Influence of material heterogeneity on the blast-induced crack initiation and propagation in brittle rock

Abstract

In the paper, we propose a peridynamic model for brittle rock with heterogeneous micro-modulus and heterogeneous critical stretch to investigate the influence of material heterogeneity on the blast-induced crack initiation and propagation. The discretization in polar coordinates is introduced into the proposed model to avoid the fallacious directional guidance to the crack initiation around the hole. The results show that the locations and sequence of the blast-induced crack initiation are determined by the material heterogeneity. The multiple cracks initiate and propagate with a tendency to bisect the circumference. The blasting loads just make the cracks initiate in the given sequence by the material heterogeneity. For the blast-induced crack propagation, the results demonstrate that the crack propagation speed is an essential index to reflect the blast-induced crack behavior, and cracks are more likely to propagate in rock with stronger material heterogeneity. We also explore the effects of blasting load parameters on the crack propagation. The decay rate of the blasting loads just affects the crack propagation while the load peak affects both the crack initiation and propagation. The results can offer a useful reference for the optimization of the blasting loads and outcomes.