Study On Environment Control Technology Of High Altitude And Low Grade Highway Tunnel

The trend of China’s terrain is high in the west and low in the east and it can be divided into three steps.With the development of China’s transportation industry,China’s highway network has gradually extended to the western mountainous.Therefore,a large number of high-altitude highway tunnels have emerged what followed by a series of operating ventilation problems.The safety and comfort standard of high-altitude highway tunnel under low-oxygen and low-pressure air environment,traffic wind under high altitude traffic situation,and the efficiency of fan under high-altitude and low-pressure are particularly prominent in tunnel operation and ventilation.In order to solve the above problems encountered during the operation ventilation of highaltitude and low-grade highway tunnel,the control standard of CO concentration,the control standard of Ⅵ concentration,the control standard of air exchange frequency,and the influence of traffic vehicles on the tunnel air flow field and the step-up efficiency and longitudinal working length of the jet fan under low-pressure environment are systematically studied.The operational ventilation control technology of high-altitude and low-grade highway tunnels has been established.The main research work and achievements of this thesis are as follows:1.The effect of altitude on CO toxicity and the time of human reaction is analyzed.The altitude-corrected CO concentration limit,the control standard of Ⅵ concentration by considering different altitude and vehicle speed and the critical condition and control standard of ventilation for natural wind and traffic wind are put forward in this paper.2.The influence of traffic vehicles on the tunnel air flow field when the cars passing through the tunnel is simulated by using CFD dynamic mesh,the kinetic energy of the vehicle transfer to the air is found to be gradually dissipated in the form of swirl in both lateral and longitudinal of tunnel,and the influence scope of vehicles on the tunnel air is analyzed.3.The step-up efficiency of the jet fan and the frictional resistant coefficient of the longitudinal ventilation along the altitude is determined.The influence of the longitudinal distance between different fans on the length of the longitudinal working section of the rear fan is analyzed.Through the study of the operation ventilation control technology of high-altitude highway tunnel,it provides the basis for the ventilation design of high-altitude highway tunnel operation and make the ventilation system of the highway tunnel works normally and avoids the waste of energy while ensuring the safety of people.In line with the people-oriented principle,it provides a safe and reliable environment-friendly technical support and reference for other similar high-altitude highway tunnels.