Spatiotemporal evolution analysis of urban lifeline infrastructure disaster chain network based on numerical simulation and cascading effects

Under the backdrop of frequent extreme climate events, urban lifeline infrastructures are becoming highly interdependent, and the propagation path of the disaster chain is becoming increasingly complex. To reveal the spatiotemporal evolution of lifeline infrastructure disaster chain network (LFSCN) under extreme rainfall events, a coupled urban flood numerical model integrating the Storm Water Management Model (SWMM)—a widely used hydrological-hydraulic simulation tool for urban drainage—and TELEMAC-2D, a two-dimensional hydrodynamic model for simulating surface flow, was developed. Based on the spatial relationships between 20 types of lifeline infrastructure and disaster-bearing bodies, a weighted and directed network was constructed, with 0.5 m water depth defined as the threshold for cascading failures. The results show that under extreme rainfall events, the LFSCN undergoes a staged yet nonlinear degradation process, characterized by a transition from localized disruptions to system-wide cascading failures. Among various infrastructures, the influence of the power supply was relatively prominent, and its failure was more likely to cause the degradation of multi-system linkage. Upon reaching stabilization, the disaster chain network damage index (DCNDI) under 50 yr, 100 yr, 200 yr, and ZZ 720 rainfall events were 0.20, 0.37, 0.45, and 0.81, respectively. The proposed integrated framework, combining flood simulation with network analysis, not only quantifies network damage but also captures cascading propagation processes, providing scientific support for identifying critical nodes, informing infrastructure optimization, and strengthening urban resilience and emergency preparedness.