Full-process seismic simulation method for urban underground rail transit networks considering source-path-structure effects

Conducting seismic research on large-scale urban underground rail transit networks is a frontier topic in the development of resilient cities. However, existing studies excessively simplify the characteristics and physical mechanisms of regional seismic motion. A comprehensive seismic analysis method considering the whole process of source-path-structure has not been formed. Hence, to simulate the overall seismic response of urban underground rail transit network, this study proposes a process-based seismic simulation method for urban underground rail transit networks based on deterministic physical simulation. The proposed approach employs a kinematic hybrid source model in the Frequency-wavenumber (FK) domain to construct the seismic motion spatiotemporal field for the study site. The finite element method is used to determine the seismic response of the underground rail transit network. Taking the Tianjin underground rail transit network as an example, the proposed method is used to simulate the entire seismic response process from the source rupture to structural response analyzes. The dynamic response characteristics of the underground rail transit network under various intensities of near-fault seismic motion is analyzed. Additionally, the peak response distribution and potential damage risk assessments are obtained. The results show that the proposed method can reflect the characteristics of near-fault seismic motion, which means that the method could be used for the seismic disaster prevention and guidance for the urban-scale underground rail transit networks. The related research methods can provide references for urban seismic disaster relief, localized defense planning, and disaster scenario construction.