担水沟煤矿特厚煤层开采底板导水破坏带深度实测研究OA

In order to study the influence of extra-thick coal seam mining on the failure depth of working face floor,through two observation drilling holes in the floor of No.9204 Face in Danshuigou Mine,the variation characteristics of apparent resistivity of floor rock mass during the mining process of working face were observed and analyzed by direct current electric method.Combined with the spatial position relationship between working face and measuring point,the failure depth of floor under the influence of mining was obtained,and it was compared with the calculated values of statistical formula and theoretical formula without considering the influence of coal thickness.The results showed that the measured floor failure depth of the working face was 17.3 m and 18.3 m;the maximum failure depth of the measured floor was less than the statistical formula value of 7.81％～12.90％,which was greater than the theoretical formula value of 24.81％.Discussing its mechanism,it was considered that the coal thickness factor had less influence on the failure depth of the floor than the factors such as the inclined length of the working face and the mining depth.In addition,there was a thick layer of water-resisting sandy mudstone 17 m below the floor of the working face,which was not easy to produce water conduction cracks and reduces the depth of water conduction damage of the floor.