复杂环境下特大断面既有隧道原位拆除扩挖施工技术研究

Research on In-situ Demolition and Expansion Construction Technology for Existing Tunnels with Large Cross Sections in Complex Environments

与我国经济发展同步迅速增长的交通隧道交通容量要求也越来越高,与此同时也对隧道改建扩建技术有了更高的要求。双向四车道乃至双向六车道公路隧道已经不能满足在经济发展较好的地区较大的交通量需求,因此急需将公路隧道建设成双向八车道以适应发展需求。隧道的扩建主要有两种形式:新增小间距隧道和原位扩挖,新增小间距隧道是在原有隧道附近进行施工,原位扩挖是在原有隧道的基础上进行扩建,通过扩挖或改建现有隧道空间来实现扩建,因此它改变了原来隧道的结构。文中结合中开高速公路项目在粤港澳大湾区的重要地位,结合区域发展、节约土地和近远期交通组织管理需求,对在建双线六车道隧道进行改扩建施工,通过综合分析采取原位单侧扩挖法施工,本项目地质条件复杂、技术难度大、施工风险高,且目前国内尚无类似大断面隧道拆扩案例经验,故通过实施总结了在既有隧道原位扩挖施工主要技术方法,为以后类似工程施工提供参考。

With the rapid growth of Chinese economic development,the traffic capacity requirements for traffic tunnels are also increasing,and at the same time,there are higher requirements for tunnel reconstruction and expansion technology.Bidirectional four lane or even bidirectional six lane highway tunnels can no longer meet the large traffic demand in economically developed areas,so it is urgent to build highway tunnels into bidirectional eight lane tunnels to meet development needs.There are two main forms of tunnel expansion:the addition of small spacing tunnels and in-situ expansion.The addition of small spacing tunnels is carried out near the original tunnel,and in-situ expansion is carried out on the basis of the original tunnel.Expansion is achieved by expanding or renovating the existing tunnel space,which changes the structure of the original tunnel.Based on the important position of the Zhongkai Expressway project in the Guangdong Hong Kong Macao Greater Bay Area,combined with regional development,land conservation,and short-term and long-term traffic organization management needs,the reconstruction and expansion construction of the double track six lane tunnel under construction is carried out.Through comprehensive analysis,the in-situ single side excavation method is adopted for construction.The geological conditions of this project are complex,the technical difficulty is high,and the construction risk is high.Moreover,there is currently no experience in dismantling and expanding similar large cross-section tunnels in China.Therefore,the main technical methods for in-situ excavation construction in existing tunnels have been summarized through implementation,providing reference for similar engineering construction in the future.