Abstract:During the Kobe earthquake in Japan, different degrees of earthquake damage occurred on the subway underground structures. Only one zone of the standard section of Daikai station totally collapsed, while the other zones of Daikai station, its running tunnels and other subway underground structures did not have serious earthquake damage. In this paper, the earthquake damage responses of the standard section, central hall and running tunnel structure of Daikai station were analyzed based on nonlinear finite element analyses which can reasonably simulate the damage of underground structures. Numerical results indicate that different width of structural cross section and burial depth lead to different overlying earth pressure on the structures at the standard section, central hall section and running tunnel section. The different overlying earth pressure generated different axial compression ratio of the three structural columns. In addition, the three structures with different lateral racking stiffness had different degree of damage and stiffness degradation, and further led to different lateral racking deformation. Eventually, the columns of Daikai station standard section destroyed due to the excessive relative deformation under the high axial compression ratio, which caused the total collapse damage to the entire frame structure. On the contrary, the columns of central hall and running tunnel section have not destroyed because there were not excessive relative deformation under the lower axial compression ratio, which kept the bearing capacity of the entire frame structure.