Mountain Tunnels Damage in the 1995 HYOGOKEN-NANBU Earthquake

Toshihiro ASAKURA
Dr.Eng. Chief Engineer, Tunnel Engineering Group,
Structural Technology Development Div.,
Technological Development Dept.

Yutaka SATO
Engineer, Tunnel Engineering Group,
Structural Technology Development Div.,
Technological Development Dept.


More than 100 mountain tunnels were in service in and around the disaster area of the 1995 Hyogoken-Nanbu Earthquake. Although the influence of the earthquake was much less compared with that on surface structures, in 20 to 30 mountain tunnels, some influence of the earthquake was observed, and around 10 of those tunnels suffered remarkable damage needing repair and reinforcement. A large part of the damage locations in the suffered tunnels coincided with the locations of existing faults and fracture zones which had been recognized during construction and are the same characteristics that have been known in the past experiences.