Monitoring of Moisture Changes in the Construction Layers of the Railway Substructure Body and its Subgrade

Ižvolt, Libor; Dobeš, Peter; Pultznerová, lžbeta

doi:10.1016/j.proeng.2016.08.847

Cited by 14 publications

(13 citation statements)

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“…A prerequisite for developing a quality numerical model is the knowledge of relevant input data. This problem has been studied by the Department of Railway Engineering and Track Management since 2003 (Ižvolt et al, 2013), , , (Ižvolt and Dobeš, 2015), (Ižvolt et al, 2016), (Ižvolt et al, 2018a), (Ižvolt et al, 2018b).…”

Section: Review Of Literaturementioning

confidence: 99%

“…These data were requested to draw a new design map of average annual air temperatures θmd for the Slovak territory(Ižvolt et al, 2018b). Based on these inputs, combining frost indexes IF and average annual air temperatures θm was not demanding.,(Ižvolt et al, 2016),(Ižvolt and Dobeš, 2015). All the necessary input parameters for numerical modeling of the thermal regimefreezingof the railway track model are clearly stated in Tab.…”

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confidence: 99%

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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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Section: Review Of Literaturementioning

confidence: 99%

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confidence: 99%

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 particular values of the technical characteristics of the model materials were determined by the laboratory tests at the accredited laboratory at the Department of Railway Engineering (DRE). The heat-technical characteristics of the materials of the subgrade of TYPE 2 from the "in situ" model have been inputted to our modelling (Table 3), [6], and [8], where: λ -thermal conductivity, ρ -soil dry density, c -specific heat capacity, T ef and T ep -temperatures of freezing and thawing of the material, and W -material humidity. …”

Section: Model Loaded With Minus Temperaturesmentioning

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Modelling of Railway Track Temperature Regime with Real Heat-Technical Values for Different Climatic Characteristics

Hodas

Pultznerová

2017

Civil and Environmental Engineering

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High quality of railway track construction is a major priority. One of the quality elements is the resistance to load of railway formation with individual structural layers caused by negative temperatures during the critical freezing period of winter. Numerical modelling allows obtaining more control outputs at different climatic loads. The presented paper shows the load of railway track model with different variants of climate and shows the importance in the designing of the non-transport load under negative temperatures, i.e. observation of transition of the zero isotherm through the layers of railway subgrade. If the subgrade layers of the railway formation are built with high quality and durability then the axis of the track will keep its geometric spatial position during the long-time operation.

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“…Yra daug tyrimų, kuriuos atliekant vertinamas klimatinių veiksnių poveikis (Laurinavičius et al 2016;Ižvolt et al 2016;Yang et al 2015) transportui ir galimi būdai neigiamą poveikį mažinti. Šie tyrimai buvo atlikti JAV (Meyer 2008), Australijoje (Harvey et al 2004), Škotijoje (Galbraith, Price 2005), Didžiojoje Britanijoje…”

Section: įVadasunclassified

Moddeling of Negative Ambient Air Temperature Effect to Frost Depth of Lithuania Railroads Construction

Navikas

Sivilevičius

2017

Science - Future of Lithuania

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2017 © Straipsnio autoriai. Leidėjas VGTU leidykla "Technika". Šis straipsnis yra atvirosios prieigos straipsnis, turintis Kūrybinių bendrijų (Creative Commons) licenciją (CC BY-NC 4.0), kuri leidžia neribotą straipsnio ar jo dalių panaudą su privaloma sąlyga nurodyti autorių ir pirminį šaltinį. Straipsnis ar jo dalys negali būti naudojami komerciniams tikslams. Šaltojo periodo "ekstremalumas" GKK vertinamas pagal šalčio indekso dydį I m (Hodas et al. 2016). GKK įšalimo gylis yra apibrėžiamas kaip 0 °C gylis nuo GKK paviršiaus. Įšalimo gyliui įtakos turi šie veiksniai: neigiama AOT, kuri apibrėžiama šalčio indeksu; sluoksnių termoizoliacinės savybės; GKK sluoksnių medžiagų savybės (medžiagos rūšis, drėgmės kiekis w, tankis ρ, granuliometrinė sudėtis). MOKSLAS -LIETUVOS ATEITIS SCIENCE -FUTURE OF LITHUANIABaltijos šalių regiono klimato stebėsena atliekama nuolat (Ustrnul et al. 2012;Tietäväinen et al. 2010;Klavins, Rodinov 2010). Atlikti tyrimai apie globalią klimato kaitą rodo, kad laipsniškas klimato šilimas kartais neatspindi konkrečių regionų klimato pokyčių (Morice et al. 2012). Todėl tiksliai vertinti kiekvieną regioną arba jo dalį galima tik konkrečiai stebint kiekvienos meteorologijos stoties duomenis.Pagal Slovakijoje taikomą metodiką projektuojant ir parenkant PBS storį yra vertinama aplinkos oro temperatūros (AOT) įtaka GKK įšalimo gyliui.Darbo tikslas -sumodeliuoti GKK sluoksnių termodinaminį režimą, esant kintamai AOT (didžiausio šalčio indekso žiemai per 50 metų) ir nustatyti maksimalų įšalimo gylį. Vilniaus regiono duomenis ir atliktus lauko eksperimentinių tyrimų rezultatus, buvo sumodeliuota temperatūros kaita GKK sluoksniuose. Buvo įvertinta aplinkos oro temperatūra (AOT) ir drėgmės kiekis sluoksniuose. Laboratorijoje buvo nustatytos GKK sluoksniams įrengti panaudotų medžiagų fizinėsmechaninės ir termodinaminės savybės. Drėgmės kiekis ir temperatūra GKK sluoksniuose išmatuoti jutikliais, įrengtais eksperimentiniame lauko stende DRETM II Slovakijoje. Naudojant bandomojo ruožo duomenis, buvo sumodeliuota temperatūros dinamika GKK sluoksniuose, kintant aplinkos oro temperatūrai. Modeliavimo rezultatai rodo, kad, pritaikius Slovakijos nacionalinius GKK projektavimo ir vertinimo metodikas, Lietuvos GKK turėtų būti įrengiamos su storesniu pobalastiniu sluoksniu (PBS). Naudojant šalčiausios žiemos per penkiasdešimt metų rezultatus, gautas 2 m įšalimo gylis rodo, kad GKK įšalo daugiau nei 95 cm. APLINKOS ORO NEIGIAMOS TEMPERATŪROS ĮTAKOS GELEŽINKELIO KONSTRUKCIJOS ĮŠALIMO GYLIUI LIETUVOJE MODELIAVIMASReikšminiai žodžiai: geležinkelio kelio konstrukcija (GKK), aplinkos oro temperatūra (AOT), šalčio indeksas, įšalimo gylis, "SV HEAT" programa.

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Monitoring of Moisture Changes in the Construction Layers of the Railway Substructure Body and its Subgrade

Cited by 14 publications

References 1 publication

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

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

Modelling of Railway Track Temperature Regime with Real Heat-Technical Values for Different Climatic Characteristics

Moddeling of Negative Ambient Air Temperature Effect to Frost Depth of Lithuania Railroads Construction

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