Abstract:

Xiaoyangshan tunnel is the first doublearched tunnel with superposed partition wall (“Superposed partition wall” is used in the paper to distinguish from the composite partition wall specified in “Design Specification for Highway Tunnel”) in China. Regarding the innovated tunnel structure, it is very important to select proper construction scheme and proper construction methods, which is the key to follow the design principles and to realize the design targets. In the paper, the determination of the construction methods (including the design principles and design methods and the general construction scheme) and the execution of the construction scheme (including the determination of proper distances between different working faces, execution of controlled blasting so as to minimize the influence on the completed lining and partition wall imposed by the construction of the subsequent tunnel and taking proper measures to overcome the asymmetrical loading of the firstexcavated tunnel). Furthermore, the key points of construction monitoring and waterproofing and drainage of the tunnel are expounded. The successful construction of Xiaoyangshan tunnel enriches the design of mountaincrossing tunnels.