Numerical simulation of blasting-induced rock fractures

In the present study, the Johnson-Holmquist (J-H) material model is implemented into the commercial software LS-DYNA through user-subroutines to simulate the blasting-induced rock fractures. The J-H model consists of strength models for both intact and fully fractured materials, a polynomial equation of state, and a damage model that represents the material from an intact state to a fully fractured state. Influences of the key parameters in smooth blasting, viz., loading rate, distance from a free face, earth stress, and preexisting joint planes, etc., on fracture patterns are explored. According to the simulation results, the rock fracture pattern is significantly influenced by the loading rate. Fracture control techniques, namely, notched borehole and charge holder with slits are also simulated. Effectiveness of the fracture control techniques is demonstrated. The numerical simulation in the present study reproduces some of the well-known phenomena observed by other researchers. It has the potential to be applied in practical blast control and gas and hydraulic fracturing engineering. (C) 2007 Elsevier Ltd. All rights reserved.