According to the typical conditions of special water preserved mining area, the aquiclude stability with two equispaced filling strips is analyzed by using the physical simulation experiment and theoretical analysis, and the mechanical model of elastic foundation beam of strip filling aquiclude strata is set up. Based on that, the calculation method of load and the compression displacement of the filling strip is presented, and the deflection formula of the water resisting beam is given, and the position and depth of the downward crack is determined. Based on the aquiclude stability criterion, the calculation method of reasonable filling strip width and interval width is put forward. The result shows that the reasonable strip interval increases with the increase of the mining height, the thickness and strength of the beam, and the depth of the downward crack is mainly relate.
There are rich shallow buried coal seams in the Western China, and the coal reserves and production are among the forefront (Huang 2002). The water preserved mining is an urgent and frontier research project of shallow coal seam mining (Qian et al. 2003). Our study shows that the stability of aquifuge is related with the mining height and aquiclude thickness. Based on the study of dynamic fracture of overburden, the aquiclude stability criterion have setup, and the water preserved mining classification have put forward according to the geological conditions of Yushenfu coal field (Huang 2010, Wang et al. 2010). Among them, the overburden aquiclude thickness less than 18 times mining height is named special water preserved mining, and the aquiclude rock group will be completely in the water flowing fractured zone after roof caving mining. For this case, it needs to take filling mining method to realize water preserved mining.