Experimental investigation of the dynamic behavior of railway track with sleeper voids
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Experimental investigation of the dynamic behavior of railway track with sleeper voids Mykola Sysyn1
•
Olga Nabochenko2 • Vitalii Kovalchuk2
Received: 20 January 2020 / Revised: 4 August 2020 / Accepted: 6 August 2020 Ó The Author(s) 2020
Abstract The deterioration of the sleeper support on the ballasted track begins with the accumulation of sleeper voids. The increased dynamic loading in the voided zone and the ballast contact conditions cause the accelerated growth of the settlements in the voided zones, which results in the appearance of local instabilities like ballast breakdown, white spots, subgrade defects, etc. The recent detection and quantification of the sleeper voids with track-side and onboard monitoring can help to avoid or delay the development of local instabilities. The present paper is devoted to the study of the dynamic behavior of railway track with sleeper voids in the ballast breakdown zone. The result of the experimental track-side measurements of rail acceleration and deflection is presented. The analysis shows the existence of the dynamic impact during wheel entry in the voided zone. However, the measured dynamic impact is subjected to the bias of the track-side measurement method. Both the mechanism of the impact and the measurement aspects are explained by using the one-beam model on viscoelastic foundation. The void features in the dynamic behavior are analyzed for the purpose of track-side and onboard monitoring. A practical method of the void parameter quantification is proposed. Keywords Ballasted track Sleeper voids Ballast breakdown Track-side measurement Rail deflection Dynamic modeling Impact Identification
& Mykola Sysyn [email protected] 1
Institute of Railway Systems and Public Transport, Technical University of Dresden (TUD), Dresden, Saxony, Germany
2
Department of the Rolling Stock and Track, Lviv Branch of Dniprovsk National University of Railway Transport, Lviv, Ukraine
1 Introduction The ballast layer is one of the track elements that has the highest influence on track geometry quality and the maintenance costs that can reach up to 30% of the overall superstructure maintenance costs [1]. Ballasted track from the mechanical point of view is not the perfect structure due to a combination of the elastic elements like a sleeper– rail grid with loose ballast material. Therefore, the residual reformations of the ballast layer in the contact with sleeper are inevitable, taking into account the initial inhomogeneity of the ballast layer, subgrade, and dynamic loadings. The sleeper voids are the first symptoms of the sleeper support deterioration phenomenon. The following ones are the track geometry errors, ballast breakdown up to subgrade settlements, and defects [2]. Thus, the recent sleeper voids identification, monitoring, and the following maintenance planning are a good way of the ballast-driven maintenance costs reduction. One of the most extensive contributions in the research of the sleeper voids development is brought in the work [3], wher
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