Assessment of fire-induced damage and restoration programme in Xinqidaoliang road tunnel

摘要

The characteristics of fire damage to Xinqidaoliang tunnel in China were investigated. The study revealed that the fire caused 856 m~3 of concrete peel-off, damage to 650 m of pavement and a 4% increase in cross-sectional area. According to the relevant regulations, the fire-affected zones were classified as grade Ⅳ (serious damage), grade Ⅲ (moderate damage) and grade Ⅱ (mild damage). In order to better understand damage characteristics and the safety of tunnel structures when subjected to fire, a numerical simulation was conducted to assess the safety of the tunnel under varying stress fields. The simulation results indicate that the crushing pressure on the inner and outer contour line of the lining significantly increased with an increase in damage level at all stress fields. Where the thickness of the tunnel vault was less than 34 cm or the loss exceeded 16 cm, the rate of increase of lining pressure was greatly amplified, inducing a significant stress build-up in the lining structure and hence seriously reducing the safety of the whole lining. Based on different damage situations, restoration strategies were also assessed.