Numerical Research on Fractured Surrounding Rock Deformation and Failure Law Caused by Submarine Mining

Abstract

The existence of cracks has a considerable influence on the deformation failure characteristics and mechanical behavior of the surrounding rock mass. For submarine mining in particular, if a fractured zone in which water is flowing is formed between the goaf and the overlying strata, it will result in a devastating disaster in the mine. Therefore, it is of great significance to understand the deformation and failure law of fractured surrounding rock. Based on field investigation and the self-developed Y-Mat finite-discrete element numerical calculation program, submarine mining in the Xinli mine under three different working conditions was simulated. The research results showed that when mining in fractured rock mass, the influence range was large, the surrounding rock deformation was significant, and a discontinuous stress field was generated. Backfill mining can effectively restrain the deformation failure of surrounding rock and reduce the occurrence of penetrating fractures. Moreover, the effect of backfill mining was more obvious in the fractured surrounding rock. The fault had a barrier effect on the penetration of surrounding rock cracks, but its effect was weakened in the fractured surrounding rock. Under the working conditions of the study area, i.e., backfill mining in the fractured rock mass, the primary fractures in the surrounding rock were destroyed first, followed by the intact rock mass between the cracks. It was possible for the fractures to run through the overlying strata. Double subsidence centers developed on the surface and the reflection of deformation on the surface showed obvious hysteresis. These research results can provide a reference for mining stability evaluation and disaster prevention in the study area.