Study On Ventilation Technology Of The Operation And Fire Rescue In Large Underground Interchange

With the rapid development of urban traffic in our country, the ground traffic pressure is increasing, and large underground interchange as the extension and supplement of ground road, is being widely used as it has the advantages of short construction period, easy cohesion with the existing ground transportation system, centralized treatment of pollutants and conducive to city environment. For underground interchange tunnel, as it is composed of a number of tunnels, the distribution of air pollution in different tunnels, air flow organization and so on are required effective control. Whether to solve the problem of operational ventilation and fire ventilation is one of the control factors of the successful construction and operation of the tunnel.This paper relys on the Shenzhen transit highway connecting line project, and it adopts the methods of theory analysis, network analysis and numerical simulation to study the operation ventilation and rescue ventilation of large underground interchange. The main research works of this thesis is:(1)Obtaining the air demand that based on the project of tunnel sections by means of traffic volume, according to the area of the tunnel and the air demand to analysis the pollutant discharge pattern, the silo location selection and the airflow organization. The operation of the air flow is studied by using the technology of ventilation network, The fan arrangement is obtained according to the most unfavorable driving condition. The inverse calculation is took for the air flow organization of each driving speed in the tunnel, in case the scheme of fan is reasonable.(2)Using CFD three-dimensional numerical simulation software FLUENT to simulate and analysis the pressure rise characteristic of jet fan in the large section (three lane and four lane section) of urban underground interchange, it is concluded that the reduction coefficient of the jet fan is 0.76, and the transverse installation distance of jet fan section is 2.5m.(3)Putting forward different schemes of disaster prevention and rescue ventilation according to each section of underground interchange tunnel import and export, underground intersection position, shaft position, and the set of cross channel dealers. At the same time, using the fire dynamics software FDS to simulate the interchange tunnel critical wind speed, the fork control wind speed and cross channel control wind speed.(4)The ventilation network technology is used to study the rescue ventilation of large underground interchange, and the fan configuration of underground interchange is obtained according to different fire position. The FDS is used to simulate and analyze the effect of smoke exhaust in underground interchange, so the fan configuration and rescue plan are verified.