Study On Vibration Isolation Dyke Based On Railway Environmental Vibration

High-speed railway has the advantages of high speed,low pollution,low energy consumption,strong passenger transport capacity,good safety performance,high comfort,allweather operation,less land occupation and good social benefits.Therefore,high-speed railway is the theme of China's current transportation development.On July 13,2016,the latest revised “Medium and Long-Term Railway Network Plan” document was issued.From this document,it can be seen that the coverage area of China's railway lines will increase greatly in the future,and the high-speed railway network will be more perfect.According to the report of Premier Li Keqiang during the two sessions,the national high-speed rail operating mileage has exceeded 29,800 kilometers,an increase of nearly 42 times compared with 2008.However,with the increasing scale of high-speed railway networks,the problem of high-speed railway environmental vibration is becoming increasingly prominent.The high-speed railway environmental vibration has the characteristics of long-term existence and recurrence,which will cause great trouble to the production and life along the railway.In this context,this paper proposes a way to reduce the high-speed railway environmental vibration-vibration isolation dyke.By assuming that the track and the vibration isolation dyke are infinitely long along the track,the problem is simplified to a plane strain problem,and a two-dimensional finite element model of embankment-soil-vibration isolation dyke is established for qualitative analysis.Based on the experimental data,the correctness of the method of modeling is proved.After a brief analysis of the damping principle of the vibration isolation dyke,the two-dimensional finite element model of the embankment-soil-vibration isolation dyke is used to verify the damping effect of the vibration isolation dike,and then the parameters which have an impact on the damping effect of the vibration isolation dyke are analyzed.These parameters include the material of the vibration isolation dyke,the slope angle of the vibration isolation dyke,the size of the vibration isolation dyke,the train speed,the distance from the track center and the site condition.In addition,according to the damping principle of the vibration isolation dyke,a special form of vibration isolation dyke is proposed,and the damping effect of the special form of vibration isolation dyke is analyzed.In order to study the influence of the number of rows of the vibration isolation dyke on the damping effect,a two-dimensional embankment-soil-vibration isolation dyke model with different rows of the vibration isolation dyke was established and analyzed.The results show that the vertical vibration at the two foot of the vibration isolation dyke will be amplified,but not at the top of the vibration isolation dyke;the vertical vibration response of the surface is weakened in the range of at least 20 m after the vibration isolation dyke,and the vertical vibration level can be reduced by at least several decibels;the vibration isolation dyke with greater elastic modulus and bottom width has better damping effect;the damping effect of the vibration isolation dyke is better when the distance between the vibration isolation dyke and the center of the track is smaller,the train speed is higher,and the first layer of the soil is softer;increasing the degree of the slope angle of the vibration isolation dyke within a certain range will enhance the damping effect;increasing the height of the vibration isolation dyke has little effect on the damping effect;the inner hollow of the vibration isolation dyke has no effect on the damping effect,which means that the quality of the vibration isolation dyke has little effect on the damping effect;the number of corners of the vibration isolation dyke does have an effect on the damping effect;in the non-vibration amplification area,as the steps of vibration isolation dyke increase,the damping effect of the vibration isolation dyke becomes better and better;however,in the vibration amplification area,as the steps increase,the damping effect of the vibration isolation dyke is getting worse;increasing the rows of the vibration isolation dykes can improve the damping effect,but when the rows of the vibration isolation dykes increase to a certain number,the damping effect hardly increases.