Damage evaluation and resistance enhancement technologies for highway tunnels under high-power fire conditions

The operation of highway tunnels involves numerous complex challenges, which become particularly pronounced during extreme disasters such as fires. This study takes the Qinling Tiantai Mountain Highway Tunnel as the engineering background and focuses on damage evaluation and resistance enhancement technologies under fire scenarios. First, a coupled thermal-mechanical numerical model of the highway tunnel is established using FDS and ANSYS co-simulation to identify the most hazardous cross-section under a 100 MW fire source. Subsequently, a resilience quantification model is developed based on strain energy, and a resilience evaluation system for highway tunnels under fire conditions is constructed by selecting appropriate recovery functions and recovery times to calculate the resilience index. Finally, the effectiveness of five protective measures, including fire-resistive coatings, fire-resistive panels, concrete sacrificial layers, concrete types, and sprinkler systems, in enhancing the fire resilience of the lining structure is compared and analyzed. This study introduces resilience theory into the field of tunnel fire safety, and the proposed resilience evaluation method can provide a theoretical basis and important references for the disaster prevention design, disaster assessment, and post-disaster recovery of highway tunnels.