Theoretical Research And Numerical Analysis Of The Open Trench For Vibration Caused By Moving Train

Along with the operating speed increases of the train, the vibration and noise of the surrounding environment caused by moving train become more and more serious, which have attracted extensive attention. The ground vibration generated by trains spreads around in the form of wave. The influence of the vibration on the physical and mental health of residents around the railway, work and life quality, structural safety of the neighboring constructions and the normal performance of precise instruments and high-tech facilities have been immeasurable. Therefore it is very meaningful and of applied value to analyze the environment vibration caused by the moving high-speed train as well as the way how to reduce the vibration effect.Previous studies have indicated that when the speed of the train reaches the Rayleigh wave velocity of the ground surface, the vibration would be enlarged. Compared with bulk wave, the Rayleigh wave attenuation gradient is not obvious. In influential range of the building vibration induced by moving train, bulk wave tends to get larger attenuation and the undiminished Rayleigh wave still accounts for a large proportion. Therefore, it is necessary to set the vibration isolation measures in the propagation path, from the perspective of propagation and attenuation, to study its isolating vibration effect on the train operation. It is generally considered that the open trench isolation was an effective way to shield the ground vibration in the propagation path.In this paper, theoretical analysis and numerical calculation methods were used in combination. With theoretical analysis carried out on the propagation of Rayleigh wave in case of the open trench vibration isolation and numerical simulation of the vibration isolation effect of the train operation in the condition of open trench, the calculation results were drew and compared. The main contents include:(1) Based on theoretical analysis, the law of Rayleigh wave among the open trench and the variation of Rayleigh wave with distance was derived under the condition of the open trench. The relationship between Rayleigh wave attenuation and the parameters of the open trench was obtained.(2) The model of train-rail-soil-open trench system, including the train-rail model and the soil-open trench model, has been established. And several relevant situations for the model were discussed.(3) The track dynamic forces calculated by the train-rail model were applied as the excited loads on the model of the soil-open trench system. Considering the open trench parameters, including depth、width and the relationship between source and its position, and types and speed of the vehicle, numerical analysis was carried out on the variation law of soil vibration caused by train. And results from theoretical analysis and numerical calculation were compared, coming up with some summarized rules.