Study on rational parameters of pressure relief and rock burst prevention borehole layout in the extraction roadways of Qianqiu Coal Mine

Feng Yongle; Fang Jianchang; Zhai Xinxian; Zhang Zhen; Zhang Zhiyong

doi:10.16186/j.cnki.1673-9787.2025080026

Abstract：Objectives With the increase in coal seam mining depth and intensity,high-energy mine tremors frequently occur during the excavation of rockburst-prone coal mine roadways.Therefore,it is necessary to study the layout parameters of pressure relief boreholes on both sides of rockburst-prone roadways and their effectiveness in pressure relief and rockburst prevention.Methods Using the excavation of a mining road-way in the pillar area of the 16082 bottom-slice fully mechanized caving face in Qianqiu Coal Mine as the engineering background,an orthogonal experimental design was employed to establish various pressure re-lief borehole layout schemes with different depths,diameters,and spacings.The stress fields of the sur-rounding rock for each pressure relief scheme were numerically calculated to quantitatively study the pres-sure relief and rockburst prevention effectiveness,and the results were validated through field industrial tri-als.Results The results show that:(1)Using the transfer distance of the high-stress zone D as a quantita-tive evaluation index,when D≥1.42,the abutment pressure curve at the roadway sides transitions from a"single-peak"to a"double-peak"pattern,indicating sufficient pressure relief in the surrounding rock and a significant effect on pressure relief and rockburst prevention.(2)Range-variance analysis revealed that the influencing factors on the degree of high-stress zone transfer are,in order of significance:borehole depth,borehole diameter,and borehole spacing.Borehole depth primarily governs the transfer distance of the high-stress zone.The maximum transfer distance is positively correlated with borehole depth,while the average transfer distance is positively correlated with borehole diameter.When the borehole depth is constant,the average transfer distance shows a linear negative correlation with borehole spacing.Conclusions Field indus-trial trials demonstrated that after optimizing the pressure relief borehole parameters,the energy of mining tremors during roadway excavation was predominantly at 10² J,with fewer high-energy tremors of 10³ J and above.The convergence of the roof to floor and the average drilling cuttings volume from observation bore-holes decreased by 43%and 30%,respectively.Therefore,a quantitative threshold for the transfer dis-tance of the high-stress zone and an optimization system for pressure relief borehole parameters are pro-posed,providing theoretical guidance for efficient pressure relief in rockburst-prone roadways.