Abstract:

Gaoyangzhai tunnel on Yichang～Wanzhou railway is 4730m long. The exit portal section of Gaoyangzhai tunnel, which consists of largespanned doubletrack tunnel section and swallowtailshaped tunnel section, goes through such complex geological conditions as talus, cumulated ground and fracture zones containing karst and rich water. On basis of presenting the determination and execution of the construction plan for the largespanned section and the swallowtailshaped section of Gaoyangzhai tunnel, the author describes the construction technology for largespanned tunnels in complex geological conditions and presents the issues to which attention should be paid during tunnel construction.