炭质板岩地层隧道施工要点及大变形防治措施

Key Points and Large Deformation Control in Construction of Tunnel in Carbonaceous Slate

为解决兰渝铁路木寨岭隧道鹿扎斜井通过高地应力炭质板岩地段隧道防坍和变形控制,从炭质板岩的特性、变形机制以及出现变形后的处治方法等方面进行研究,得出以下几个结论:炭质板岩属软岩范畴,遇水易软化;有水地段开挖后易出现坍塌,需做好超前支护和注浆止水;高地应力炭质板岩隧道收敛持续时间长,累计变形量较大;发生变形后,可采用封闭仰拱、长锚杆、径向注浆、增设套拱等措施进行处治。

In order to prevent collapse and control deformation of Luza inclined shaft of Muzhailing Tunnel on Lanzhou-Chongqing Railway located in carbonaceous slate,the author analyzes the behavior and deformation mechanisms of the carbonaceous slate,as well as countermeasures to control the deformation.The conclusions drawn are as follows： the carbonaceous slate is a kind of soft ground subject to softening when water is encountered;collapse is subject to occurring after excavation in water-bearing sections,therefore advance reinforcement and pre-grouting are needed;tunnels located in high-stressed carbonaceous slate are subject to long convergence period and large deformation;countermeasures such as installing invert to form a closed ring,long rock bolts,radial grouting and protection arch can be taken to control the deformation.