Study On Roadway Layout And Surrounding Rock Control Of Large Buried Depth And Short Distance Lower Coal Seam

In view of the large deformation caused by high stress under the small horizontal spacing internal staggered arrangement of mining roadway in large buried depth and short distance lower coal seam,thesis takes the transportation roadway of ji16,17-31020 working face with 954 m buried depth and 8 ? 12 m distance from ji15 coal seam as the research object,and studies the stope support pressure distribution,floor mining damage characteristics,and According to the temporal and spatial evolution law of floor stress,the layout mode of large horizontal spacing out dislocation of roadway is proposed,and the roadway surrounding rock control technology of full section anchor mesh cable is defined.The main results are as follows:(1)By sampling the coal seam and roof and floor in the field study area and doing the indoor tension,compression and shear test,it is obtained that the uniaxial compressive strength of the roadway roof and floor are 4.21 MPa,8.23 MPa and 3.59 MPa respectively,which makes it clear that the coal seam,roof and floor are relatively soft;The deformation law of surrounding rock with rapid initial deformation and continuous deformation near the roadway with an internal dislocation of 10 m is measured,and the characteristics of large deformation of surrounding rock caused by the roadway under the residual pillar stress concentration area of the upper coal seam are clarified.(2)Combined with the distribution characteristics of stope abutment pressure,the theoretical model of floor mining damage and the calculation model of floor stress,the damage characteristics of floor after mining of upper coal seam are studied,and the boundary length of floor passive stress area is 10.6 M;The temporal and spatial evolution law of floor stress in different mining stages is clarified,and the characteristics that the peak value of floor stress under coal pillar decreases from63.38 MPa to 54.63 MPa,and then there is no obvious change are revealed.(3)Based on the factors such as the boundary length of the passive stress area of the floor,the friction coefficient between the coal seam and the roof and floor,the influence angle of coal pillar pressure,the mining efficiency of the working face and the recovery rate of coal resources calculated theoretically,the layout mode with a large horizontal distance of 25 m outside the roadway in the near lower coal seam is proposed,and the stress and displacement distribution characteristics of the roadway surrounding rock under this layout mode are studied.(4)Combined with the advantages and disadvantages of different support methods and the actual production conditions of the roadway,the full section high-strength anchor mesh cable support method is proposed.Using the numerical calculation software,the influence of the change of anchor cable row spacing parameters on the control effect is systematically analyzed.Finally,it is determined that the "roof row spacing is 1200" × 1600 mm ? twenty-two × The row spacing between 6500 mm prestressed anchor cable + top plate is 700 × 800 mm ?twenty-two × 2600 mm high-strength prestressed anchor bolt + row spacing between two sides is 750 × 800 mm ? twenty × Control scheme of "2400mm high strength prestressed anchor rod".(5)The selected support scheme is applied in the transportation roadway of16,17-31020 working face,and the construction technology and requirements are put forward.The industrial practice shows that the maximum displacement of the roadway roof and two sides under the support scheme are 70 mm and 100 mm respectively.It is verified that the layout of large horizontal distance external dislocation can effectively avoid pressure,the stress of roadway is small and the support effect is good,which can effectively solve the large deformation problem of large buried depth and short distance coal seam,and can provide reference for mines with similar conditions.here are 60 figures,8 tables and 93 references in thesis...