Abstract: In the design of smoke control and exhaust system of long interval tunnel, the middle air shaft is usually set, but the setting of the middle air shaft is easily restricted by many factors, so the smoke exhaust can be used instead of part of the middle air shaft. In order to verify and expand the feasibility of the alternative scheme of smoke exhaust, the smoke control methods corresponding to three smoke exhaust setting schemes were analyzed theoretically. Based on a certain subway in Guangzhou, numerical simulation was conducted to verify the smoke control effects of three kinds of smoke control methods under different conditions. The results show that, when the single-side air supply is 1.6 m/s and the smoke exhaust volume is 140 m3/s, the fire can basically effectively control the smoke discharge in the middle ventilation section. When the fire is located near the air shaft or below the smoke outlet, the air speed of 1.4~1.6 m/s and the smoke exhaust volume of 140~150 m3/s can effectively control the smoke, which proves that the smoke exhaust can replace part of the middle air shaft reliability, and expands the applicability of the scheme.

Key words: long section tunnel, smoke exhaust, smoke flow, tunnel vault temperature, numerical simulation