Particle-Based Numerical Manifold Method to Model Dynamic Fracture Process in Rock Blasting

A particle-based numerical manifold method (PNMM) is developed to investigate rock fracturing behavior under dynamic loading. The basic idea of PNMM is to represent the microstructure of rock with a group of particles and to simulate the macroscopic behavior of rock masses through polygonal elements, which is performed by a dual-level discretization system. The first discretization is in the manner of FEM, which reduces the infinite degrees of freedom (DOF) of a continuum to the finite DOF of polygonal elements. However, the DOF of the model are not further affected by the latter discretization. The behaviors of internal particles are obtained from the mechanical fields of their governing elements. A dual-layer-cover system, i.e., the mathematical cover and the physical cover, is adopted in PNMM. Fracture initiation and propagation at a macroscopic level are represented as the coalescence of microcracks induced at the microscale level between particles. The Johnson-Holmquist-Beissel (JHB) model is incorporated into PNMM to simulate a borehole blasting under dynamic loading conditions. Numerical simulations show a good agreement with experimental and numerical results in the literature. (C) 2016 American Society of Civil Engineers.