Selection of optimal intensity measures for fragility assessment of circular tunnels in soft soil deposits

This study aims to identify optimal intensity measures (IMs) for use in probabilistic seismic demand models (PSDMs) circular tunnels soft soil deposits. To this end, we performed an extended numerical parametric involving two-dimensional time history analyses of selected soil-tunnel configurations evaluate the response under transverse shaking. A series 18 IMs were and tested, corresponding free field conditions. The tested on several metrics, such as correlation, efficiency, practicality, proficiency, based number regression between damage measure (DM), studied tunnels. DM is defined ratio actual bending moment (M) capacitive (MRd) tunnel lining. results indicate that peak ground acceleration (PGA) at surface can be considered IM shallow tunnels, whereas velocity (PGV) both moderately deep Finally, various fragility curves constructed context PSDMs. findings serve a reference analysis deposits, toward more reliable quantitative risk (QRA), improved resilience, adaptability transportation networks.