The main purpose of this paper is to present a comprehensive novel methodology for fire analysis of infrastructures, viz. tunnels, via studying the effects of a major fire event on a case study tunnel, Louis Hippolyte Lafontaine Tunnel (TLHL). A weak thermo-mechanical coupling analysis is performed via a staggered scheme to evaluate the structural integrity of the precast tunnel caissons when subjected to fire. The effect of explosive spalling on the tunnel’s structural integrity was evaluated based on saturated steam pressure (SSP) with a cut-off peak. In-situ tests were conducted to assess the spalling of concrete in the TLHL and calibrate the spalling parameters in the numerical models. Both in-situ tests and numerical models predicted that spalling occurs approximately within two minutes in the fire event, which leads to a reduction in tunnel cross-section and structural capacity and impacts the long-term durability of the tunnel. In this study, based on the analysis results, passive fire protections were suggested to prevent the loss in structural integrity. Furthermore, the numerical simulations considering ground-structure interaction were carried out to firstly predict the response of ground and tunnel caissons, secondly, confirm the adequacy of the structural design of the tunnel, and finally, to ascertain the performance of fire protection when the tunnel is subjected to fire.

本文的主要目的是提出一种全面的基础设施火灾分析新方法，即。隧道，通过研究重大火灾事件对案例研究隧道 Louis Hippolyte Lafontaine 隧道 (TLHL) 的影响。通过交错方案进行弱热力耦合分析，以评估预制隧道沉箱在遭受火灾时的结构完整性。爆炸性剥落对隧道结构完整性的影响是根据具有截止峰值的饱和蒸汽压力 (SSP) 评估的。进行了现场测试以评估 TLHL 中混凝土的剥落并校准数值模型中的剥落参数。原位测试和数值模型都预测在火灾事件中大约在两分钟内发生剥落，这会导致隧道横截面和结构承载力的减少，并影响隧道的长期耐久性。在这项研究中，根据分析结果，建议采用被动防火措施来防止结构完整性的损失。此外，还进行了考虑地基-结构相互作用的数值模拟，首先预测了地基和隧道沉箱的响应，其次确认了隧道结构设计的充分性，最后确定了隧道发生时的防火性能。遭受火灾。