偏压地形下大断面隧道进洞技术

云桂铁路达康隧道出口段为三线隧道,位于偏压地形中,由于隧道跨度大、仰坡高且石质破碎,地质构造复杂,进洞时受到滑坡、剥落、崩塌等边坡变形破坏的威胁。通过对三种施工方法的分析、对比,得出了这种偏压大断面隧道进洞的较为合理的明洞暗进法施工方案。实施过程中进洞施工比较顺利,没有发生大的塌方、滑坡,保证了施工安全,缩短了工期,取得了较好的经济效益和社会效益。

On the Inletting Techniques for Large-Cross-Section Tunnels Under Topography of Biasing Pressure

The Da-Kang Tunnel of the Yun-Gui Railway is a third-line tunnel,the inletting section of which is located in topography with biasing pressure.Owing to the fact that the tunnel is large in span and high in inverted slope,the rock of the site is much broken,and the geological composition of the site is complex,the inletting section of the tunnel faces the risks of being damaged by side slope deformation such as land slide,exfoliation and collapse.Through the comparison and analysis of three different construction methods,a comparatively rational open-cut-tunnel-concealed-lead-in construction scheme is obtained.In the process of the implementation of the scheme,the inletting construction is quite successful,with no serious collapse and land slide happening.The safe construction of the project is ensured,with the construction duration shortened and fairly good social and economic effects obtained.