Review on damage causes and disaster mechanism of Daikai subway station during 1995 Osaka-Kobe Earthquake

During the 1995 Osaka-Kobe Earthquake, different degrees of damages were observed in Daikai, Nagata, Sannomiya, Kamisawa and Shin-nagata subway station and running tunnels. Among them, the earthquake damages at Daikai subway station were the most serious. It is the first large-scale underground structure that almost collapsed in the earthquake, which has aroused people’s concern and attention to the seismic issues of underground structures. A large number of theoretical, numerical and experimental studies about the earthquake damages on Daikai subway station have been carried out. These have enhanced the comprehension of the earthquake damage mechanism and the failure mode of underground structures. However, most researches have not reached a consensus so far regarding the damages of Daikai subway station owing to that their conclusions are based on different analysis aspects, diverse collections of the relevant information and dissimilar analysis methods and models. The researches on earthquake damages at Daikai subway station are reviewed. The effect of seismic motion, site conditions and structural characteristics on the earthquake damages of Daikai subway station are summarized. Furthermore, further studies on the in-depth analysis of earthquake damages at Daikai subway station and the key seismic issues of the underground structures are proposed.