Application of TDR Test Probe for Determination of Moisture Changes of Railway Substructure Materials

This paper presents the results of numerical modelling of the influence of various factors (geometrical layout of the structural layers of the railway track, climatic factors and ballast fouling) on the freezing of railway track structure with a built-in thermal insulation layer of extruded polystyrene (Styrodur). At the same time, the suitability and expediency of incorporating the thermal insulation layer at the sub-ballast upper surface level (i.e. below the rail ballast construction layer), or at the level of subgrade surface are discussed. Numerical modelling results in the main factors that should be taken into account in the dimensioning of the sub-ballast layers with a built-in thermal insulation layer. Based on the data on the depth of freezing of the railway track structure obtained from numerical modelling, a design nomogram for dimensioning was created and subsequently the influence of the changes of climatic characteristics on the freezing of the railway track structure was then mathematically expressed.

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“…The de-Figure 1. Experimental stand DRETM-ground plan (Pieš & Môcová, 2019) Figure 2. Experimental stand DRETM -measuring profile no.…”

Section: Experimental Methods -Experimental Standmentioning

confidence: 99%

Numerical Modelling of Thermal Regime of Railway Track - Structure With Thermal Insulation (Styrodur)

Ižvolt

Dobeš

Holešová

et al. 2021

Journal of Civil Engineering and Management

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“…Before establishing the test sections, it was necessary not only to select suitable locations for monitoring the effects of railway traffic but also to select and calibrate suitable measuring and recording equipment. The calibration of the measuring equipment (in our case pressure and acceleration sensors) was performed within the experimental facility called the DRETM Experimental Stand [1]. The present experimental workstation has a steel frame with a movable crossbar, which can be used as a counterweight in the case of static load tests to determine the deformation resistance of various structural layers of linear transport structures.…”

Section: Methodsmentioning

confidence: 99%

“…The issue of stressing the trackbed layers has been investigated at the Department of Railway Engineering and Track Management (DRETM) in cooperation with other departments of the University of Žilina for a long time. The research activities initially focused on monitoring and subsequent numerical modeling of the effect of non-transport (climatic) loads on the construction of linear buildings [1][2][3]. Later, the research assessed the possibility of applying thermal insulation materials in the structural layers of linear buildings and, in some cases, also monitoring their deformation resistance (assessment of the static component of the traffic load) [4][5][6][7].…”

Section: Research Backgroundmentioning

confidence: 99%

Experimental Monitoring of Dynamic Parameters of the Sub-Ballast Layers as a Prerequisite for a High-Quality and Sustainable Railway Line

Ižvolt,

Dobeš,

Papánová

et al. 2024

Sustainability

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Monitoring dynamic load transfer from train traffic to sub-ballast layers is crucial for verifying the reliability and safety of railway lines, assessing the design cost-effectiveness and achieving minimum environmental impact. For this purpose, measurements in labs, in situ or modeling the influence of dynamic loads on the immediate and long-term roadway quality are often performed using suitable software. The available test sections enabled monitoring of the dynamic loads and optimizing the critical spots where increased dynamic effects from railway traffic may occur. The subject of this paper is the calibration of the sensors installed in the different test sections of the trans-European corridor number V. As a result, the necessary input parameters for the subsequent numerical modeling of the dynamic effects on the track substructure and vibration propagation on the available sections of the upgraded railway line were obtained. The sensor calibration was carried out on the experimental field, part of the Experimental Basis of the Department of Railway Engineering and Track Management. As part of the calibration, the sensitivity of the sensors embedded in the track bed to the applied dynamic loads resulting from the impact effects of the lightweight deflectometer was assessed. The result of the calibration was the demonstration of sufficient sensitivity of the sensors and their suitability for implementation in an actual railway track structure, with the aim of obtaining relevant values of the response of the sub-ballast layers to dynamic loads and assessing the operational impacts on the sustainable environment. Also, the main result of the research was the possibility of using the theoretical–experimental route to optimize the layers of the railway body.

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“…Here, the thermal-technical parameters of the materials applied to the sub-ballast layers were determined (Ižvolt et al, 2013). The water regime of the subgrade surface of all 6 structures of sub-ballast layers was also monitored using the TDR method (Pieš & Môcová, 2019). Currently, the DRETM research focuses on monitoring the traffic load, its static (on the experimental stand) and dynamic (on real experimental sections of modernised lines) components.…”

Section: Introductionmentioning

confidence: 99%

Assesment of the Possibility of Foam Glass Application in the Sub-Ballast Layers

Ižvolt

Dobeš

Holešová

et al. 2023

Journal of Civil Engineering and Management

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The paper investigates whether foam glass could reduce the structural thickness of the protection layer in the construction of the railway track (saving of natural materials – crushed aggregate) and, at the same time, also provide sufficient thermal protection of the frost-susceptible subgrade surface. It also discusses whether the incorporation of foam glass would have a relevant effect on the increase of the deformation resistance of the railway track structure at the level of the sub-ballast upper surface. Following these assumptions, the paper presents the results of experimental measurements of the deformation resistance of the modified structural composition of the sub-ballast layers (with an embedded foam glass layer) and their comparison with the results determined on a structure with a standard composition of the sub-ballast layers (crushed aggregate sub-ballast layer/protective layer). Also, numerical and mathematical analysis of the influence of the built-in thermal insulation foam glass layer on the reduction of the structural thickness of the protective crushed aggregate layer in terms of the effect of climatic factors is conducted in the paper. The mathematical model, developed by the research, provides the possibility of continuous monitoring of the change in the railway track structure freezing depending on climatic characteristics.

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Application of TDR Test Probe for Determination of Moisture Changes of Railway Substructure Materials

Cited by 9 publications

References 3 publications

Numerical Modelling of Thermal Regime of Railway Track - Structure With Thermal Insulation (Styrodur)

Numerical Modelling of Thermal Regime of Railway Track - Structure With Thermal Insulation (Styrodur)

Experimental Monitoring of Dynamic Parameters of the Sub-Ballast Layers as a Prerequisite for a High-Quality and Sustainable Railway Line

Assesment of the Possibility of Foam Glass Application in the Sub-Ballast Layers

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