Digital Simulation of Strata Control by Solid Waste Paste-Like Body for Backfilling

In order to determine the strength of the filling body and the safety of backfilling mining above the confined aquifer so as to predict the effect of the backfilling on strata movement,based on field geological conditions and the filling mechanism of the filling body,the distribution of subsidence area as well as the elastoplasticity area of roof and floor after the lower coal seam had been mined was researched by using the software FLAC.Different strength of filling bodies were used in the research for two situations that are 1) the overlying coal is mined,and 2) the overlying coal is not mined.The pressure in the working face and the stability of the roof is also analyzed in this paper.The results show that the paste filling mining can effectively control the strata movement and have a good effect to decrease the subsidence.The higher the strength of the filling body is,the better the effect of decreasing the subsidence is.However,if the strength is over 1 MPa,the subsidence will become slow.Therefore,considering both the safety and economy factors,the filling body with a strength of 1 MPa can ensure the safe mining.