3D Numerical Study on the Growth and Coalescence of Pre-existing Flaws in Rocklike Materials Subjected to Uniaxial Compression

A novel, meshless numerical method, called general particle dynamics (GPD), is proposed to simulate the initiation, propagation, and coalescence of three-dimensional (3D), pre-existing penetrating and embedded flaws as well as size effects and large deformations of rock materials. On the basis of the nonlinear unified strength criterion, an elastic-brittle-plastic damage model was developed to reflect the initiation, growth, and coalescence of the 3D flaws and the macrofailure of rocklike materials by tracing the propagation of the cracks. Then, growth paths of cracks were captured through the sequence of such damaged particles. In this paper, the GPD code is applied to simulate the macrofailure, large deformation, and size effects of the heterogeneous rocklike materials. The present numerical simulations focus on the effects of sample sizes, the nonoverlapping length and types of flaws on the failure, and the complete stress-strain curves of the rocklike materials. The initiation, propagation, and coalescence processes of the wing cracks, the antiwing cracks, the oblique secondary cracks, the out-of-plane shear cracks, and the quasi-coplanar shear crack in a rocklike sample subjected to uniaxial compression is numerically simulated using GPD3D. The numerical results indicate that the nonoverlapping lengths and types of flaws significantly influence the coalescence types. The numerical results are in good agreement with the experimental results. It is proven that the GPD3D can adequately simulate the failure processes, large deformation, and size effects of the rocklike materials.