Earth fissures pose a significant risk to the seismic safety of underground structures at earth fissure sites (USEFs), particularly for large-scale underground frame structures such as subway stations. To date, the failure mechanism of USEFs has only been analyzed qualitatively and requires further comprehensive investigation. Moreover, the existing failure prediction methods for USEFs are complicated, challenging to execute, time-consuming, and incur significant financial costs, necessitating the establishment of a simple and efficient failure prediction method. This study conducted a shaking table test on a USEF to investigate the dynamic response of earth fissure sites and the seismic damage characteristics of a USEF. Based on the experimental results, a tailored pushover analysis method was developed to predict the seismic failure of the USEF and was applied to reveal its underlying seismic failure mechanisms. It was found that low-frequency ground motions are significantly amplified at the earth fissure site and that the acceleration amplitudes at the hanging wall and footwall are nonuniform. This nonuniform acceleration leads to significant extrusion and separation between the hanging wall and footwall. The extrusion causes the soil to rise, exerting additional axial pressure and bending moments on the lateral resistance members. These additional forces lead to uneven internal force distributions within the USEF, highlighting that structurally weak members are prone to failure and accelerating structural damage. The bottom column at the hanging wall is the critical seismic member of the USEF, which requires focused reinforcement and monitoring to increase resilience. The tailored pushover analysis method accurately represents the deformation characteristics at earth fissure sites. The method captures distinct structural destruction patterns, enhancing its utility in seismic failure prediction for USEFs.

With the development of the Chinese economy and society, the height and density of urban buildings are increasing, and large underground transportation hubs have been constructed in many places to alleviate the pressure of transportation. Commercial buildings are usually developed above the large underground transportation hubs, so the underground structures may have very shallow depths or no soil cover. The seismic response and damage mechanisms of such underground structures still need to be studied. In this paper, an example of a project in China is taken as an object to analyze the seismic response and damage mechanism of the structure after simplification. The spatial distribution of deformations and internal forces of such structures and the location of the maximum internal forces are obtained, and the effect of the frequency of seismic motions on the structural response is obtained. Finally, an elastoplastic analysis of such structures is carried out to assess the damage location and the damage evolution process.