Experimental Study On Smoke Flow Feature In Eight-lane Immersed Tunnel

As an important part of the traffic route,the highway tunnel is developing towards the mountains and the offshore sea.With the increase of highway tunnel scale,tunnel operation management is facing great challenges.Especially for an eight-lane ultra wide section immersed tube tunnel,operation ventilation and smoke extraction solution is the important factors that affect or restrict the overall construction scheme,it is also an important measures during the operation of fire safety.Relying on the shenzhen to zhongshan river-crossing tunnel project,this paper surrounding wall exhaust mode and transverse contact way at the bottom of the lateral and smoke exhaust,with different fire source position and different smoke exhaust port distance of fire smoke flow study.In this paper,a large scale model fire test is carried out based on the results of numerical simulation test.Through the study on the temperature diffusion range of flue gas,the spread range of flue gas and the height of flue gas layer,it is concluded that the eight-lane special pipe tunnel is reasonable and the smoke path is set apart.The research contents are as follows:1)Based on the actual structure design of the deep channel,a numerical simulation model is established.Access to specification and combining previous research results,set a reasonable numerical simulation test parameters and measuring point,research and analysis a large amount of test conditions,late for the parameter and working condition of the physical model test set to provide the reference.2)In the engineering background of pressure-pad-force channel,according to the practical design of tunnel,establish 1:15 large scale test tunnel,and equipped with perfect mechanical and electrical system and measurement system,created an eight-lane specialty immersed tube tunnel comprehensive experimental platform.3)A large scale model test was carried out for the lateral wall smoke removal method and the lateral connection of the flue and the bottom exhaust.In case of fire smoke flow as the research object,and concluded three different positions of fire smoke extraction mode when the spread of the scope of the spread of the flue gas temperature,flue gas range and a decline in flue gas layer parameters such as height.It provides a basis for the selection of smoke extraction mode in the tunnel fire of ultra-wide section immersed tube.4)To study the spacing of reasonable flue in the way of horizontal contact flue smoke exhaust.According to the results of the numerical simulation test,four different flue gaps were set up,and the smoke flow characteristics were obtained through the experiment of large scale physical model.It is of important reference value for the design of the spacing design of smoke vent in the tunnel exhaust system of deep channel immersed tube.