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.

The structural safety of the utility tunnel is adversely affected when it passes through an area with earth fissures. Using the comprehensive tunnel project at the f7 earth fissure site in Xi'an as the engineering prototype, finite element simulation was employed to investigate the mechanical responses and deformation laws of the utility tunnel under different relative positions of earth fissures and deformation joints. Simultaneously, the deformation mechanism of a utility tunnel crossing an earth fissure was explored by using theoretical analysis. The results show that the influence of the earth fissure on the surface deformation of the hanging wall is greater than that of the footwall, and the main deformation is near the earth fissure. In addition, because the rigidity of the utility tunnel greatly exceeds that of the soil, the surface deformation at the earth fissure does not show a sudden change in form as dislocation generated by the hanging wall and footwall. Earth fissure movement mainly affects the stress change in the utility tunnel in the crossing ground fissure section. Moreover, the void area will be generated by the dislocation of the earth fissure near the earth fissure position at the bottom of the utility tunnel, which is not conducive to the stress of the utility tunnel. The research results contribute to optimizing the design of utility tunnel projects and enhancing the structural safety of tunnels. Additionally, they provide important reference points for the maintenance and management of comprehensive utility tunnels, enabling timely identification and resolution of the impacts of earth fissures on tunnel structures, thus ensuring the long-term stable operation of the tunnels.