深部大跨度硐室顶部卸压应力控制机理及数值模拟研究

深部大跨度硐室在高应力下常出现明显的围岩变形破坏,严重的会影响矿井的正常生产甚至引发事故。以新庄煤矿机头硐室受围压破坏变形为工程背景,分析机头硐室巷变形破坏的地质因素,提出采用顶部卸压法进行硐室维护的方案,并模拟卸压前后围岩应力及变形的变化。数值模拟结果表明顶部卸压后,硐室围岩应力重新分布,围岩应力下降和向深部转移;硐室顶底板围岩铅垂应力及两帮水平应力均减小,顶板围岩铅垂应力平均减少61.5%,底板浅部0-2 m区间内围岩铅垂应力接近0,水平应力平均减小75.4%。从模拟结果看,顶部卸压实施后有利于机头硐室的长期稳定。

Stress control mechanism and numerical simulation study on top pressure relief for large-span chamber protection in deep strata

The obvious displacement and deformation occurs often in deep chamber under high stress,which maybe affect the normal production,and what’s worse,cause safety accident when displacement and deformation are severe in coal mine. In this paper,on the background of displacement and deformation in head chamber of Xinzhuang Coal Mine,the geologic factors that effect the displacement and deformation of head chamber were analyzed,the design precept by applying top pressure relief of large-span chamber was put forward,and the stresses on the surrounding rocks and deformation of chamber were simulated before and after the pressure relief. Numerical simulation results showed that the stresses on the surrounding rocks were redistributed,which decreased and transferred to the deep rock; both horizontal stresses and vertical stresses were declined on roof and floor of chamber,the vertical stress of the roof rock was reduced by 61. 5% and the stress was close to zero on the surface in 0-2 m depth of the floor,the horizontal stress of surrounding rock in two sides were reduced by 75. 4%. The results of numerical simulation show that it is useful for long-term stability of the chamber.