Research On Reasonable Ventilation Parameters And Safety Evacuation Mode Of Super Long Highway Tunnel

In recent years,with the construction of super-extra-long highway tunnels in China entering a peak period,super-extra-long highway tunnels will play an important role in the future development of the national economy.Due to the long distance and large traffic volume of super long highway tunnel,reasonable ventilation facilities configuration is the key to ensure the air quality in the tunnel during operation.At the same time,the fire in the tunnel is extremely harmful.Once a fire occurs in the tunnel,it is very likely to cause major safety accidents and economic losses.In order to ensure the efficiency and safety of super long highway tunnel during operation,this paper studies the ventilation mode of super long highway tunnel operation.The selection of operating ventilation parameters of super-long highway tunnels,the smoke diffusion characteristics and temperature distribution under fire conditions,and the safety of fire evacuation were studied.The main research contents and results are as follows:(1)By using the method of literature research,the current operation ventilation mode and auxiliary channel setting of super-long highway tunnels are investigated.The selection of ventilation mode and auxiliary channel of super-long highway tunnels is analyzed and summarized,and the main ventilation mode and adaptability of super-long highway tunnels are clarified.(2)Based on the general situation of Yunshan tunnel project in Shanxi Province,according to the advantages and disadvantages of the ventilation mode of the super-long highway tunnel and the geological conditions of the tunnel,two ventilation schemes based on the inclined shaft longitudinal ventilation mode are designed for Yunshan tunnel.The ventilation network diagram method is used to analyze the two ventilation schemes,and the design air volume,wind pressure,jet fan number and other related ventilation parameters of the ventilation scheme are studied.On the basis of the optimal ventilation scheme,considering the different locations of tunnel fire and fire power,the factors affecting the ventilation parameters are analyzed.(3)Based on FDS fire dynamics simulation software,a three-dimensional numerical model of typical ventilation and smoke exhaust section of super-long highway tunnel was established to study the smoke and temperature changes caused by fire under different ventilation and smoke exhaust sections and different traffic congestion conditions,and the smoke diffusion characteristics and temperature field distribution at different combustion stages of tunnel fire were obtained.(4)According to the smoke diffusion characteristics and temperature field distribution of the fire in super-long highway tunnels,the available safe evacuation time and the required safe evacuation time of personnel evacuation were studied according to the gender-age composition ratio of personnel in the fire tunnel,different evacuation speeds,and the crosschannel spacing of the tunnel,and the evacuation safety of tunnel fire personnel was evaluated.This paper aims at the above four points of research on ventilation and disaster prevention of super long highway tunnel,provides reference for ventilation setting of the same type of tunnel engineering and evacuation after fire,and has certain value for improving the operation safety of super long highway tunnel.