Research on Optimal Gradation of Ballast Track on Bridges Based on Quasi-dynamic Evaluation
Ballast gradation,an important parameter of ballast track,has a great impact on the quasi-dynamic stability and bulk density of ballasted beds on bridges.In this paper,a model of the ballasted bed on bridge was established using the discrete element method to study the difference of quasi-dynamic stability of ballasted beds under different gradation levels in different countries.Based on the limit thinking method,the influence of each size content on the quasi-dynamic stability of ballasted beds on bridges was revealed and the bulk density characteristics of ballasted beds were preliminari-ly explored.The results show that when the density of ballasted bed on the bridge is 1.7 g/cm3,the lateral resistance of ballasted bed is in the order of Russian Class B＞Chinese special-grade＞Chinese first-grade＞American 4A.The high-er the content of large-sized ballast,the greater the lateral resistance of ballasted bed.As the content of small-sized bal-last increases,the lateral resistance of ballasted bed decreases first before increasing slightly.In order to ensure high stability of the ballasted bed,the content of small-sized ballast is suggested to be greater than 0 but not more than 30％,while the content of middle-sized ballast should not be 0 and the content of large-sized ballast should not be less than 15.5％.The ballasted bed on the bridge built in the optimal gradation section has the bulk density characteristics of the ballasted bed,which is favored by the project.
ballast trackstability of ballasted bedoptimal gradationdiscrete element methodlateral resistance
万方数据
维普
