Prediction of Fragmentation Zone Induced by Blasting in Rock

Abstract

This paper presents a simple method to evaluate the two-dimensional fragmentation zone induced by gas pressure during blasting in rock. The fragmentation zone is characterized by analyzing crack propagation from the blasthole. To do this, a model of the blasthole with a number of radial cracks of equal length in an infinite elastic plane is considered. In this model, the crack propagation is simulated by using two conditions only, the crack propagation criterion and the mass conservation of the gas. As a result, the stress intensity factor of the crack decreases as crack propagates from the blasthole so that the crack length is determined. In addition, gas pressure inside blasthole also continues to decrease during crack propagation. To validate suggested analytical solution, discrete element method is used by comparing length of propagated crack due to blasting.