On The Study Of Effect Of Designed Parameters Of High-speed Railway Tunnels On Aerodynamic Effect Of Vehicle-tunnel Coupling

With the rapid development of China’s economy in recent years, the construction of high-speed railways between different districts, especially large cities, is increasing quickly day by day, though not enough.There are quite a lot of difficult problems on different aspects of technology of high speed railyway in order to improve it and transfer it to the world. And one of the most crucial and worthy ones is on the study of the aerodynamic phenomena caused by a train entering a tunnel.This paper is based on "The research about the aerodynamic load spectrum of tunnel and the matching relations between train/ line/ tunnel/ aerodynamic under different grades of speed" project of CHINA RAILWAY company. In the paper, the effect of designed parameters of high-speed railway tunnels on aerodynamic effect of vehicle-tunnel coupling was studied. The specific work and conclusions are as follows:(1) Researching the minimum clearance area of tunnel for passenger comfort in railway tunnels.The distribution and propagation of transient pressure in tunnel are analyzed, as same as the train sealing index and the transmission of air pressure between the inside and outside of train; the standards about passenger comfort from many countries are finished; For the comfort and the sealing technology level at present, the minimum clearance area of a 1000m tunnel should not be less than 107m2, when train runs through it at 400km/h.(2) The research about pressure variation law of aerodynamic effect in the variable cross-section tunnels.Take two types (including horn-type and step-type) of variable cross-section tunnel into account. Adjust the design parameters of tunnel, including the expansion rate of entrance, the clearance area of tunnel, the length of variable section and other variables,to analyse the law of influence on the aerodynamic effects under various conditions.With the requirement of comprehensive construction cost and aerodynamic load reduction, an optimal design scheme of variable cross-section tunnel with length 1000m is obtained.(3) By comparing with the pressure distributions of the variable cross-section tunnel and the common tunnel, the impact of the design of the variable cross-section tunnel to relieve aerodynamic effect is analyzed.