大跨度开切眼围岩强化控制技术研究

Study on intensified control technology of large span open-off cut surrounding rock

为掌握厚煤层大跨度开切眼破坏特征,并对围岩稳定性进行有效控制,对庞庞塔煤矿705工作面大跨度开切眼掘进过程中出现的巷道两帮移近量大、顶板下沉剧烈等情况进行分析,通过分析围岩变形破坏的诱因,结合锚索桁架对顶板的支护作用机理,提出了以锚网索+桁架联合支护为基础的大跨度强化梁控制技术。应用结果表明:导硐开挖期间巷道顶底板最大移近量为90 mm,两帮最大移近量为100 mm,导硐开挖相对稳定期为15天左右。巷道扩帮期间顶底板最大移近量为95 mm,两帮最大移近量为65 mm,顶板在20天左右即能达到稳定,两帮在10天左右即能达到稳定,围岩变形量得到了有效控制。

In order to have the failure features of the large span open off cut in the thick seam and to effectively control the surrounding rock stability,an analysis was conducted on the high convergence between the two sidewalls,serious roof subsidence and other conditions occurred in the driving process of the large span open-off cut in No. 705 coal mining face of Pangpangta Coal Mine. With the analysis on the deformation and failure inducements of the surrounding rock,in combination with the support role mechanism of the anchor truss to the roof,a large span strengthened beam control technology was provided based on a bolt / steel mesh / anchor + truss combined support. The application results showed that during the excavation period of the pilot hole,a max convergence between the roof and floor of the gateway was90 mm,a max convergence between the two sidewalls was 100 mm and the relative stable period of the pilot hole excavation was about 15 days. During the reaming period of the gateway,a max convergence between the roof and floor was about 95 mm,a max convergence between the two sidewalls was 65 mm,the roof could be stabilized 20 days,the two sidewalls could be stabilized about 10 days and the deformation of the surrounding rock could be effectively controlled.