Study on water-blocking effect of main roof bearing structure in sharp dipping seam mining

This paper makes research on the water-blocking effect of bearing structure in main roof on the theoretical basis of equilibrium structure formation along the dip direction of steeply dipping coal seam. By establishing the relation between the force of bearing structure in main roof and pore pressure in WangJiaShan coal seam, it is concluded that the bearing structure of main roof begins to prevent from water raining when mining depth is more than 238.52 m. It is also concluded that the seepage flow begins to decrease in working face when the mining depth is more than 235 m by analyzing the relations between the seepage flow in working face and mining depth. The monitoring result on site is consistent with the theoretical calculation results. It is shown by numerical simulation results that the rainwater seepage disappears in some areas while the mining depth is more than 200 m, which can explain the water-blocking mechanism of the bearing structure of main roof. It is helpful for preventing the infiltration of rain water.