沿空留巷“内支-外卸”围岩控制技术研究与应用

Surrounding rock control technology combining internal support and external pressure relief in gob-side entry retaining

为解决现场实际中沿空留巷受采动影响围岩变形破环严重问题,以山西晋城东峰矿为工程背景,分析了沿空留巷不同阶段覆岩运移规律,明确了围岩控制的重点。确定了采用“内支-外卸”的协同控制方式,采用理论分析、现场应用与监测的手段着重对巷旁柔模混凝土支护与顶板超前爆破预裂卸压进行了设计、分析与效果检验。研究结果表明,沿空留巷巷道在滞后工作面100 m范围内巷道变形速度较大,柔模墙体在滞后工作面200 m范围内压力变化较大并达到最高值,应为维护重点;现场优化后的巷旁支护体能够满足巷帮的承载能力;柔模混凝土墙巷旁支护和超前爆破预裂切顶卸压协同发挥作用,在降低采动应力影响、改善留巷应力环境的同时提高了巷帮的支护强度,有效地提高了留巷围岩的稳定性。

To control the serious surrounding rock deformation induced by mining in gob-side entry retaining,we take Shanxi Jincheng Coal Mine as the engineering background,to analyze the overlying rock movement law in different stages in gob-side entry retaining,clarified the focus of the surrounding rock control,determined to the synergistic control way of internal support and external pressure relief,and finally,used theoretical analysis,on-site application and monitoring to design,analyze and validate the flexible formwork concrete road-side support and the advance roof pre-splitting pressure relief blasting.The results show that,the gob-side entry deformed quickly within 100 m lagging behind the working face,and the pressure change of the flexible formwork wall was large and maximized within 200 m lagging behind the working face,so these should be the key point of maintenance;the optimized road-side support body met the bearing capacity of the roadway sidewall;the roadway support of the flexible formwork concrete wall and the advance roof pre-splitting pressure relief blasting worked synergistically to reduce the impact of mining stress,improve the stress environment and the support strength of the retained entry,which effectively improved the surrounding rock stability of the retained entry.