Study on surrounding rock stress and control technology of goaf side roadway

S6-1 roadway in Changcun coal mine is a large deformation roadway with deep goaf side.A new scientific support method is urgently needed to improve the stability of the surrounding rock of the roadway.By analyzing the engineering geological conditions of the coal seam working face, four lithological samples from coal seam, roof and floor are determined for physical and mechanical tests.The test results are assigned to UDEC simulation software to simulate the coal pillar stress distribution and roadway deformation law at the project site.Based on the site conditions and simulation results, this paper designs different cut-top pressure relief schemes and compares them with numerical simulations.The simulation results show that when cutting the roof in the direction of the vertical roof, the cutting heights 26.1 m, 33.6 m, 44.0 m and 61.0 m correspond to the peak support stress of the coal pillars 28.5 MPa, 24.8 MPa, 23.1 MPa and 25.0 MPa, respectively; 10°, 20°, 30° and 40° correspond to peak support stresses of coal pillars of 24.26 MPa, 24.03 MPa, 23.26 MPa and 24.42 MPa, respectively.Based on the site geological conditions and construction conditions, the optimal plan is finally determined with a cutting roof height of 44.0 m and a cutting roof angle of 30°.The field test results show that the effect of the cut-top pressure relief combined with the supplement support scheme is significant, and the supporting coal pillar support stress and roadway deformation are effectively reduced.