Numerical simulation on complete process of three-dimensional bench blasting in an open-pit mine based on CDEM

Abstract

Blasting mining is the most important part of the total cost control in an open pit mine, and numerical simulation is an effective method to optimize the design of blasting mining and to analyse blasting effect. By using the continuum-discontinuum element method (CDEM), the three-dimensional bench blasting process of the open pit mine is simulated. The Landau explosive model is adopted to precisely calculate the blasting effect, and the elastic-damage-fracture constitutive law is used to describe the damage and fracture process of rock. By adopting the semi-spring target face and semi-edge target edge combined contact algorithm, the collision, flying and accumulation process of large number of fragments is simulated efficiently. The numerical simulation of the small scale blasting process with the single free surface is carried out. The block distributing curve and volume of the crater obtained by numerical simulation are more or less the same as those obtained by experiment, which demonstrates that CDEM and corresponding models described in this paper are good at simulating the rock blasting process. Based on the blasting technology in the south region in Anqian open-pit mine, a generalized three-dimensional bench blasting model with 3 rows and 21 bore holes is set up, and the complete process from explosive detonation to muckpile formation is carried out. Numerical results show that, except the tensile crack behind the blasting area, the muckpile shape and heaving height obtained by numerical simulation are accordant with the ones obtained by field test to some extent, which demonstrates the feasibility to simulate the three-dimensional bench blasting by CDEM.