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

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.