Abstract Based on the results of cyclicloading tests of two kinds of marbles T6 2y and T2b from Jinping II hydropower station,the elastoplastic coupling,strain-hardening and softening,shear dilatancy characteristics of rock are studied. Then,an elastoplastic coupling mechanical model is proposed with taking the following aspects into consideration:(1) A plastic internal variable which takes the influence of confining pressure into consideration is defined. (2) The variation of elastic parameters with plastic strain is concerned. (3) Based on the Mohr-Coulomb yield criterion,the evolution law of strength parameters during the plastic deformation is put forward. (4) The applicability of the generalized normality rule is validated and the method to handle shear dilatancy is proposed. The elatoplastic coupling model is embedded through the fast Lagrangian analysis of continua in three- dimension(FLAC3D) and is simulated by the triaxial compression test. The results show that the constitutive model can reflect properly the main mechanical characteristics of rock. Then,the unloading confining pressure tests are also simulated and the deformation and strength characteristics of marble are well obtained. The research results provide important reference to the understanding and analysis of yield process of brittle rock.
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Received: 02 June 2010
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