Study on mining-induced fracture field of contiguous coal seam with BBM-DEM simulation

In order to-deeply understand the evolution law of mining-induced fracture field and the pressure-relief effect due to protective coal seam mining in contiguous coal seams,the BBM-DEM simulation method was used as the research method to exploit the fissures in the mining process of the No. 2 coal protective layer of Shaqu Coal Mine, and the modeling and preliminary numerical simulation analysis were carried out. The research results show that the contact surface of BBM tetrahedral block has a tensile failure mode after the mining of the protective layer, which truly reflects the movement law of the overlying strata during the process of advancing the working face. According to the failure mechanism of the contact surface, the distribution and development degree of the surrounding rock fracture are obtained;The displacement field of surrounding rock shows a trend of decreasing from bottom to top in vertical direction;The BBM block can more effectively show the process of rock fracture and dynamic instability under the pressure relief of protective layer and it is found that the vertical stress has a non-uniform distribution characteristic in the compaction area of the gob. The simulation method has the potential of refinement simulation, and its simulation results can deepen the understanding of the stress field and fracture field caused by coal seam mining, and provide a certain reference for field practice.