Ground Pressure Laws and Key Supporting Technology of Roof Cutting and Pressure Relief Without Roadside Filling Along Gob

In order to study the mine pressure laws and key supporting technology of roof cutting and pressure relief without roadside filling along gob, we carry out the theoretical analysis for mine pressure behavior laws of roof cutting and pressure relief along gob. Based on the engineering practice in Hengyuan Coal Mine II 632 tunnel, we continuously observed roadway deformation and working resistance of constant resistance anchor cable by arranging displacement observation points and roof constant resistance anchor cable dynamometer, and obtained the variation of roadway deformation, deformation rate and constant resistance of cable force during roadway retaining. The results showed that: the surrounding rock of retained roadway is intense after roof cutting, due to the impact load of roof sinking rapidly generated by the surrounding rock deformation, especially the strong floor heave; the surrounding rock deformation affected by dynamic pressure is more severe deformation; the average stress of constant resistance anchor cable of roof cutting and pressure relief along gob is 259.721 kN and the maximum force reaches to 275.76 kN, and the force of constant resistance anchor cable tends to be stable when the working face passes the measuring point; the key support technology without roadside filling roof cutting and pressure relief along goaf by “strengthening constant resistance anchor cable with anchor bolt (cable) support” in order to increase the strength of roof support, and “properly strengthen the support of floor when the floor is soft” and “pay attention to the strengthening support of roadway retention stage” is proposed.