Damage to mountain tunnels in hazard area

Abstract

There are over one hundred mountain tunnels in the hazard area of the 1995 Hyogoken-Nambu earthquake. Over thirty tunnels were affected by the quake including minor damage. About ten tunnels required countermeasures. In the Rokko Tunnel of the Shinkansen, many shear cracks occurred in the arch crown. In the Bantaki road Tunnel, a portion of the lining concrete in the arch and side wall fell down. In the Shioyadanigawa Water Tunnel, some cracks occurred and it slipped 8 cm due to movement of the Yokoosan Fault. Generally, compared to the catastrophic surface damage, tunnel damage was not severe and most of the damage was found in fracture zones.