Abstract
The Shin-Kanmon Undersea Tunnel is the railway tunnel on the Shinkansen, the thirdundersea tunnelconnecting Honshu and Kyushu across the Kanrnon Straits, its total length being 18.7km. Although theunderwater portion is 880m long or only five per cent of the total, it was very difficult to construct the tunnelbecause of the clayey and crashed fault zone underwater, abount 30m in width.
This paper deals with the surveys made on the underwater portion and the application of the results forthe selection of the route and for the planning of the construction of the tunnel.It refers to the surveymethods adopted-super-sonic and seismic wave prospecting, and long horizontal boring-as well as to the pilottunnel.
