Abstract: Aiming at the smoke exhaust scheme of the tunnel fire in the metro section longer than 20 km, based on the Guangzhou Metro Line 18 project, the numerical simulation is used to analyze the temperature below the tunnel vaults and the flow velocity in the tunnel under the smoke extraction scheme when subway trains stop at different positions in the section. The result shows that the smoke extraction scheme can control the temperature in the tunnel well, and the flow velocity in the tunnel also meets the requirements of greater than 2 m/s and less than 11 m/s in the specification. The research result provides a guarantee for the safe operation of the tunnel and provides a scientific reference for related projects .

Key words: metro, super-long section, tunnel fire, smoke exhaust scheme