新建隧道穿越既有隧道快速施工技术及应用——以巫山隧道下穿岳家岭隧道为例

Application of Rapid Construction Technology in Newly-Built Tunnel Crossing Existing Tunnel——A Case Study of Yuejialing Tunnel under Wushan Tunnel

郑万铁路重庆段隧道工程多次下穿沪蓉高速公路,面临施工工法复杂、分部开挖单位多、作业空间狭小等不利因素,导致机械化掘进慢、施工成本高。以巫山隧道下穿沪蓉高速岳家岭隧道施工为例,在满足既有结构安全稳定前提下,经方案比选、结构安全验算及论证,增强预支护体系和优化分部开挖单位,采用上台阶中隔壁法和台阶法相结合的开挖支护方法施工,建立既有构筑物和新建隧道监控量测管理机制,解决机械开挖空间狭小问题,实现安全快速下穿既有高速公路隧道施工。

The tunnel project of Chongqing section of Zhengwan Railway has been running down the Shanghai-Chengdu expressway for many times,confronted with unfavorable factors such as complex construction method,many excavating units in diff erent sections,and small working space,which leads to slow mechanized tunneling and high construction cost.In the construction of Shanghai-Chengdu YueJiaLing tunnel crossing under Wushan tunnel,the rapid construction technology is applied after the scheme comparison,structural safety checking and argumentation,and under the premise of satisfying both security and stability of structure:enhancing the preliminary support system,optimizing the division of the excavation,adopting the excavation support method by combining adjoining and bench cut method on the steps,establishing the management mechanism of monitoring and measuring the existing structures and the newly-built tunnel.The technology can ensure the safe and fast underpass of the existing highway tunnel.