Abstract: Abstract: The FDS was used to simulate the lateral point smoke exhaust system in a double-deck shield road tunnel, and the influence of smoke outlet area, space, smoke outlet opening scheme and longitudinal ventilation on the smoke exhaust system is studied. The results show that without longitudinal ventilation, the area within 3 m2 to 5 m2 and space between 60 m and 100 m of smoke outlets have little effect on the effectiveness of smoke exhaust after the fire has stabilized. As the longitudinal ventilation velocity increases and more upstream smoke outlets opens, the smoke exhaust efficiency decreases significantly. The smoke exhaust efficiency for the upper and lower exhaust outlets of the double-deck tunnel is basically the same, and the total smoke exhaust efficiency of the lower tunnel is slightly higher than that of the upper tunnel. It is proposed that in the event of a 20 MW fire in this double-decker tunnel, smoke exhaust is most effective when the longitudinal ventilation velocity is 2 m/s, the smoke outlet space is 60 m, the smoke outlet area is 4 m2, and two upstream and four downstream smoke outlets are opened.

Key words: Key words: double-deck shield tunnel, lateral point smoke exhaust, numerical simulation, smoke exhaust efficiency