Strata Behaviors of Recovering Room Mining Residual Pillars with Loess Filling

Taking the recovering room mining residual pillars with loess filling in a mine of Shenmu County as the engineering background, the stress on the pillars in front of working face, stress in the filling body behind working face and the surface subsidence during the filling operation are studied through using numerical simulation software of UDEC. As the results showed, along with the excavation filling operation, abutment pressure on pillars in front of working face increases gradually, and the scope in advance is about three pillars. The stress variation law in the filling body presents that "initial stress zone-stress increasing zone-stress basic stability zone". The maximum surface subsidence after recovering room mining residual pillars with loess filling is 338 mm and the control effect to surface is remarkable.