Seismic Resilience Analysis of Circular Tunnel in Soft Soil Deposits

The seismic resilient infrastructure should have the capability to reduce the damage induced by earthquakes and minimize subsequent losses with an effective recovery. This study presents a probabilistic approach to evaluate the seismic resilience of the circular tunnel in soft soil. Typical circular tunnels in Shanghai are adopted as a case study, and the corresponding numerical model is established by ABAQUS. A series of ground motions are selected and scaled from 0.1 g to 1.0 g to perform non-linear dynamic analysis, aiming to obtain the tunnel responses under increasing levels of ground shaking intensity. Fragility curves are generated at the free-field ground surface, considering the main sources of uncertainties. Furthermore, based on the proposed fragility curves and the existing empirical tunnel restoration functions, the development of resilience index (Re) with the peak ground acceleration (PGA) at the free-field ground surface for circular tunnel is evaluated and quantified. The results show that this type of tunnel is good of seismic resilience.