The numerical simulation of the mining subsidence in different mining methods

The surface deformation and the variation of overburden stress field in different mining methods are analyzed by FLAC^3D in order to contrast the control effect of surface and overlying strata deformation between filling mining and strip mining,which are based on the filling material prepared in the lab and the theoretical strip mining scheme.The results show that a little of overburden elastic strain energy is released in the filling mining,which stress is smaller than the in-situ rock stress and the stress field varies with an almost linear fashion.There exist high-stress area in the overlying strata and stress concentration in the coal pillar of strip mining,so the stability of surrounding rock is less than the filling mining.The surface subsidence in the two mining methods is far less than the caving mining and the values of surface deformation are less than the allowable values of the buildings grade I in strip mining.Though the value of surface curvature is 0.02mm/m² bigger than the allowable value in filling mining,it can insure the safety of ground buildings.So the control effects of surface and overburden deformation are the best in the filling mining.