Study On Train-induced Vibration Of Semi-closed Noise Barrier On The Urban Rail Transit Viaduct

Urban rail transit brings convenience to people's travel,but also causes serious noise pollution,while noise barriers are widely used as an effective measure to prevent traffic noise.With the widespread application of noise barrier in the rail transit,the problem of vibration damage is gradually exposed,and it is imperative to carry out relevant research on its structural vibration.All of the current researches on structural vibration of noise barrier almost focus on the background of high-speed rail traffic,and the influence of fluctuating wind load induced by traveling train is mainly considered.While the urban rail transit always operating at a low speed of train,rail force of train usually contributes more as a factor exciting noise barrier of urban rail transit viaduct,especially for noise barrier on the horizontal curved viaduct,which is prone to bend and twist coupling vibration under the excitation of wheel-rail force.Therefore,it is of great significance to get a basic understanding of the vibration regularities of the urban viaduct noise barrier.Based on the background of noise barrier vibration in urban rail transit,researches about the train-induced vibration of noise barrier in urban rail transit has been carried out combining field measurement and numerical simulation,and the main work in this paper is as follow:(1)Field measurements about the train-induced vibration of semi-closed noise barrier on both straight viaduct and curved viaduct have been carried out.Then,based on the test data,dynamic characteristics of the viaduct and noise barrier,excitation characteristics of subway train across the viaduct,and primary features of vibration responses of semi-closed noise barrier generated by the passing train has been discussed.(2)A parameterized finite element model of semi-closed noise barrier and viaduct has been established via ANSYS Parametric Design Language(APDL),and the validity of finite element model has been verified comparing with the measured structure mode.A program for solving the spatial coupling vibration of train-viaduct-noise barrier has been accomplished combining APDL with MATLAB code,which applicable for solving vibration responses of any type of noise barrier under the exciting of vehicle-bridge interaction;Then verification the program with a classical example and the test data has been conducted,and it proves that the program is practicable for the subsequent work of parametric analysis.(3)A lot of numerical simulations have been performed to investigate the fundamental regularities of train-induced vibration of the semi-closed barrier,as well as the influences of the driving direction,train formation,curvature and span of viaduct-noise barrier to the vibration characteristics of the semi-closed noise barrier.And several conclusions have been obtained,they may be referable for practical engineering or the further research.