城市浅埋超大断面隧道的开挖方法探讨

重庆市轨道交通三号线红旗河沟车站位于繁华城区中心，周边环境复杂，隧道最大断面达730m2，覆盖岩层仅8.6m厚，覆跨比约为0.4，为典型的超浅埋超大断面隧道。根据工程类比，施工前对几种开挖方法进行了多次的对比分析与探讨，认为均有各自的优缺点，每种方法都得采取有效施工措施才能实现，几种开挖方法的探讨为大断面隧道的施工提供了借鉴。

Discussion on Excavation Methods of Shallow-covered Extra-large Cross-section Urban Tunnels

Hongqihegou station on No.3 line of Chongqing mass rapid transit system is located in the central busy urban area, where the surrounding environment is complex. The maximum cross section area of the station tunnel is 730m2, the cover of the station tunnel is 8.6m and the cover span ratio of the station tunnel is about 0.4. Therefore, the station tunnel is a typical extra shallow covered extra large cross section tunnel. Prior to commencement of the works, comparison and contrast are made on several optional excavation methods of the station tunnel and conclusion is drawn that each excavation method has its own advantages and disadvantages and that effective construction measures must be taken for each excavation method so as to achieve successful excavation. The discussions on the optional excavation methods of the station tunnel can provide reference for the construction of similar extra large cross section tunnels in the future.