Three-dimensional Simulation of Dynamic Evolution of Mining-induced Overburden Fractures

Based on the discrete element method of discontinuous media, the whole process analysis of overlying stratum migration and fracture evolution in coal mining process of 3213 face of Xinjing Mine is carried out by using 3D numerical simulation software. The results show that the shape and size of fractured enrichment area of overburden rock will change with the advancing of working face. At the initial stage of working face advancing, it takes on the shape of “arch”. When working face advances to 80 m, it takes on the shape of “hollow circular arch” due to the gradual compaction of the central fissure in the goaf, and becomes “circular ring” after the mining is completed, and there are some differences in the size of the fracture enrichment zones at different positions in the “circle”. The morphology of the fracture enrichment area at both ends of the goaf tendency is approximately the same, and along the mining direction, the width and height of the fissure enrichment area above the working face is slightly larger than the open-off cut.