Studies On The Mechanical Behavior Of Railway Ballast With Sand

Most of railway line is the ballasted track structure in China. In the ballasted track structure, the ballast layer is the most important component of the railway track infrastructure. It is subjected to both the traffic load and the exposure of environment changes, therefore the ballast bed deforms and degrades highly affecting the performance of the railway track. In wind-blown sand areas, the infiltration of fine sands has great effects on the elastic modulus and cumulative settlement of ballasts. It induces the loss of resiliency of ballasts. Now there is no systematic research on the sand affect the mechanical behavior of ballasts in our country, therefore by studying the elastic and cumulative settlement of ballasts under different sands content, this article is helpful for people to understand the mechanical behavior of the ballasts with sand, meanwhile, has an important engineering significance.This article combines the mechanical tests and discrete element method numerical simulation, the macro and micro mechanical behavior of ballasts with sand are analyzed. The present work can be summarized as followed:1.The single ballast particle strength is calculated by the method of radial crushing test, and the ballasts'strength of a certain size range is estimated based on weibull statistical theory of fracture.2.Quasi-static loading test equipment and programs are designed, meanwhile, the modulus of ballasts under different sand content are studied. What's more, using the DEM simulate the test process has obtained the micro mechanical information, such as contact force, coordinate number and chain distribution.3.The cumulate settlements curve of ballasts under different sand content are determined by ballast box tests, the cumulative settlements are exponential fitting, the fitting results are good.