Simulation of Dynamic Fracturing of Continuum Rock in Open Pit Mining

Abstract

To investigate the dynamic fracture mechanism related to blast-induced borehole breakdown and crack propagation, 2D distinct element commercial code was used. The dynamic stresses, material status and velocity vectors are plotted and shown to evaluate rock mass failure under blast load. This paper focuses on the propagation and dynamic effects of blast waves in continuum rock masses. In order to investigate the effect of high strain rate loading on rock mass failure, a numerical simulation was conducted. The 2D distinct element code was used to model blast load effect on rock failure and stress distribution through the rock mass due to blast wave propagation. The blast loading history was simplified and applied to the blasthole walls. Accordingly, the interaction of explosive energy transferred to the rock mass from the blasthole pressure was examined as a function of time. A Mohr-Coulomb material model was used for host rock to allow for plastic failure calculations. The conducted numerical study describes the role of dynamic stresses in blasting in a qualitative manner. On the other hand, a free face boundary was considered as a common blast operation which is conducted in surface mining.