Feasibility Study On Successively Mining Of Upper And Lower Formation Working Face In Confined Water In Rongkang Coal Mine

The 11#coal facing the problem of confined water in floor and mining under the goaf.Based on the actual conditions of 11101 working face in Rongkang coal mine,the distribution law of rupture zone in floor is studied,and its feasibility is determined.The research results have important theoretical significance and practical value to the actual production of Rongkang coal mine.The physical and mechanical parameters of the rock at the top and bottom of the coal seam are obtained by ZK102 drilling and 87 drilling core and measured in the laboratory.Through the 3Dec numerical simulation analysis,the maximum failure depth of the 11101 working face is 20.3m under the condition of successively mining,and the damage area is mainly concentrated in the middle of the stope,and the damage is smaller around the stope.Through the 3Dec numerical simulation,we analyzed the failure of 11101 working face under the condition of non-repetitive mining.It was found that the maximum failure depth of the floor rock formation was 22.3m,and the failure range of the floor rock formation under non-repetitive mining conditions is significantly larger than that of the underlayers under successively mining conditions.The mechanical model of t stope floor under successively mining conditions is obtained through the existing mechanics model of the stope floor and the numerical simulation results combined with of 11101 working face under successively mining conditions.The floor plate is divided into the similar to the original rock stress area,pressure relief area,stress concentration area and the original rock stress area according to the different stress size in floor.Based on the result of theoretical calculation,numerical simulation and the comparison of adjacent mines,the maximum failure depth of 11101 working face is 22.43 m.The feasibility of the mining is determined by the correction of water inrush coefficient method,the rock-water stress relation method and the plasticity theory of the floor plate water barrier.The comprehensive judgment result is that the 11101 working face of Rongkang coal mine can not be taken in the absence of effective measures.