挤压性围岩隧道大变形机理及控制技术

Large Deformation Mechanism and Control Technology of Squeezing Surrounding Rock Tunnel

软岩大变形一直是隧道施工中一个难题,处理不当将会严重影响隧道的安全、工期、质量和成本,挤压性围岩大变形由于国内外案例少,缺乏相关经验,进一步增加了施工难度。本文以玉磨铁路甘庄隧道为依托,通过分析地应力、地质构造、地层岩性确定了大变形发生的机理;根据大变形发生机理确定了相应的控制技术,包括三台阶变种短台阶开挖技术、压钢拱架变形控制技术、破碎带高速超前注浆技术、让压填充层变形控制技术等,通过一系列针对性的措施,成功控制住了围岩变形,并且提高了施工效率,可为类似的工程提供参考。

Large deformation of soft rock is always a difficult problem in tunnel construction.Improper handling will seriously affect the safety,construction period,quality and cost of the tunnel.Due to the lack of cases at home and abroad,and the lack of relevant experience,the large deformation of squeezing surrounding rock further increases the construction dfficulty.This paper is based on Ganzhuang Tunnel of Yumo Railway.The mechanism of large deformation is determined by analyzing in-situ stress,geological structure and formation lithology.According to the mechanism of large deformation,the corresponding control technology is determined,including three-step variant short-step excavation technology,deformation control technology of pressed steel arch,high-speed advanced grouting technology of broken zone,deformation control technology of yielding flling layer,etc.Through a series of targeted measures,the deformation of surrounding rock is successfully controlled,and the construction efficiency is improved.It can provide reference for similar projects.