ROCKBURST ANALYSIS BASED ON DAMAGE CRACK MODEL OF HYPOPLASTICITY

Hypoplastic constitutive model is developed on the basis of nonlinear tensorial functions and without resorting to concepts of elasto-plasticity theory such as yield surface, plastic potential, flow and hardening rules, and decomposition of deformation into elastic and plastic parts. In this paper, based on the hypoplastic model, damage energy release rate is firstly deduced. By virtue of fracture criterion, damage evolution equation is then determined to analyze the propagating of crack in surrounding rock. Throughout this study, it is made clear that the unstable propagation of cracks is caused by the interaction between cracks and that free surface and then thin layers of rock mass are formed as a result of coalescence of cracks. Finally, formation mechanism of rockburst is concluded and the regularity of rockburst is explained quantitatively.