深部倾斜煤层沿空掘巷围岩变形特征与控制技术研究

Research on surrounding rock deformation characteristics of gob-side entry driving in deep inclined coal seam and its control technology

通过对深部倾斜煤层沿空掘巷掘、采两阶段围岩应力场与位移场的分析,揭示了该类巷道围岩非对称大变形特征:窄煤柱帮与底板变形量远大于实煤体帮及顶板,巷道整体断面收敛率大。产生该变形破坏特征的原因:1)巷道埋深大,围岩处于较高的应力环境中;2)护巷煤柱宽度及支护阻力过小,使其过早进入残余承载阶段;3)无支护底板作为变形破坏能量主要释放通道,加剧了巷道顶帮围岩整体下沉。通过对不同宽度护巷煤柱方案的数值模拟,合理确定了试验巷道护巷煤柱宽度及试验巷道支护技术与参数。工程实践表明,采用新支护技术后,巷道窄煤柱与底板非对称变形大变形得到了有效控制,保持了巷道长期稳定。

The paper has analyzed the stress field and displacement field of surrounding rock of gob-side entry driving in deep inclined coal seam at driving stage and mining stage, and revealed the asymmetric large deformation characteristics of such roadway. The deformation amount of narrow coal pillar rib and floor was greater than that of solid coal mass rib and roof, and the convergence rate of whole roadway section is large. Reasons contributing to such deformation and failure characteristics have been pointed out as below：1） As the roadway is buried in great depth, the surrounding rock is lo-cated in high stress environment;2） The width of roadway protection is not enough and the supporting resistance is too small, which make the surrounding rock enter the residual bearing stage too early;3） Unsupported floor as the main releasing channel for deformation and failure energy, has intensified the whole subsidence of roof surrounding rock. The paper has reasonably determined the width of roadway protecting coal pillar and the supporting technology and parameters of testing roadway. Engineering practice has showed that after adopting new supporting technology, the asymmetric large deformation of narrow coal pillar and floor has been controlled effectively, which has maintained the long term stability of the testing roadway.