Analyses And Controls Of Train-Induced Structure Vibrations

With the development of social economy in our country, our country is entering the high-speed train era. The orientation of railage has turn to high-speed,weighty-load,great-transport capacity and huge-density. Lay aboard cities, there are more and more railway lines inevitably come cross or come close to the center of the city. The appearance probability of passed trains has been to high frequency. In other respects, along with the amount of population's steady increase, traffic jam question become more and more serious. At this time, Urban rail transport, due to its speed,punctual,capacity and safety, has become a primary choice to ease the heavy traffic jam question and the prime importance work of traffic development in large cities. All those ingredients result in the addition of transportation density.On the other hand, with the development of urbanization, there are more and more high-buildings appearing in the city. It inevitably lead many structures built in or close to the intense vibration-sensitive areas beside the railway. Furthermore, with the development of timbering and technology, there are more and more lightweight but high-strength materials adopted by all kinds of engineering which lead railway surroundings and buildings affected by rail transportations easily because of the reduction of structures'damp and inherent frequency. Consequently study the influence and control-measure of train-induced building vibrations will be very available for avoid and mitigate the environment vibrations problem.Based on the above analysis, the thesis has made some study on the following respects:1. Combining with the environment vibration test to the No.4 building in Xiangyi-residential district and analyzing train-induced structure vibrations'characteristics,transmit rules and intensity distribution;2. Using the mathematical calculative software——MATLAB, a three-layer beam plane model of track is established of which the dynamical responses are solved under the train's moving load condition, and the impact of speed on railway structure dynamical responses are also analyzed with the Fourier Change Method;3. Using the finite element software——ANSYS,the ground-building interaction 3Dimension model is established and the dynamical responses of building under the train's moving load are analyzed. The computed result is compared with the test data. The influence of the speed of the train,axial load,distances to the central of the railway and the form of the building to train-induced building vibrations has also been studied. Analyzing the factors affect the vertical and horizontal vibration;4. Using the finite element software——ANSYS, the ground-building interaction 3Dimension model with barrier is also established. The vibration isolation principles of barrier trenches are analyzed in three-dimension space with Transient Dynamical Method. The influence of the trench depth, length, distances to the building and in-filled materials of isolation trenches on isolation effect has also been studied;5. Introducing the environmental vibration's harm to people. the environmental vibration evaluation standard in different country were reviewed, especially in the vibration evaluation standard to human beings'health. On this precondition, the China Standard of Environments Vibration in City Area has been researched, some problems of which has also been point out afterward to proposal many suggestions for consummating China's environmental vibration evaluation standard.Through above tasks, the results point out that:1. Higher train speed induces the top of roadbed's loads and the vibrations'primary frequenies become larger basically;2. The structural vibrations are of low-frequency characteristic and the structures have attenuating functions to the high-frequency vibrations;3. The structural vibrations show zigzag tendencies with an increase in floor elevation, compared to other two directions, the vertical vibration is most important and the numerical value of it is also most;4. Higher train speed, lengthen the length of the train, heavier load and shorten the distance between the building and the track all induce larger structural vibrations;5. The frame type of the structures has better restraint-capability to the train-induced vibrations than the shear-wall type has;6. The changes of trench depth, the trench length, the distance from the trench to the building and the in-filled materials have sharp influence on the vibration isolation effect.7. Compared to other countries'vibration bound standards, China's entironment vibration standard is more strictly and hardly manifest the stochastic characteristic of the vibrations.