Numerical simulation analysis of gangue-type filling design and filling effect in triangular coal area: take Zaoquan Coal Mine as an example

Coal mining usually remains a certain amount of triangular coal and other marginal coal bodies, and its safe and efficient mining has always been a key technical problem of triangular coal recovery. In this paper, the triangular coal recovery of Zaoquan Coal Mine 11 mining area in one division is taken as the engineering background, and the design method of gangue-type filling is proposed. Based on the limit balance theory, the method determines the reasonable width of the coal pillar as 6 m, and designs the alternate roadway digging and filling mode, realizing the parallel operation of roadway digging and filling. Numerical simulation is used to compare and analyze the filling effect of “alternating” excavation and “sequential” excavation. The results show that: under the “alternate” excavation mode, the filling body and coal pillar form a joint bearing structure, the stress in the middle of the coal pillar is reduced by 5% compared with that without filling, the roof settlement is reduced by 75%, and the displacement control efficiency in the deep high stress area reaches more than 70%. The stress distribution of “alternating” excavation mode is more balanced, and the deformation control effect of surrounding rock is significantly better than that of “sequential” excavation. This technology realizes the resource utilization of gangue underground, replacing 71 700 tons of marginal coal and dealing with 57 900 tons of gangue, which provides theoretical and technical references for the safe and efficient mining of the triangle coal area and the construction of green mines.