Study on Seismic Dynamic Failure of Tunnel-Soil- Frame Structure System through Shaking Table Test and Numerical Simulation

To investigate the dynamic response of an underground structure-soil-aboveground structure interaction system under seismic action, a shaking table test was conducted with a section of Zhengzhou Metro as the engineering background. A three-dimensional numerical model covering the aboveground and underground multi-structure system was established using ABAQUS. Four working conditions were designed, and three representative seismic motions were selected as input seismic waves. The variation characteristics of key parameters, such as acceleration, shear force, bending moment, and inter-story displacement angle, during the seismic response process of the tunnel and frame structure were systematically analyzed. The research findings indicate that significant dynamic coupling exists between the aboveground and underground structures, with the overall structural system playing a significant role in modulating the propagation path and energy distribution of seismic waves in the site. The acceleration exhibits a trend of attenuation in the near-field response and enhancement in the far-field response. The aboveground frame structure absorbs and dissipates substantial seismic energy in the near-field, while the underground tunnel structure induces amplification of vibration response in the far-field region. In the scenario with aboveground structures, the tunnel's acceleration response exhibits stronger spatial non-uniformity, with distinct points of amplification, reflecting the dynamic disturbance effect of the upper structure. In contrast, in the condition without the upper structure, the tunnel response is relatively symmetric and stable. Regarding force analysis, the inclusion of the aboveground structure improves the force distribution path of the tunnel, reduces the risks associated with sharp fluctuations in bending moments and stress concentration, and also delays and attenuates seismic input via the "energy storage-energy release" mechanism in the time domain, thus enhancing the overall seismic resilience and stability of the system. Moreover, the inter-story displacement angle of the aboveground frame structure is significantly affected by the underground structure, manifested as a weakening of shear stiffness in the lower floors and an increase in the concentration of deformation. The response differences expand significantly under different seismic spectra, showing that the underground structure enhances the system's sensitivity to seismic spectral characteristics. In conclusion, the interaction between aboveground and underground structures has a significant impact on seismic response in complex urban environments. Seismic design should fully consider these structural synergies to enhance the overall seismic performance and safety of the building group.