Research Onenvironmental Vibration Induced By Trains On Embankments Of Cheng-Guan Rapid Railway

Currently, high-speed railway has become the main transportation. As a kind of transportation with the fast speed, time accurate, safe, comfortable, it is well adapted to the need of modern social and economic development. The rapid development of high-speed railway has brought environmental problems which be ignored any more, especially the environmental vibration problem which caused by high-speed trains. The ground vibration caused by the high speed rail train is mainly in the embankment section and bridge section. When it amplitudes at the same distance from the railway, the vibration from embankment section is larger than bridge section. So studying the characteristic of embankment vibration has great significance. Based on the existed studies of domestic and international rail transportation system vibration, this thesis combined the field test data of vibration induced by the Cheng-guan high-speed railway and analyze the ground vibration characteristics of Cheng-guan high-speed railway embankment section.This paper measured the vibration data of Cheng-guan K24+280 embankment, then summarized the characteristics of embankment ground vibration response by analyzing the time-acceleration curve and spectrum-acceleration curve, and calculating the peak factor of vibration. This thesis fitted the Z vibration level data to obtain empirical formula of environmental vibration attenuation. Through this research, there’s the conclusions:the ground vibrations caused by trains attenuated with the increasing distance overall. The measuring points close to vibration source decay faster. Some distance occurred the vibration amplification phenomenon. By analyzing crest factor of measuring point, we found that it was generally effective to evaluate the train vibration of the Cheng-guan line by the basic evaluation method, there’s no need to use other evaluation methods. The measuring points closed to vibration source are mainly affected by high frequency vibration. With the increase of the vibration transmission distance, the impact of the high frequency vibration on the measuring point decreases. The main frequency near the vibration source is the inherent vibration frequency induced by passed trains. When the distance exceeds a certain limit, the train inherent vibration frequency decreases, the vibration to vibrate the ground-based, ground-vibration takes the dominant position. The low-frequency vibration affects a wider range. In the study of vibration damping speed, the vibration spectrum can be divided into three bands, the low-frequency band 1～20Hz, the intermediate frequency band 20～50Hz and the high-frequency band 50～125Hz. The low-frequency energy is the least over the entire range of vibration, with the distance increasing, the speed of low-frequency vibration attenuation is slow. This band shows rebound phenomenon regularly. High frequency vibration has the maximum energy in the whole range of the vibration. The rate of vibration attenuation in this band is fastest, and it rarely appears the vibration rebound phenomenon.