Combination of Pre-developed Seismic Fragility Models for Bored and Cut-and-cover Tunnels

Abstract

This study aims to collect existing seismic fragility models for bored tunnels and cut-and-cover tunnels, classify them based on the shape and depth of installation, and analyze the changes of fragility curves for each category. The analysis included the methods used to develop the fragility models, the techniques employed to model the tunnel using both empirical and numerical approaches, and the earthquake input motions and damage index criteria used to compute damage probabilities. Furthermore, representative fragility models for each category were proposed by weighting the categorized models. For bored tunnels installed in rock formations, they exhibited relatively lower fragility compared to cut-and-cover tunnels. Based on these preliminary research findings, it was observed that the probability of damage decreases with increasing burial depth.