Experiment on the performance of high-speed railway subgrade with tire debris mixed filling

As an important component of railway track, railway subgrade bears a huge dynamic load from trains. To explore the feasibility and dynamic characteristics of mixed filling of railway subgrade soil with tire debris, a series of large-scale indoor model tests were conducted to compare and analyse the magnitude and distribution of earth pressure, and the cumulative settlement displacement of sleepers, under two different loading conditions (i.e., single-stage cyclic loading and multi-stage cyclic loading). The results demonstrate that under all conditions, the vertical displacement at the sleeper ends is greater than that at the sleeper middle, the vertical displacement at the sleeper end decreases with the increase of static load and frequency, but increases with the increase of amplitude. Additionally, adding tire debris can help reduce the settlement and displacement of the subgrade soil, and the same amount of tire debris has the best effect when mixed in two layers. Moreover, multi-stage cyclic loading can significantly reduce the cumulative settlement of the subgrade soil. Under multi-stage cyclic loading, the settlement displacement at the end of the subgrade soil sleeper is larger than that at the middle of the sleeper, but the difference gradually decreases as the static load increases. It is revealed from the research that tire debris can significantly improve the performance of railway subgrade soil.