Experimental Research On Fire Smoke Exhaust In Extra Long Immersed Tunnel

The fire is the biggest risk in long immersed tube tunnel. Fire smoke is a major cause of death, which will lead to serious consequences with uncontrolled or improper control. It becomes the core issue of the operation of disaster prevention and mitigation that Control of the tunnel lateral central exhaust system of smoke. This article focuses on solving the key problem of immersed tube tunnel operation ventilation and smoke exhaust.Through domestic and foreign research, theoretical analysis, numerical calculation and physical test and other means. This article focuses on 4 key technologies: Analysis of reasonable smoke exhaust gas in single group, Analysis of opening group number of smoke exhaust port, Analysis of open angle valve flue gas valve, Study on smoke control scheme under different longitudinal slope mode and put forward immersed tunnel smoke smoke control strategy under fire conditions. Provide technical support for smoke control strategy of the Hong Kong Zhuhai Macao immersed tube tunnel,and Provide the basis for preparation of "offshore immersed tunnel disaster prevention technology specialty". The main work is as follows:1) Analysis of reasonable smoke exhaust gas in single group. We must emit smoke for effective control of tunnel fire smoke. The smoke control effect is directly related to the reasonable smoke discharge quantity of the single group. Theoretical calculation and analysis of smoke gas quantity, numerical calculation of smoke exhaust gas in single group and analysis of the influence of increasing the smoke gas quantity on the flue gas control effect, we get the reasonable smoke volume when fire in immersed tunnel.2) Experimental study on opening angle of smoke exhaust valve. When the fire occurred In the tunnel, the monitoring center starts the axial fan to start the smoke exhaust. Under the conditions of determined open the number of smoke exhaust ports, we have to ensure that smoke flow velocity uniformity of smoke exhaust gas outlet when exhaust. That helps tunnel gas in a stratified state and personnel and vehicles to escape as soon as possible. As the opening angle of the flue gas valve and the effective air area of the exhaust gas outlet are the corresponding, through physical experiments and numerical simulation experiments we research on the optimal opening angle of the smoke outlet in each group and confirm best exhaust valve setting scheme.3) Analysis of opening group number of smoke exhaust port. The key to smoke control is to develop a reasonable ventilation and smoke control scheme. The key of the smoke control is the number and the angle of the smoke opening group. Through numerical simulation experiment, analysis of the effect of the smoke extraction when the unilateral or axial flow fan is opened. Put forward Reasonable open group number of smoke exhaust port under fire condition.4) Put forward immersed tunnel smoke smoke control strategy under fire conditions.Using FDS software, establish 1:1 tunnel fire model. Study that when the immersed tunnel in different slope fire, should adopt what kind of organization mode of smoke(two-way equalization of smoke, the downstream side of the one-way smoke, the upper end of the one-way exhaust gas) and how to take the exhaust port open plan(upstream open 1 groups + downstream open 4 groups, upstream open 2 + downstream open the 3 group) in order to carry out the tunnel fire smoke control and the personnel safe evacuation to provide the support.