Numerical study on fracture control blasting using air–water coupling

Abstract

AbstractFracture control blasting produces rock fractures in the desired direction, which is significant for the stability of excavation structures in rock engineering. The present study proposes a new method of fracture control blasting using air–water coupling. This method utilizes the difference of explosion stress transfer between air and water, which guides the explosion energy consumption in fracturing rock on water-coupling side, i.e. rock in the excavation zone, and thus the rock in the excavation zone is properly fragmented, and the reserved rock is well protected from damage. Based on the plane strain assumption, the transmission and propagation of explosion stress in the excavation and reserved rock with this method are first theoretically analyzed. Then, fracture control blasting using air–water coupling is numerically studied utilizing the LS-DYNA program. The numerical model is first developed and calibrated in the simulation with the laboratory-scale air-coupling and water-coupling blasting tests. Then, the successive processes of pressure attenuation, fracture evolution and energy consumption under air–water coupling blasting are numerically investigated. Thereafter, the effects of the air–water ratio and decoupling ratio on the performance of fracture control are numerically investigated. The theoretical and numerical results show that good performance of fracture control can be obtained using air–water coupling blasting.