二次动压巷道煤柱宽度优化研究

Optimization research on coal pillar width of secondary dynamic pressure roadway

为保障受二次动压影响巷道的围岩稳定性,沁新煤矿运用岩体极限平衡理论计算了煤柱宽度的合理取值范围,同时采用FLAC3D软件分别模拟了煤柱宽度为6、8、10、12、15m时,巷道超前邻近工作面40 m以及超前本工作面40 m时,巷道受一次动压影响、二次动压影响时的垂直应力分布状态,提出了强力锚杆索组合支护,并进行了现场应用及围岩表面位移监测。结果表明:(1)安全系数取0.15~0.35时,研究巷道煤柱宽度宜取7.57~8.89 m;(2)对比数值模拟结果发现,煤柱宽度为8 m时,煤柱不仅可发挥其承重作用,而且能保障煤柱应力集中区最小,煤炭资源浪费最少;(3)受一次动压影响,巷道在邻近工作面超越其110 m时,围岩变形趋于稳定,巷道变形在安全范围内,仍可服务于本工作面的回采。

In order to ensure the stability of the surrounding rock of the roadway affected by the secondary dynamic pressure, the reasonable value range of the coal pillar width was calculated by using the limit equilibrium theory of rock mass. At the same time, the FLAC3D software was used to simulate the vertical stress distribution when the roadway was 40m ahead of this and adjacent working face, and effected by twice dynamic pressure with coal pillar widths of 6 m, 8 m, 10 m,12m and 15m respectively. The combined support of strong bolts and cables was proposed for field application and the displacement of the surrounding rock surface was monitored. The results showed that:(1) When the safety factor was 0.15 ~0.35, the width of the coal pillar in the study roadway should be 7.57 m ~ 8.89 m;(2) Compared with the numerical simulation results, it was found that when the width of the coal pillar was 8 m, the coal pillar could not only play its load-bearing role, but also ensured the smallest stress concentration area of the coal pillar and the least waste of coal resources;(3)Affected by the primary dynamic pressure, when the adjacent working face exceeded 110 m, the surrounding rock deformation tended to be stable, and the deformation of the roadway was within a safe range, which could still serve the mining of this working face.