层状围岩隧道变形控制技术探讨与实践

Discussion and Practice on Large Deformation Control Technology of Tunnel in Layered Rock

根据兰渝铁路薄层板岩隧道的工程实践,在分析层状围岩大变形机理的基础上,研究采用微台阶仰拱快速施工法、单工序作业仰拱快速封闭法等控制围岩变形。分析表明,减小围岩变形总量主要有降低变形速率和快速封闭仰拱以缩短变形时间两种途径。微台阶仰拱快速施工法,下台阶与仰拱同步推进,缩短了初期支护封闭成环时间进而减小围岩变形持续发展。单工序作业仰拱快速封闭法采用边墙长锚杆降低围岩变形速率,采用铣挖机减小爆破对周边围岩和初支段的扰动,围岩变形控制效果好。

Based on the engineering practice of Lanzhou-Chongqing railway tunnel with thin layer slate and analysis of lay- ered surrounding rock large deformation mechanism, study is carried out on the micro-step inverted arch fast construction method, the single working procedure inverted fast closing method to control the surrounding rock deformation. The Re- search shows that there are mainly two kinds of ways to reduce the deformation of surrounding rock ： one is to reduce the to- tal deformation rate, and the other way is to shorten deformation time by fast closing inverted arch. Micro step inverted fast construction method, synchronous heading of bench excavation and inverted can shorten the initial support closed loop time and reduce the sustainable development of surrounding rock deformation. The single working procedure of inverted arch rap- id closure method makes use of side wall long anchor to reduce surrounding rock deformation rate, and the milling machine is adopted to alleviate the disturbance of blasting on the surrounding rock and initial support, which effectively controls the surrounding rock deformation.