Abstract:

Doublearch highway tunnels can be divided into four types, i.e., doublearch tunnels with straight monolithic center pillars, doublearch tunnels with straight composite center pillars, doublearch tunnels with curved monolithic center pillars and double arch tunnels with curved composite center pillars. These four types of doublearch tunnels are compared in terms of the center pillar structures, the span of the doublearch structures and the structural waterproofing and drainage of the tunnels. The application scopes and advantages and disadvantages of different types of doublearch tunnels are expounded, with the advantages of doublearch tunnels with straight composite center pillars used in complex topographic conditions and waterrich areas being focused. The application technology for doublearch tunnels with straight composite center pillars are presented, on basis of engineering cases, in terms of design, construction method and key position construction. The paper can be served as reference for similar projects in the future.

Key words: double arch tunnel, center pillar, waterproofing and drainage of tunnel, complex topographic conditions, construction technology