Design Approach for Improving Fire-Resistance Performance of Tunnel Lining Based on SiO2 Aerogel Coating

Abstract

Tunnel fires often cause huge damage to the lining structure. In order to avoid cracking and spalling of the lining in the case of large-scale tunnel fires and thus ensure the safety of the tunnel, a new tunnel-fire-resistance approach was proposed based on the SiO2 aerogel material. Numerical simulation models of a tunnel were established and the internal temperature distribution of the lining was studied to verify the feasibility of this new approach. The thermal insulation effect between the SiO2-aerogel-coated lining and the conventional lining under simulating fire was comparatively analyzed. After 1 h of simulating fire, the temperature of the 50-mm-thick concrete on the surface layer of the conventional lining exceeded 600°C. This temperature was enough to cause serious cracking, spalling, and even bursting of the tunnel lining. For the SiO2-aerogel-coated lining, the internal temperature of the lining was kept below 200°C, and most of the area was even below 100°C. The results indicated that the fire-resistance performance of the tunnel lining can be significantly enhanced by using the SiO2 aerogel coating. In the future, it will have excellent application potential in the field of tunnel-fire protection.