Research On The Influence Of Solid Filling Mining On Surface Deformation Under Different Terrain Conditions

The treatment of goaf is a difficult problem to be faced in coal mining.The research of goaf roof control technology is also the focus of mining technology research.Filling mining has become an important means to control roof strata movement and surface deformation.Filling mining can also replace the remaining coal pillar,liberate part of the "three under" coal resources,improve the coal mine production life and coal recovery rate,and reduce various secondary disasters caused by goaf deformation.Among them,the advantage of solid filling material with coal gangue as the main component is more and more obvious,which can not only meet the material performance requirements of filling mining,but also reduce or even eliminate the eco-environmental problems caused by the accumulation of waste gangue.Avoid landslides and other geological disasters caused by gangue instability,in line with the basic requirements of green mine construction in China.Considering the material source and filling cost of gangue filling,this paper makes a comparative study on a variety of filling schemes under different topographic conditions,and analyzes the characteristics of roof and surface deformation under the control of non-uniformly distributed load.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 FLAC3D 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:(1)Under the conditions of two kinds of topography,the effect of filling rate on filling effect is similar.With the increase of filling rate,the value of surface displacement decreases gradually,but there is a non-linear negative correlation between them.The change of the filling effect is not obvious when the filling rate is less than 20%;when the filling rate is between 20%and 70%,the filling effect increases obviously with the increase of the filling rate,and the maximum total displacement is approximately linearly negatively correlated with the filling rate;when the filling rate is greater than 70%,it has little effect on the filling effect by increasing the filling rate.(2)Interval filling can change the shape of surface subsidence basin.when the total filling volume is kept at a certain amount,the surface settlement of interval filling scheme is smaller and the filling effect is better than that of comprehensive filling scheme.(3)Under the condition of plain topography,the smaller the filling spacing is,the smaller the load on the single filling body and coal pillar is,the smaller the influence of the goaf on the surface is,and the better the filling effect is.Under the condition of valley topography,the horizontal displacement of the surface slope affected by the goaf is smaller and the slope is less likely to be unstable than the goaf under the filling peak.