Study on Fire Smoke Spreading Characteristics in Asymmetric V-Slope Highway Tunnel
2. Center for Balance Architecture, Zhejiang University, Hangzhou 310007; 3. Zhejiang University Zhongyuan Institute,Zhengzhou 450000; 4. General Supervision Station of Construction Engineering Quality and Safety of Fuyang District, Hangzhou,Hangzhou 311400; 5. China Railway Siyuan Survey and Design Group Co., Ltd., Hangzhou 310000)
Abstract：
Underwater tunnels are often high at both ends and low in the middle, showing the "V" shape, with high fire risk. Therefore, mastering the characteristics of fire smoke spreading is the basis of fire emergency response,evacuation and rescue work. The Fire Dynamics Simulation software (FDS) is used to build the asymmetric V-slope tunnel fire model under the condition of natural ventilation, to study the spreading process of fire smoke under different combination of slopes, and to analyze the changes of smoke pressure and velocity at the tunnel portal on both sides of the tunnel. The results show that: after a fire occurs at the slope change point, the smoke spreading in the asymmetric V-slope tunnel presents the multi-phase spreading characteristics similar to that in the single-slope tunnel,but the smoke spreading velocity on the high slope side is slower than that in the single slope tunnel, while the smoke spreading velocity on the low slope side is faster, and the steady back-flow length of fire smoke is shorter; In the process of smoke spreading in the asymmetric V-slope tunnel, there exist three characteristic stages: flow field remodeling, forward dynamic cycle reconstruction, and maintaining stability; The maximum back-flow length and the steady back-flow length of the tunnel smoke on the low slope side and their corresponding moments are jointly affected by the tunnel slope gradients on both sides and the gradient difference, and there is a critical gradient difference of 4%. When the gradient difference is greater than 4%, the characteristics of fire smoke spreading will no longer be affected by the gradient difference.
LI Xiang1,
2 CHEN Xiaofeng1,
2 etc
.Study on Fire Smoke Spreading Characteristics in Asymmetric V-Slope Highway Tunnel[J] MODERN TUNNELLING TECHNOLOGY, 2023,V60(5): 111-119
2023, Vol. 60 