Abstract: In order to explore the fire characteristics of curved tunnels and study the influence of curvature on the smoke spread of curved tunnel fires, the fire dynamics simulation software PyroSim was used to study the critical wind speed, temperature distribution, smoke spread law, and roof temperature attenuation law of curved tunnels with different curvatures. The results show that under the same fire source power and fire source location, the critical wind speed is positively correlated with tunnel curvature; Due to the special resistance along the wall, the propagation speed of high?temperature smoke inside the curved tunnel is faster, and as the duration of the fire increases, the difference in smoke propagation speed between the two sides of the tunnel increases; The temperature attenuation of the roof in a fire is positively correlated with curvature, and a prediction model for roof temperature attenuation with curvature of 0.6%, 0.5%, 0.3%, 0.25%, and 0.14% is provided.

Key words: curved tunnel, tunnel fire, PyroSim, curvature, critical wind speed, roof temperature