The interfacial coupling structure between the backfill and ore rock body in the filling mining method will be continuously disturbed by the influence of mining and blasting. In the filling-rock interfacial coupling, it is easy to produce the behaviors of debonding and fissure expansion, which will bring potential safety hazards to underground production. Because the field experiment is time-consuming and laborious, and it is difficult to observe the impact effect and the rock crack propagation process when the explosive is detonated, the simulation method was adopted for research. In the simulation, reasonable simplification is particularly important. According to the actual situation of blasting hole layout, the three rows of blasting holes that were detonated at one time were simplified into a single-row blasting hole model and an edge blasting hole model. According to the research results in related literatures, the coupling surfaces of the filling bodies and the ore rocks were simplified into three kinds (a flat interface, wavy interface and serrated interface). The three different shapes of the interfaces correspond to the different roughnesses of the interfaces, respectively. By considering that the hole arrangement method used in stope blasting is vertical hole arrangement, the holes are parallel, and at the same time, in order to improve the calculation of the software efficiency, simplified the three-dimensional model of the stope into a two-dimensional plane model. After a series of simplifications, a physical model for the filling-rock interface coupling body was proposed, and the corresponding geometric analysis model was established by using the ANSYS/LS-DYNA software And different material parameters were assigned to the different parts of the model, and the blasting effect was analyzed by software calculation. The mechanical influence of the interface coupling body structure was obtained, and the response law of different interface roughness, the curing age of the filling body and the blasting method on the blasting shock was obtained, and the mechanism of the blasting dynamics was discussed. The research results can reveal mechanical behaviors such as debonding and crack propagation at the coupling of filling-rock interface, and clarify the influence of different factors on the law of blasting shock response and the mechanism of blasting dynamics, which has certain guiding significance for downhole safety production. The results show as follows. (1) The blasting impact has three mechanical effects in the interface coupling body: tension, pressure and shear. When the stress wave passes through the interface, the peak acceleration of the monitoring point at the interface will increase due to different degrees of refraction. After passing through the coupling interface, the stress wave energy decays rapidly. (2) The impact of different interface roughness on blasting action is different. The joint roughness coefficient (JRC) represents the roughness of the interface coupling body. With the increase of the JRC value, the interface stress tends to rise first and then decline, but the overall damage decreases. (3) As the curing time of the backfill increases, the fracture range at the coupling interface shrinks, and the interface damage gradually changes from tensile damage to shear damage. (4) The damage of different detonation modes to the interface coupling body is different, and the damage of simultaneous detonation to the coupling interface is weaker than that of hole-by-hole detonation. © 2021, Editorial Staff of EXPLOSION AND SHOCK WAVES. All right reserved.
