Study On Aerodynamic Effects Of Intercity Railway Tunnel And Underground Stations

When intercity trains enter the tunnel with a high speed, there will have violent pressure fluctuations inside the tunnel, and generate obviously aerodynamic problems, and produce the large aerodynamic pressure on accessory structure of the tunnel, such as protective doors of caverns in tunnel, platform screen door, concrete structures of exhaust duct in top of the track, and affect their structural stability.This paper relies on an intercity railway tunnel and uses the CFD numerical simulation method to simulate and analysis the pressure field distribution when the train is going through the tunnel and underground stations. By respectively simulating a single train going through the tunnel, trains passing each other at tunnel and underground stations, distribution of pressure field and maximum pressure value on accessory structure in tunnel and underground stations under various conditions have been obtained. It provides a reference for the subsequent design and traffic organization.Through the above analysis, a systems analysis on distribution of pressure field in tunnel and underground stations has been made. The following conclusion can be concluded:(1) When a single car is going through the tunnel, the peak pressure of measuring points in the tunnel entrance increase with the train entered the tunnel length increasing until the train totally enters tunnel. Abrupt changes in the cross-sectional area of a tunnel make the pressure wave in tunnel very complicate. Abrupt changes in the cross-sectional area of a tunnel、reflection、refraction and superposition of the pressure wave make the maximum positive pressure of measuring points decrease with increasing distance from the tunnel entrance.(2) When trains are passing each other at tunnel and underground stations, the maximum pressure in tunnel and underground stations is the result of train crossing pressure wave, the initial compression wave and initial expansion wave. The time when the maximum pressure turns up is not the fixed, it must be considered comprehensively.When two trains are passing each other, the maximum pressure where trains passing each other is twice than a single car crossing.(3) The pressure in tunnel and underground station increases with the velocity of trains. When the velocity of train is250km/h, the maximum pressure in protective doors of cavern in tunnel, screen door and concrete structures of exhaust air-duct in top of the track in platform of main line and arrival-departure track are2700Pa,3200Pa,3200Pa,1500Pa,1500Pa.