Investigation on Mechanism of Coal Burst Induced by the Geological Weak Surface Slip in Coal Seam Bifurcation Area: A Case Study in Zhaolou Coal Mine, China

Abstract

Abstract The coal seam bifurcation area (CSBA) exists widely in coal measure strata, where the geological weak surface (GWS) slip in overburden structure is easy to induce coal burst. The coal mass of coal face shows overall instability failure and high-speed throwing characteristics during the coal burst, seriously threatening the safe and efficient coal mine production. In order to understand the GWS-induced coal burst caused by the slip in CSBA and find the main controlling factors of GWS slip, the GWS slip criterion in CSBA was established based on the coal burst case analysis of overburden structure in CSBA of 1305 coal face (1305CF) in Zhaolou Coal Mine. The case study showed that the angle and range of CSBA are the main controlling factors affecting GWS slip. The FLAC3D numerical model of CSBA was established to analyze the influence effect of main control factors. The results show that the increase of angle and range of CSBA will increase the influence scope and degree of coal face mining, improving coal face burst risk. However, the peak point region of abutment pressure will not be affected, gradually reaching its peak within 0 m ~10 m from the coal seam merging area. With the increase of the angle of CSBA, the integrity of the triangular wedged rock mass along the GWS slip will be enhanced, aggravating the dynamic disturbance to the coal mass. With the increase of the range of CSBA, the slip of triangular wedged rock mass along GWS gradually changes from integral slip to phased slip, which will intermittently disturb the coal mass of the coal face. The research results have certain theoretical significance and practical value for preventing and controlling coal bursts in CSBA.