A discontinuous sub-block meso-damage evolution model for rock mass

摘要

As an effective numerical simulation method, DDA is used in the stability evaluation of rook mass widely although it has some limitations. The failure of rock mass is due to crack propagation between rock maases and the failure within the rock. In the existing DDA methods, the first factor is taken into account usually. Some researchers consider the second factor using fracture mechanics. But remeshing makes the computation complex, and sometimes even difficult. In this paper, a discontinuous sub-block meso-damage evolution model is proposed. In the new model, each block is divided into smaller sub-blocks. There are two kinds of contacts between sub-blocks. One is continuous and the other is discontinuous. The continuity condition can change along the sub-block contacts and the continuous contacts can convert into discontinuous ones using Mohr-Coulomb criterion. The two kinds of contacts are modeled using the Augmented Lagrangian Method. The failure of rock mass is a progressive process. There is damage in rock mass before it loses stability. So the meso-damage mechanics is introduced into the new model. The tensile damage and shearing damage in the sub-block are considered.