Study On Track Upon Vibration-noise Controls In Viaduct Rail Transit System

The urban rail transit of our country has entered into a climax construction stage. Urban rail transit system , which has brought us with great convenience, also causes many problems such as vibration and noise inevitably. The vibration and noise in urban rail transit system are drawing more and more attention in recent years. This thesis describes some means and measures of tracks controlling vibration and noise in the viaduct rail transit system. Emphasis is laid on elastic fastener and floating slab track . This thesis does systematic study of dynamic traits of track, reduction property of track , dynamic response of bridge system and vibration influence on environment by research methods of combination of several means , such as field test, theory analysis and finite element numerical analysis.This thesis researches on the vertically vibration of vehicle-track-bridge environment, makes use of vehicle dynamics, track dynamics, bridge dynamics, mode analysis theory, track-bridge dynamic finite element method and other based theories. takes vehicle, track, bridge environment as a whole vibration system connected by wheel-track relationship and track-bridge relationship. Dynamic traits of different track and different bridge and bridge on different support, the property of vibration-noise controls of system, dynamic response of bridge system and vibration influence on environment are on target.In this thesis, a four-axle rolling dynamic model of metro vehicle is accepted, rails are modeled as Euler beams laid on elasticity supports, slabs are modeled as rectangle plates laid on elastic foundation, sleepers, blocks and discrete ballast blocks are modeled as rigid bodies. Meanwhile, based on the Hamilton principle of the discrete dynamical system, not only establish the dynamic equations of the track-bridge, and get out the results of dynamic equation when the support condition is simple beam.In order to investigate vibration influence of bridge, track and the whole system, it is necessary to analyze the self vibration identity of track and bridge. Based on an analysis soft ANSYS, vibration frequency and mode shape of different track structures and bridges are analyzed, a coupling dynamic finite element model of track-bridge system is set up. Then, acceleration of bridge is acquired. Methods of reduce track noise are discussed. Field tests of vibration response of metro lines in different track structures are carried on to be compared with the results of analysis.