A micromechanics-based model for rocks exhibiting microcrack-induced damage in plastic solid matrix
Y. Shi, Wanqing Shen, J.F. Shao
Abstract
This work is devoted to modeling plastic deformation and microcrack-induced damage in quasi-brittle rocks under compression-dominating stresses. At the microscopic scale, a set of randomly distributed microcracks are embedded in an isotropic elastic–plastic solid matrix. The plastic deformation, microcrack propagation and frictional sliding are inherently coupled. By combining a rigorous homogenization procedure and thermodynamics framework, the frictional sliding along microcracks is described by a specific Coulomb-type criterion but as a function of the local stress field. The microcrack growth is driven by the conjugate thermodynamic force, which is directly related to the frictional sliding. The plastic deformation of solid matrix is described by a simple pressure dependent linear yield criterion and an associate flow rule, but affected by the microcrack-induced damage. A robust and efficient iterative algorithm is then proposed for numerical implementation of the coupled plastic–damage–friction model. This one is applied to studying mechanical responses of three typical rocks. Compared with experimental data, the efficiency of the proposed model is evaluated and its advantages with respect to previous models are outlined.