| Based on the field investigation of geological conditions and similar roadway support conditions of 13501 working face in Zhujixi coal mine,the physical and mechanical tests of coal and rock mass are carried out,and the influence of lower protective seam mining on surrounding rock stability of overlying coal seam roadway is analyzed in detail by theoretical analysis and numerical simulation,The surrounding rock stability of different sections of 13501 working face's track trough affected by the mining of lower protective layer is obtained.On the basis of mastering the cooperative relationship of bolt and cable,the supporting technical scheme of different sections of13501 working face's track trough is put forward.The main conclusions are as follows:(1)?the height of caving zone is about 3.3m,and the height of fault zone is about26.44 ± The 13-1 # coal seam of the protected layer is located in the bending subsidence zone caused by the mining of 11-2 # coal seam,and the coal seam structure has not been damaged.?The prediction results of mining subsidence show that the subsidence of 13-1#coal is about 1071 mm due to the mining of protective layer under11-2#coal.?The track channel of 13501 working face is located above the goaf of11501 working face.Although the mining of 11502 working face will not cause large subsidence of the track channel of 13501 working face,the mining of adjacent working face of 11501 working face still has a strong mining impact on the track channel of13501 working face due to the extremely insufficient mining of the lower protective layer.(2)The numerical simulation results show that:?after the mining of working face 11501,the maximum stress value of track along the track of 13501 working face on the coal pillar of the stoping line of 11501 working face is about 45.8mpa,and the vertical stress of the roadway in the goaf is about 18 Mpa.?The lateral support pressure is formed in the mining of 11502 working face.The vertical stress of the roadway in 13501 working face increases from 17.6mpa to 19.3mpa,and the influence range of the ahead mining is about 80 m.(3)The coal seam in the position where the track along the groove of the upper 13501 working face is sunk due to the mining of working face 11501,with the subsidence of about 1.31 M.The mining of working face11502 will have a secondary mining effect on the track running of working face 13501,and the subsidence will reach 1.43 M.(3)According to the space-time relationship and influence degree of mining in11501 and 11502 working faces on the track chute of 13501 working face,the track chute of 13501 working face is divided into four types.The first type is the track chute section of 13501 working face which is located on the outer coal pillar of stoping line of 11501 working face.After mining in 11502 working face,it will be affected by superimposed abutment pressure;The second type is the roadway affected by excavation first and then by mining in 11502 working face;The third type is the roadway affected by both driving and mining in 11502 working face;The fourth type is the roadway which is affected by the mining of 11502 working face.The simulation results show that the stability degree of surrounding rock of four kinds of roadways from high to low is the fourth kind of roadways > the second kind of roadways > the first kind of roadways > the third kind of roadways.(4)The field industrial test results show that the support of track chute in 13501 working face can meet the needs of mine safety production by using classified support technology,which provides reference for roadway support under similar conditions in Zhujixi coal mine.This paper has 74 pictures,9 tables and 76 references. |
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