Resistance characteristics of Y-shaped sleepers for ballasted track under slope influence

The stability of ballasted track is significantly influenced by ballast bed resistance, which inevitably decreases on steeply graded track. Y-shaped sleepers generate considerable ballast bed resistance, but current studies exhibit a research gap in analyzing the performance of resistance variations for Y-shaped sleepers on steep railway slopes. In order to study the mechanical characteristics of the ballasted track with Y-shaped steel sleepers, a discrete element model of the ballast bed for a large-slope railway is established, and its accuracy is validated. The changes of longitudinal and lateral resistance of the ballast bed and the characteristics of the ballast bed resistance of the Y-shaped steel sleeper applied to different slope lines are analyzed. The results show that both the longitudinal and lateral resistances of the ballast bed can be modeled as linearly decreasing with increasing slope, with minimum values of 14.59 kN (longitudinal), 14.33 kN (lateral, tail to head), and 12.09 kN (lateral, head to tail), respectively. The longitudinal resistance provided by the sleeper sides, bottom, and end is minimally affected by the slope. The resistance contributed by the front Y limb increases progressively (from 66 % to 72 %), while the resistance from the rear Y limb decreases (from 11 % to 5 %). The ballast bed support stiffness exhibits a maximum reduction of 18.21 %. Affected by the slope, the longitudinal resistance of the Y-shaped steel sleeper is reduced more than the lateral resistance. The amplitude and influence zone of the longitudinal stress experienced by the ballast are increased with the slope. The study indicates that despite the reduction in resistance characteristics of the Y-shaped sleeper-ballast system due to slope influence, it still maintains high performance.