Research On Vibration Transfer Characteristics And Dynamic Response Of Typical Tracks On Urban Rail Transit Viaduct Lines

ABSTRACT:The total noise produced by track structure system on viaduct is mainly composed of radiated noise of bridge and track structure, and track structure noise includes radiated noise of wheel-rail system and track slab. China has adopted more and more measures in reducing the vibration and secondary radiation noise of urban rail transit of viaduct, and measures taken in under-rail, under-sleeper and under-track mainly aimed at reducing viaduct secondary radiation noise. However, in practical engineering applications, some measurements increased track structure noise which resulted in increasing the total noise of viaduct, even with some rail corrugation diseases. Therefore it is particularly necessary to study on the vibration transfer law of each part on viaduct lines.Combined with vibration transfer characteristics and vehicle-track-bridge coupling dynamic theory, this paper established three mechanical model of classic track on viaduct using the finite element method, the vibration transmissibility and dynamic response of vehicle-track system is studied. The result shows:(1) With reducing the vibration of bridge, the egg fastener track and rubber pad floating slab track will simultaneously increase rail vibration in most frequency range, and the former one has little effect on reducing secondary bridge radiated noise, so egg fastener track should be carefully designed or the egg fastener track need to be discreetly used on viaduct lines.(2) The predict results obtained may differ from the actual deviation while only one type of rail irregularity is used in analysis, which is not comprehensive enough.(3) The maximum vertical vibration acceleration values of rail, track slab and bridge are in linear relationship with wave depth of irregularity roughly.(4) The main frequency and severity of vibration caused by train are related with the wavelength of irregularity and velocity of train. Measures should be taken in controlling the sensitive wavelength responding to each bridge design velocity.(5) Increase bridge-girder cavities (double cavities, three cavities) can reduce the vibration of rail and slab, and at the same time reduce the vibration of bridge at some frequencies, it also has a certain effect on controlling the radiation noise of bridge.