Effective evaluation of pressure relief drilling layout for reducing rock bursts and sensitive factor analysis

Rock burst causes serious economic losses during mining. Due to the advantages of simple construction and strong adaptability to geological conditions, drilling pressure relief has been widely used in coal mine prevention and control of rock burst. To study the influence of drilling alignment angle on pressure relief effect, in this paper, according to the geological conditions of deep mining in a mine, the changes of parameters such as energy dissipation and strength reduction of different drilling specimens under single-axis compression were studied using the test method of coal-like material uniaxial compression synchronous acoustic emission test, and the crack propagation characteristics of drilling specimens are analysed. PFC2D calculation results were compared with laboratory tests. The results showed that the radial tension has an important influence on the direction of crack expansion; the number of boreholes remains unchanged. The arrangement of boreholes significantly affects the initiation and development of surrounding rock cracks and energy release. The pressure relief effect is the best when adjacent drilling holes are arranged at 120°, and the pressure relief effect is the worst when adjacent drilling holes are arranged in a straight line; the sensitivity order of influencing factors of drilling pressure relief is aperture > arrangement angle > horizontal distance between borehole centre.