Research On The Entry Layout And Support Technology Under The Goaf And Variable Thickness Of Gangue

At present,most coal mines have entered deep mining,and the bifurcation phenomenon of thick coal seam is common.If the thickness of the gangue under the goaf is small,when the gangue is affected by the mining of the upper coal seam,the gangue in the coal seam and the lower coal seam will be damaged,which makes the support technology of the lower coal seam mining roadway more difficult,so the rational layout and support technology of the roadway is a new technical problem encountered in Nantun Coal Mine at present.The main research results obtained are as follows:(1)Firstly,the composition and microstructural characteristics of the gangue-trapped seam,the stress and failure characteristics of the floor in goaf,and the damage degree of the floor caused by the mining of three upper seams under different gangue-trapped thickness are studied and analyzed,and the mechanical properties of the gangue-trapped roof and coal seam under three seams are tested experimentally.(2)According to the deformation and failure characteristics of coal and rock in mining affected area,the supporting principle of roadway is determined by analyzing the roof load and stress of roadway with different gangue thickness.(3)Through the influence of concentrated abutment pressure of residual coal pillars in goaf of upper coal seam on roadway layout,the roadway layout which is beneficial to spontaneous combustion of floating coal in goaf of upper coal seam 3 and the roadway layout under thin gangue of gob according to roof lithology,the roadway layout under thin gangue of goaf is determined.(4)Combining with the actual situation of Nantun Coal Mine,The thickness of thin gangue is divided into three categories,and the supporting schemes of these three kinds of thickness are explored as follows:under the thickness of thin gangue,bolt-anchor-cable coupling support should be adopted for mining roadway under the thickness of 3m or less,bolt-net rigidization or bolt-cable truss support should be adopted for mining roadway under the thickness of 3-5m gangue,and bolt-anchor-cable coupling support should be adopted for mining roadway under the thickness of 5m gangue.