Updating the Design Map of Frost Indexes as a Prerequisite for Relevant Assessment of Track Substructure for Non-Traffic Load

Ižvolt, Libor; Dobeš, Peter; Pieš, Juraj

doi:10.2478/cee-2018-0015

Cited by 3 publications

(1 citation statement)

References 3 publications

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“…The material and technical characteristics of these structural layers R i , which are applied to the MODEL 4, are shown in Tab.1, where: λ -thermal conductivity, ρ -bulk density, c -specific thermal capacity and w -volume content of water. The characteristics were obtained directly in the accredited laboratory of the Railway Engineering Department in [6] and [7], in accordance with research activities of the VEGA [8] in 2016 to 2018 and some parts of [9] in 2017.…”

Section: Characteristics Of Layers Of Models and Load From The Externmentioning

confidence: 99%

Freezing of the Subballast Layers of the Railway Formation – High Embankment and Double Track

Hodas

Pultznerová

2019

Civil and Environmental Engineering

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In the paper, a numerical modelling experiment is presented in order to detect the temperature transition through the individual layers of the railway formation during the winter period that is their undesirable freezing. In the experiment, the temperature behaviour and the zero isotherm (0 °C) are investigated. We want to prove that the temperatures are also affected by the volume of mass in the railway formation. The modelling of new experiment has been carried out done on a low and also high embankment of single and double track railway, where the volume of material in the core of the formation is almost doubled. The experiment demonstrated that the greater is the mass of the subballast layers, the higher is the resistance to freezing due to the accumulated heat in the pre-winter period.

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Section: Characteristics Of Layers Of Models and Load From The Externmentioning

confidence: 99%

Freezing of the Subballast Layers of the Railway Formation – High Embankment and Double Track

Hodas

Pultznerová

2019

Civil and Environmental Engineering

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Static Modulus of Deformation of Uncemented Layers of the Railway Substructure—Comparison of Values and Determination of Correlation Dependence According to the Test Procedure of the Slovak Railways and Deutsche Bahn A.G.

et al. 2023

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The paper focuses on the analysis of the values of the static modulus of deformation obtained by the application of the test procedure specified in the methodology for the diagnostics of the sub-ballast layers used for German railways (DIN 18 134) and the Railways of the Slovak Republic (Regulation TS4). The purpose of the study was to determine the correlation between the measured values of the static modulus of deformation according to the above-mentioned methodologies based on a series of experimental measurements on an experimental field built at a scale of 1:1. It also aimed to develop a numerical model characterising the behaviour of the loaded environment during the experimental measurements using the finite element method, which can subsequently be used for the design of the structural composition of the sub-ballast layers. For the purpose of the experimental measurements, a sub-ballast layer of 0/31.5 mm crushed aggregate of different design thicknesses was applied to the sub-ballast layers. A polynomial dependence with a high value of the reliability coefficient can be found between the results of the static modulus of deformation obtained using the mentioned measurement methodologies during the quality inspection of the implemented construction works. This dependence is valid for the specific boundary conditions of the experimental measurements performed (subsoil of clay with gravel admixture and the sub-ballast crushed aggregate layer of 0/31.5 mm dolomitic gravel). In the future, establishing correlation dependencies for other boundary conditions and structural material compositions can be considered.

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Verification of boundary conditions of numerical modeling of the track substructure thermal regime – influence of the snow cover

Ižvolt

Dobeš

Pieš

2018

AoT

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The initial part of the paper briefly characterizes a long-term experimental activity at the Department of Railway Engineering and Track Management (DRETM). The research of the DRETM focuses, besides other research activities and specific problems in the field of railway engineering (application of new structures and construction materials in conventional and modernized railway tracks, modernisation and rehabilitation of existing railway tracks for higher speeds, track diagnostics, influence of track operation on noise emissions and design of structural measures, possibility of application of recycled ballast bed material in the track substructure, ballast recycling technologies, ecological assessment of recycled material of the track substructure), on various factors affecting track substructure freezing. In 2012-2017, in the campus of the University of Žilina (UNIZA), an Experimental stand DRETM was built for the research purposes. The experimental stand DRETM consists of 6 types of track substructure placed in an embankment or a cut, in the 1:1 scale. Besides conventional building materials (crushed aggregate), these structures also include various thermal insulation materials (Liapor concrete, Styrodur, foam concrete). A significant part of the paper deals with numerical modeling of the freezing process of track substructure (an embankment with the embedded protective layer of crushed aggregate, fr. 0/31.5 mm) for various boundary conditions (air frost index, average annual air temperature), using SoilVision software. The aim of this research is to identify the thermal insulation effects of different thicknesses of snow cover on the depth of penetration of the zero isotherm into the track substructure (railway track). The paper conclusion specifies the influence of different snow cover thicknesses, or nf factor (factor expressing the dependency between the mean daily air temperature and the temperature on the ballast bed surface) and various climatic conditions (frost indexes and average annual air temperatures), affecting the railway infrastructure, on the resulting depth of freezing of the track substructure (railway track). These outputs will be in the further research used for the design of nomogram for determining the thickness of the protective layer of the frost-susceptible subgrade surface of the track substructure.

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Updating the Design Map of Frost Indexes as a Prerequisite for Relevant Assessment of Track Substructure for Non-Traffic Load

Cited by 3 publications

References 3 publications

Freezing of the Subballast Layers of the Railway Formation – High Embankment and Double Track

Freezing of the Subballast Layers of the Railway Formation – High Embankment and Double Track

Static Modulus of Deformation of Uncemented Layers of the Railway Substructure—Comparison of Values and Determination of Correlation Dependence According to the Test Procedure of the Slovak Railways and Deutsche Bahn A.G.

Verification of boundary conditions of numerical modeling of the track substructure thermal regime – influence of the snow cover

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