INVESTIGATION ON TUNNELING METHODS FOR LARGE SECTION TUNNEL WITH SHALLOW OVERBURDEN

Abstract

It was found from researches on construction cases in Japan and overseas that one of the most effective tunneling methods for a large section tunnel with shallow overburden is installing the roof to stabilize the section against the overburden before excavating the ground. Examples for installation of tunnel-roof are connecting several small-section tunnels, which is common in China and France, utilizing a box-shield and combining shields by means of the shield-tunneling technology that is remarkably improved, and NATM.
In this paper, these tunneling methods are proposed and their effectiveness, advantage and disadvantage, applicability, and cost efficiency are reported.