Research On Key Technology Of Environment Vibration And Noise Caused By Viaduct Rail Traffic

The fast construction of high-speed railway and urban rail transit accelerates the economic development effectively, but it also makes the environmental vibration and noise problems more and more obvious, which affects people’s daily life and work seriously. Elevated rail tarnsit plays an important part in the railway system, and the control of its vibration and noise impact on the surrounding environment is urgent and imperative.In this paper, the main line is the environmental vibration and noise reduction of the viaduct rail traffic. The full text concentrates on three key aspects of environmental vibration and noise technologies, namely the theoretical prediction, control measures and evaluation management, which are complementary to each other.Firstly, based on the vehicle-track coupling dynamics theory, a time-history analytical model for predicting environment vibration casued by train running on the viaduct is given in this dissertation. In this model, the entire system of the coupled model is divided into two subsystems, one of which consists of the vehicle subsystem, rail subsystem, bridges-pile subsystem, and the other is the environmental soil subsystem. And then, using the MATLAB language, a predicton and analysis system of environment vibration-VTBS-1 is developed. Compared with the test data, this model is proved to be effective. Measured datas combined with the calculated results from VTBS-1 are purified to study the characteristics of the environment vibration caused by elevated rail transit.Secondly, a silent rail with slotted-off layer and a cross-legged silent rail which were used to reduce wheel-rail noise have been designed based on the damping techniques and optimization theory. The suitable material and structure parameters of them have been found from extensive numerical tests and then the prototypes of them were made and tested in laboratory. Results are very promising. As for the silent rail with slotted-off layer, the reduction of the acoustic radiation pressure level of rail noise by vertical excitation and lateral excitations are 8.2 dB and 9.4 dB respectively, and as for the cross-legged silent rail, the reduction of the acoustic radiation pressure level of rail noise by vertical excitation and lateral excitations are 10.4 dB and 13.2 dBrespectively.Thirdly, with broad vibration absorption frequency and easy installation and removal, a waveguide vibration absorber which is served to control the vibration of the CRTSII slab has been designed based on the waveguide vibration absorption theory. Its suitable material parameters and installation method have been found based on multi-scale optimization. The performances of the slab with and without the optimal waveguide vibration absorber have been compared according to vibration power flow. Results are very excellent that waveguide vibration absorber can effectively absorb and dissipate the vibration energy in the slab and from the slab to the baseplate in the frequence of 0～1000Hz.Finally, a new noise map has been proposed as an evaluation and management method to evaluate the environment noise caused by viaduct rail traffic. The calculation of the new noise map based on the following three steps. The first step is to caculate the source noise by vehicle-track-bridge-pile and soil coupling model and the empirical method. The second step is to calculate large area noise problems using Cadna/A software by revising sound guidance prediction mode according to the German schal103 mode. The last step is to compute the two and three-dimensional noise map combined with GIS technology. To make it easy to understand, taking the Shenzhen Metro Line 6 for an example, a detailed explanation of the calculation procedure and how to use the map to assess noise vibration have been given. Meanwhile, the superiority of the noise map as an evaluation management method for the environment noise caused by viaduct rail traffic has been showed.