ABSTRACT
This chapter introduces the present state of design and construction technologies for the mountain tunneling method in Japan. Seventy percent of the land in Japan is mountainous; and therefore, the plains are densely populated due to the limited land area. To counteract this problem, numerous railway and roadway tunnels are built. The country of Japan consists of many islands, including the main island of Honshu. Honshu is connected to both the northern island of Hokkaido and the southern island of Kyushu by undersea tunnels where traffic demands are high. In Japan, steel supports are generally used along with other countermeasures when a large deformation develops or when the ground is unstable. In such cases, steel supports also serve to reinforce the shotcrete. A new support is under development along with a new construction method. The new development in recent research is introduced here in addition to high-strength shotcrete and steel fiber reinforced concrete.
