New waterproof structure for New Austrian Tunneling Method

摘要

Along with increases of tunnels and other social overhead capital, reduction of total costs is an urgent necessity. New Austrian Tunneling Method (NATM) is increasingly used to construct tunnels in urban districts as well as in mountainous areas because the method is rational and economical. Cracks on lining concrete and water leakage are a serious problem, and measures are needed to minimize maintenance and repair works since tunnels are difficult to repair while in service. The authors developed a system that enables smooth application of lining sheets for NATM, free from the effects of unevenness on sprayed concrete surface. This system can reduce cracks on lining concrete and produce highly watertight tunnel structure, and thus can prolong the service life of the tunnel and reduce the maintenance and repair costs. This paper describes the concepts and execution methods of this system.