Abstract: Based on the geological conditions of Yuejin Coal Mine 25110 working face,the optimization model of pressure relief depth of large diameter boreholes is established by using FLAC2D numerical simulation software.Combining with the theory of energy propagation attenuation,the expression of impact risk index after pressure relief of boreholes is obtained.The pressure relief effect of large diameter pressure relief boreholes with different depths is analyzed and compared under certain parameters.The simulation results show that when the depth of large diameter pressure relief hole in 110 working face is 45 m,the impact risk index is the smallest and the pressure relief effect is the most obvious.

Key words: Rock burst, Large diameter borehole, Numerical simulation, Borehole optimization, Pressure relief effect