Probabilistic Seismic Resilience Assessment for Circular Shield Tunnels in Soft Soils Considering Vulnerability Model Uncertainty

As critical infrastructure supporting sustainable urban development globally, the seismic resilience evaluation of tunnels is paramount to metropolitan safety. This paper proposes a probabilistic seismic resilience analysis framework for tunnel structures in soft soils. By integrating vulnerability models and functionality functions, resilience metrics for shallow, medium-depth, and deep tunnels are obtained, revealing how these metrics evolve with seismic intensity. The research further investigates the impact of different vulnerability models on tunnel resilience, treating occurrence probabilities of different damage states as random variables. Resilience metrics incorporating multiple vulnerability models are derived based on the Dirichlet distribution. The results of the study show that tunnel resilience metrics increase progressively with greater burial depth. At PGA = 0.8 g, for example, the resilience metrics calculated using a single model are 0.907, 0.962, and 0.985 for shallow, medium-depth, and deep tunnels, respectively. When accounting for multiple vulnerability models, the composite resilience metric tends to align with results from models carrying higher weights. This work establishes a scientific decision-making basis for optimizing seismic tunnel design, post-disaster functional recovery, and urban infrastructure resilience management.