Numerical Modeling On The Coalesence Of Blasting-Induced Cracking Zone Under Simultaneous Denotation Of Two Boreholes

It is a complicated process that rock damage and failure in blasting load. It has very important theoretical significance for studying the coalesence of blasting-induced damage zone when two boreholes are denoted simultaneously. Considering rock blasting and damage mechanism, the complex progress of rock blasting and damage is simulated by numerical model. The blasting zone development is analyzed when two boreholes are denoted simultaneously. Based on rock failure mechanism, the damage and failure mechanism is studied under explosive stress wave and blasting-induced gas pressure. A numerical model considering the rock heterogeneity is built to analyze rock fracture process at the mesoscopic levels. The rock blasting and damage is simulated on four cases of coupling charging, the effect of blasting stress wave velocity, hole spacing, geo-stress and cutting seam on the blasting damage is examined. The results are as follows:(1) Two stages which are named as dynamic failure under explosive stress wave and under quasi-static blasting-induced gas pressure are made for the rock blasting. The corresponding numerical simulation model is built. The whole process of rock blasting damage is simulated.(2) The blasting zone development and coalesence of blasting-induced damage zone under simultaneous denotation of two boreholes with different spacing is numerically studied. The borehole spacing of the damaged area is got. It is in agreed with that of the theoretical result.(3) The blasting damage development under different geo-stress is simulated. It is proved that the crack has priority to propagating in the direction with the higher geo-stress. The crack propagation and coalescence mechanism is analyzed under the different geo-stress.(4) The blasting damage development under different geometries of cutting seam cartridge is numerically simulated, the crack propagation in a controlled direction is reproduced. The related mechanism for the crack propagation controlled by the cutting seam cartridge is discussed.