A study of crack propagation during blasting under high in-situ stress conditions based on an improved CDEM method

Abstract

Considering the energy consumption of the crushed zone caused by blasting, the energy dissipation characteristics were investigated through theoretical calculation and a plug-in for calculation of energy reduction was made. As a result, an improved CDEM method suitable for studying blast-induced crack propagation was proposed. The improved CDEM method was then used to numerically simulate the blast-induced crack propagation under three different in-situ stress conditions: uniaxial in-situ stress, biaxial equal in-situ stresses and biaxial unequal in-situ stresses. It was found that the in-situ stress conditions had significant effects on the distribution of the blast-induced cracks, the evolution of blast-induced stresses and the propagation of the blast-induced cracks. At the uniaxial in-situ stress condition, the vertical in-situ stress reduced the tip stresses of the horizontal crack and inhibited the propagation of the horizontal crack. At the biaxial equal in-situ stress condition, the peak radial stresses and circumferential stresses of the gauging points decreased gradually with the increase of in-situ stresses. In particular, the circumferential stresses of the gauging points gradually changed from tension to compression with an increasing in-situ stress. At the biaxial unequal in-situ stress condition, there were different inhibitions on crack propagation in the horizontal direction and the vertical one.