Study on Rationality of Large Diameter Pressure Relief Drilling Parameters Under Different Coal Seam Conditions

To study the influence of changes in the coal seam mechanical characteristics at depth on the stress relief effect of a borehole, this paper established the relationships between the borehole spacing, elastic modulus, and Poisson’s ratio of the coal seam. It then analyzed the stress relief effect of different borehole spacings in different coal qualities in a deep coal seam, using the FLAC^3D numerical simulation software. The results indicated that after boreholes with different spacings were drilled in the deep coal seam, the peak stress value of the roadway-surrounding rock was transferred to the deep coal body, and the original peak stress position was reduced to varying degrees. Under the premise of ensuring the stress relief effect and improving stress relief efficiency, the relationship between borehole spacing and the elastic modulus of the coal seam was a negative exponential function, whereas the spacing of boreholes and Poisson’s ratio of the coal seam had a logarithmic function relationship. The research conclusions were applied to the − 1000 West No. 1 mining area in the Tangkou coal mine, which achieved good stress relief results.