Research On Law Of Surface Subsidence Of Fully Mechanized Caving Under Permafrost

The Jang Cang Niangmute mininge area is with a permafrost thickness of about 20?70m,which belongs to steep inclined coal seam.The particularity of permafrost determines the particularity of the law of surface subsidence after the coal seam mining in working face.Therefore,the study of the law of surface subsidence in the steep inclined coal seam under the permafrost has great significance.This paper takes the two mining area of Jang Cang Niangmute mine as the research object,then we adopts theoretical analysis,physical similarity simulation and numerical simulation to research the law of surface subsidence under the permafrost.Physical and mechanical parameters of permafrost is reached based on the data analysis and experiment results.Through physical similarity simulation experiment and numerical simulation,analyzed the characteristics of the subsidence.The results show that the subsidence curve of the surface deformation of the coal seam with large dip angle under permafrost is asymmetric,and the maximum subsidence point is inclined to the surface of the deep buried coal seam,the maximum subsidence is 2.14m.Separation is with lower strata,the maximum separation volume is 1.35m.With the increase of the thickness of permafrost,surface subsidence decreases gradually,range of it increases gradually.The maximum horizontal displacement decreases gradually,and the range of horizontal movement gradually increases.The first break of the permafrost deformation and subsidence value is 1.48m,and the first break distance is 291m.When the settlement deflection reaches 0.11m,the periodic breaking is broken,and the breaking distance is 85m by theoretical calculation.The research results are of great significance to the control of surface damage in coal seam mining under permafrost.