Floor failure and roadway deformation induced by contiguous coal seams mining at Huopu Mine

Mining-induced floor failure of contiguous coal seams, numbered 1#, 3#, 5#, 7#, and 12#, is studied by theoretical calculation and numerical simulation based on the geological conditions at Huopu Mine. The results indicate that pressure relief failure of the floor in the mining of contiguous coal seams is notably different from that in the mining of a single coal seam. During the mining of the current panel, a large range of surrounding rocks becomes unstable due to overlapping mining pressure induced by contiguous coal seams. This leads to strong dynamic disturbance and aggravates the damage of roadway surrounding rocks. The field measurement data of stone gate 231 suggest that its surrounding rocks are further damaged and destroyed under the dynamic disturbance caused by the instability of large overburden structures. This is consistent with the numerical simulation results. Therefore, effective supporting measures should be implemented for each loading and unloading cycle in order to maintain the stability of roadway surrounding rocks.