Abstract: Abstract: The paper focuses on the fire risk caused by the spilled liquid fuel in tunnels. The small-scale test platform with adjustable longitudinal and transverse slopes was established to study the spillage profile, spillage width and area. Meanwhile, the fire tests were carried out to investigate the impact of the fuel depth on the heat release rates. The results indicate that under the longitudinal slopes, the spillage width and area decreases as the slopes become great. When there are both longitudinal and transverse slopes, the liquid fuel spills towards the tunnel sidewall, and as a result, the spillage length and area decrease. In addition, the average depth spilled liquid investigated in this work is 2 mm, and the heat release rates of the fuel under this depth is 30%~50% of the theoretical values which are obtained by using a deep fuel. Based on the above achievement, the potential heat release rates caused by the spilled liquid fuel fires can be evaluated. The finding is that when the transverse slopes increase from 1% to 2% under a given longitudinal slope of a tunnel, the potential heat release rates of the fires caused by the spilled liquid fuel may be decreased by 1/2.

Key words: Key words: sloped tunnel, liquid fuel leakage, spilled liquid fire, heat release rate