中老铁路会富莱隧道软岩大变形控制技术研究

Study on Control Technique for Large Deformation of Soft Rocks in Huifulai Tunnel of China-Laos Railway

中老铁路会富莱隧道位于老挝琅勃拉邦地质缝合带,在隧道开挖期间,出现了围岩大变形情况。针对会福莱隧道围岩变形特点,文章分析了施工各阶段围岩的基本变形规律。经综合比较分析,提出采用圆形断面代替原类马蹄形断面的优化设计,并优化初期支护措施、合理增加变形量,同时采用短台阶快速初支成环施工工艺,有效控制了围岩变形,成功遏制住了会富莱隧道软岩大变形。通过比较,隧道衬砌断面设计优化在会富莱隧道软岩大变形控制中起到了决定性的作用。本次研究的软岩大变形技术已被中老铁路广泛应用,有效地解决了中老铁路琅勃拉邦地质缝合带隧道软岩变形的难题。

Huifulai Tunnel of China-Laos Railway is located in the geological suture zone in Luang Prabang of Laos,where the large deformation of surrounding rocks occurs during the tunnel excavation.According to the deformation characteristics of the surrounding rocks in Huifulai Tunnel,the basic deformation rules of surrounding rocks at each construction stage are analyzed.After comprehensive comparative analysis,the optimal design of circular section is proposed to replace the horseshoe-like section.In addition,the initial support measures are optimized,the deformation amount are reasonably increased.In the meanwhile,the construction technology of short-step rapid primary support ring is applied to effectively control the deformation of surrounding rocks and successfully restrain the large deformation of soft rocks in Huifulai Tunnel.By comparison,it can be seen that the optimization of tunnel lining section design plays a decisive role in controlling the large deformation of soft rocks in Huifulai Tunnel.The technique for large deformation of soft rocks studied in the research has been widely applied in China-Laos Railway,which effectively solves the problem of soft rocks deformation in the tunnel located at the geological suture zone in Luang Prabang of Laos.