Resilience assessment of tunnels: Framework and application for tunnels in alluvial deposits exposed to seismic hazard

Abstract

Transport infrastructure is the backbone of the economy and society, while at the same time is exposed to multiple hazards. Previous natural disasters, including earthquakes, had a significant impact on transport networks with severe consequences for the users and supply chain. In this context, the resilience assessment of critical assets such as tunnels is of paramount importance for increasing safety and maintaining their functionality in seismic-prone areas. This study presents a practical resilience assessment framework for tunnels subjected to earthquakes. The proposed framework combines fragility and restoration functions, for assessing the robustness of tunnels exposed to different seismic scenarios, and the rapidity of the recovery considering different damage levels. The framework is applied to circular tunnels in alluvial deposits. A life-cycle resilience index is estimated, and the effects of soil conditions, tunnel burial depths, construction quality, and aging of the tunnel lining, on the resilience quantifications are examined and assessed. This effort contributes to the resilience-based design and management of tunnels and underground transport networks, and hence, facilitates decision-making and efficient allocation of resources by consultants, operators, and stakeholders.