Implicit Time Integration of Elasto-Viscoplastic Multlaminate Model for Jointed Rocks

In this paper, the implicit time integration algorithm of elasto-viscoplastic analysis by FEM is proposed for multllaminate model of jointed rocks. For joint sets, non-tension and Mohr-Coulomb criteria are used as yield criteria, and detailed expressions are derived for yield function derivative vector (?) and the viscoplastic strain rate derivative matrixH, The method of calculating the time integration step length for multilaminate model of jointed rock is also proposed. Finally, the use of the algorithm is illustrated by the solution of an example.