The Study Of Calculation Method On Dynamic Response Of Soil Induced By Moving Loads

With the development of track traffic and the increase of train speed in China, people have began to give more and more concern to the influence of vibration induced by traffic load to around environment. Therefore, in order to evaluate the environmental vibration along railway lines, it has very important practical value to analyze and calculate the dynamic response of soil under moving load.Understanding the mechanism of vibration generation and its propagation rule is the prerequisite to evaluate environmental vibration correctly and appropriately. Generally, track structure consists of track, rail pad, sleeper and ballast. When train running on the track, there has interaction between wheels and track, and the track will bend because of the weight of wheels. Then, the bending waves will propagate to soil and around areas through the component of track structure, which can cause the second vibration on buildings. Based on above analyses, the main ideas of this paper can be summarized as follows:1 The displacement of soil under moving load can be calculated using multi -layer method, then the velocity and acceleration can be deduced and spectrum can be analyzed. Though this working condition can not exit in practice, it still has its values: first, it reduced calculation and obtained approximate solution; second, the results can be compared with the results obtained in chapter 3, which have considered the effect of track. This comparison can be used to analyze the effect of track to the dynamic response of soil; last, it is the basis of chapter three.2 Based on chapter two and considered the coupled effect of track and soil, the dynamic response of soil under moving load with different soil models, track models and load models have been calculated respectively. The effects of different parameters to the dynamic response of soil have been compared and analyzed: first, as to soil models, the depth of soil, the elastic half - space foundation model and rigid foundation model have been considered; second, as to track models, one -layer beam model and two -layer beam model have been discussed; third, as to load model, single concentrated point load model, SDOF concentrated load model and two -DOF system have been compared. Through these comparison and analyses, some useful proposals have been suggested, which have much practical significance to evaluate the effect of vibration induced by track system to around environment.