Next Article in Journal
Integrated Reporting as an Academic Research Concept in the Area of Business
Previous Article in Journal
How CEO Political Connections Induce Corporate Social Irresponsibility: An Empirical Study of Tax Avoidance in South Korea
Previous Article in Special Issue
Smart Collaborative Performance-Induced Parameter Identification Algorithms for Synchronous Reluctance Machine Magnetic Model
Article

Mechanism of Sleeper–Ballast Dynamic Impact and Residual Settlements Accumulation in Zones with Unsupported Sleepers

1
Department of Planning and Design of Railway Infrastruckture, Institute of Railway Systems and Public Transport, Technical University of Dresden, 01069 Dresden, Germany
2
Department of Rolling stock and Rail Track, Lwiw affiliation of Dnipro National University of Railway Transport, 79052 Lwiw, Ukraine
3
MOE Key Laboratory of High-Speed Railway Engineering, Southwest Jiaotong University, Chengdu 610031, China
*
Author to whom correspondence should be addressed.
Academic Editors: Yang Song, Hongrui Wang and Yongqiu Zhu
Sustainability 2021, 13(14), 7740; https://doi.org/10.3390/su13147740
Received: 1 July 2021 / Revised: 8 July 2021 / Accepted: 9 July 2021 / Published: 11 July 2021
Unsupported sleepers or void zones in ballasted tracks are one of the most recent and frequent track failures. The void failures have the property of intensive development that, without timely maintenance measures, can cause the appearance of cost-expensive local instabilities such as subgrade damages. The reason for the intensive void development lies in the mechanics of the sleeper and ballast bed interaction. The particularity of the interaction is a dynamic impact that occurs due to void closure. Additionally, void zones cause inhomogeneous ballast pressure distribution between the void zone and fully supported neighbour zones. The present paper is devoted to studying the mechanism of the sleeper–ballast dynamic impact in the void zone. The results of experimental in situ measurements of rail deflections showed the significant impact accelerations in the zone even for lightweight slow vehicles. A simple three-beam numerical model of track and rolling stock interaction has shown dynamic interaction similar to the experimental measurements. Moreover, the model shows that the sleeper accelerations are more than 3 times higher than the corresponding wheel accelerations and the impact point appears before the wheel enters the impact point. The analysis of ballast loadings shows the specific impact behaviour in combination with the quasistatic part that is different for void and neighbour zones, which are characterised by high ballast pre-stressed conditions. The analysis of void size influence demonstrates that the maximal impact loadings and maximal wheel and sleeper accelerations appear at a certain void depth, after which the values decrease. The ballast quasistatic loading analysis indicates an increase of more than 2 times in the ballast loading in neighbour zones for long voids and almost full quasistatic unloading for short-length voids. However, the used imitation model cannot explain the nature of the dynamic impact. The mechanism of the void impact is clearly explained by the analytic solution using a simple clamped beam. A simplified analytical expression of the void impact velocity shows that it is linearly related to the wheel speed and loading. The comparison to the numerically simulated impact velocities shows a good agreement and the existence of the void depth with the maximal impact. An estimation of the long-term influences for the cases of normal sleeper loading, high ballast pre-stress and quasistatic loading in the neighbour zones and high impact inside the void is performed. View Full-Text
Keywords: ballasted track; unsupported sleepers; sleeper–ballast dynamic impact; dynamic simulation; analytic solution; discrete element modelling ballasted track; unsupported sleepers; sleeper–ballast dynamic impact; dynamic simulation; analytic solution; discrete element modelling
Show Figures

Figure 1

MDPI and ACS Style

Sysyn, M.; Przybylowicz, M.; Nabochenko, O.; Liu, J. Mechanism of Sleeper–Ballast Dynamic Impact and Residual Settlements Accumulation in Zones with Unsupported Sleepers. Sustainability 2021, 13, 7740. https://doi.org/10.3390/su13147740

AMA Style

Sysyn M, Przybylowicz M, Nabochenko O, Liu J. Mechanism of Sleeper–Ballast Dynamic Impact and Residual Settlements Accumulation in Zones with Unsupported Sleepers. Sustainability. 2021; 13(14):7740. https://doi.org/10.3390/su13147740

Chicago/Turabian Style

Sysyn, Mykola, Michal Przybylowicz, Olga Nabochenko, and Jianxing Liu. 2021. "Mechanism of Sleeper–Ballast Dynamic Impact and Residual Settlements Accumulation in Zones with Unsupported Sleepers" Sustainability 13, no. 14: 7740. https://doi.org/10.3390/su13147740

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop