Overlying strata movement and stress evolution laws triggered by fault structures in backfilling longwall face with deep depth

Abstract

Many dynamic disasters such as coal wall caving and roof falling have happened during longwall face crossing fault. Combined with the coal seam geological conditions in the 1302 longwall face AB coal mine, the paper comprehensively studies the overlying strata movement and the stress evolution laws of stope during superhigh-water material (SHWM) backfilling longwall face across fault by UDEC numerical simulation, theoretical analysis and on-site measurement. The results show that the stress during stable state is affected by the fault will increases abnormally. While the longwall face pass through the fault, the stress will abated and the vertical displacement of the overlying strata of two sides of the fault is significantly different. The fault significant blocks the propagation of stress and development of plastic zone. The superhigh-water material filling mining management roof has good protection effect on the roof when the longwall face encounters fault, which can effectively weaken the blocks effect of fault on stress propagation and plastic zone development. The numerical simulation results are consistent with the field experiments, and the research result provides theoretical basis and technical guidance for safe and efficient production during superhigh-water material backfilling longwall face through the fault.