Study on roof deformation mechanism and control technology of cross-fault roof cutting and pressure relief self-forming roadway

Aiming at the problem that roof deformation of cross fault roof cutting and pressure relief self-formed roadway is large and difficult to support, the mechanism of roof deformation of self-formed roadway in cross fault roof cutting and pressure-relieving roadway is studied based on the engineering background of the transport channeling of No. 11101 face in the eastern district of Qipanjing Coal Mine, and the effect of the support method of “roof cutting and pressure relief + constant resistance anchor cable” on roof deformation control of self-formed roadway in cross-fault roof cutting and pressure relieving roadway is studied. A mechanical analysis model was established to study the influence of the relevant parameters of the roof on the direct roof stress of the roadway, and the deformation process of the roof of the roadway was divided into four stages. The calculation method of each stage and the total vertical displacement of the roof of the roadway were studied and the calculation formula was given, and the relevant parameters were substituted into the formula to solve the vertical displacement of the roof of the roadway across the fault. 3DEC numerical simulation software was used to establish the numerical calculation model of self-formed roadway with cross fault roof cutting and pressure relief, and the stress-strain evolution law of roadway roof near the fault and the control effect of constant resistance anchor cable were studied. The research results show that the error between the numerical simulation and theoretical analysis data of roadway roof deformation is 1.14% and 4.04%, respectively. The constant resistance anchor cable can effectively reduce the deformation of roadway roof. Compared with the non-constant resistance anchor cable model, the vertical displacement of roof on slit side of upper wall roadway is reduced to 16.8%, and the vertical displacement of roof on slit side of lower wall roadway is reduced to 50.7%. The roof of upper and lower wall roadway will have different degree of stress concentration in the process of mining through the measurement section of roadway, and the vertical stress concentration value of upper wall roadway roof is larger than that of lower wall roadway, which is 5.72 MPa and 4.48 MPa respectively. The constant resistance anchor cable can reduce the deformation rate of roadway roof near the fault, and control the deformation of roadway roof jointly with the gravel wall after the filling is completed. By comparing the displacement monitoring data of surrounding rock along the channel of No. 11101 face transport with the calculation results of the theoretical model, the error is less than 10%, which proves that the support method of “roof cutting and pressure relief + constant resistance anchor cable” has a good control effect on the roof deformation of cross fault roadway.