Study on the influence of goaf filling on surface deformation in loess gully area

In order to study the influence of different filling schemes on overlying rock and surface deformation under the influence of topographic conditions, according to the mining and geological conditions of Luzigou Coal Mine, many kinds of numerical models of filling schemes considering topographic factors are simulated and analyzed by FLAC_3D software, and the deformation and failure characteristics of goaf roof and surface under different filling rates and filling positions are analyzed, and the stable effects of different filling schemes on goaf are obtained. The results show that the surface displacement decreases with the increase of filling rate; when the filling rate is between 20% and 70%, the filling effect increases obviously with the increase of filling rate, and there is an approximate linear negative correlation between the maximum total displacement and the filling rate; when the filling rate is less than 20% or more than 70%, the change of filling rate has little effect on the filling effect; interval filling can change the shape of surface subsidence basin; when the filling volume is kept at a certain amount, the surface settlement of interval filling scheme is smaller and the filling effect is better. The horizontal displacement of the surface slope affected by the goaf under the filling valley is smaller than that under the filling peak, and the possibility of slope instability is less.