Abstract:

Shouxihu tunnel in Yangzhou, which crosses underneath the Grade 5A scenic area, is a singlebore doubledeck tunnel. In the paper, SES is applied to simulate the ventilation air volume and pollutant concentration inside the tunnel, so as to protect the environment near the tunnel portals. Longitudinal ventilation is determined to be applied for both the upper tunnel tube and the lower tunnel tube, considering the range of the pollutant dispersion and the environmental sensitive points near the tunnel portals. The layout of the crosssection of the tunnel is optimized and smoke passages are arranged in the shieldbored tunnel section and part of the cutandcover tunnel section, considering the fast sediment of the smokes. The key smoke exhaust mode adopted doubles the available safe evacuation time. Forced draught blowers are applied to the emergency staircases of the upper tunnel tube and the lower tunnel tube respectively, which ensures that no smoke can enter the nonaccident tunnel tube and in turn improves the safety of the passengers significantly.

Key words: Shouxihu tunnel in Yangzhou, singlebore doubledeck tunnel, ventilation system, ramp diversion, pollutant diffusion, smoke exhaust