Control Of Roof Cutting And Pressure Relief Surrounding Rock Of Gob-side Entry Retained In Lutaishan Mine

Taking the 2204 working face of Lutaishan Mine as the research background,this paper uses theoretical analysis,numerical simulation,engineering practice and other methods to explore the mechanism of the top pressure relief on the roadway along the empty roof under the hard roof,and draws the following conclusions:(1)Combining theoretical analysis and numerical simulation,the stress and crack development law of the filling body during roadway retention are revealed,and the necessity of hard roof topping pressure relief is put forward.On this basis,the roof pre-cracking and unloading is given.The technical idea of pressure.(2)Using UDEC software to simulate the stress variation of surrounding rock in the retaining roadway along the goaf,on the basis of this,the simulation experiment of the topping and unloading of the roadway along the goaf is carried out,and the stress and displacement after the roadway retaining along the goaf and the pressure of the top is relieved.The evolution law is carried out,and the stress and deformation before and after pressure relief are compared and analyzed.(3)After numerical simulation,the internal peak stress of the filling body is reduced from 22MPa-27 MPa to 14MPa-18 MPa.In-depth study of the influence of cutting parameters(cutting depth,cutting angle)on surrounding rock deformation and stress,the parameters are as follows: cutting depth(4m,8m,12 m,16m),through numerical simulation and on-site industrial test,It is concluded that the optimal solution for the cutting height of the 2204 working face is 12 m.The change of the cutting angle makes the wall stress develop in a wave shape,and the cutting angle is changed by numerical simulation(10°,15°,20°,30°,45°)It is concluded that the optimal solution of the 2204 working face cutting angle is 30°,which is consistent with industrial practice.(4)Design the roadway surrounding rock monitoring program,conduct on-site industrial test,and find out that the working surface of the roadway is about 80 m,the roadway has the fastest deformation rate and the highest instability,and in the overall change situation,two The amount of deformation that helps the top plate occupies a large proportion.