Large-Scale Box Tests of Ballast Layer with Varying Degrees of Coal Dust Contamination of Crushed Stone

Objective: to investigate the process of accumulation of residual deformations in a ballast prism with different levels of contamination with coal dust, followed by determination the ballast service life. Methods: the achievement of the research objective was carried out through large-scale box tests of ballast layer. Cyclic load, simulating the impact of heavy freight train, was transmitted on the ballast layer through reinforced-concrete half-sleeper with rail (R65) installed on it. During the tests, the residual settlement of half-sleeper was recorded as a function of the number of applied load cycles. Results: the results of conducted studies showed that increasing the level of crushed stone contamination with coal dust in wet state is accompanied by more intensive growth of residual deformations in the ballast layer. Practical importance: the results of the study make it possible to evaluate the impact of coal dust contamination of crushed stone on the intensity of accumulation of residual deformations of the track, which makes it possible to solve the problem of determining the service life of ballast layer.