesti?nessmatrixfortheelasticmaterialhasreducedthemaximumnumberofindependentpropertiesto
5、21.Assoonastherearematerialsymmetriesthenthenumberofindependentelasticpropertiesfalls(Crampin,1981).Forexample,formonoclinicsymmetry(zsymmetryplane)thecompliancematrixhastheform:andhasthirteenelasticconstants.Orthorhombicsymmetry(distinctx,yandzsymmetryplanes)givesnineconstants:w
6、hereascubicsymmetry(identicalx,yandzsymmetryplanes,togetherwithplanesjoiningoppositesidesofacube)givesonlythreeconstants:Figure3.9:Independentmodesofshearingforcross-anisotropicmaterialIfweaddthefurtherrequirementthatandsetand，thenwerecovertheisotropicelasticcompliancematrixof(3.
7、1).Thoughitisobviouslyconvenientifgeotechnicalmaterialshavecertainfabricsymmetrieswhichconferareductioninthenumberofindependentelasticproperties,ithastobeexpectedthatingeneralmaterialswhichhavebeenpushedaroundbytectonicforces,byice,orbymanwillnotpossessanyofthesesymmetriesand,ins
8、ofarastheyhaveadomainofelasticresponse,w
