Field experiment and numerical simulation investigation on the mechanical properties of ballast bed with elastic sleepers

Under high-frequency impact loading, the ballast bed is prone to ballast crushing, deterioration, and other adverse effects. The use of elastic sleepers is an effective way to solve this problem. In order to investigate the macro-meso static and dynamic characteristics of the ballast bed with elastic sleepers, field static and dynamic experiments were carried out. A simulation model of the elastic sleeper-ballast bed based on DEM-MFBD coupling is established. The effects of laying elastic sleepers on the mass state, vibration characteristics, and contact relationship of the ballast bed are carefully analyzed. The results show that compared to the ordinary sleeper ballast bed, the lateral resistance and the resistance work of the ballast bed with elastic sleepers are reduced by 18.40% and 18.72%, respectively. The vibration acceleration of the rail and sleeper in the elastic sleeper line increases by 10.07% and 47.91%; while the vibration acceleration of the ballast bed decreases by 18.99%. The maximum energy frequency of the rail, sleeper, and ballast bed all decreases. Under the action of train load, the peak value of dynamic displacement of the elastic sleeper is 23.28% higher than that of the ordinary sleeper. The elastic sleeper can increase the number of contact points on the unit contact area between the bottom of the sleeper and the ballast particles, reduce the average contact force between the ballast particles, and mitigate the vibration impact of the sleeper on the ballast bed.