Abstract
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.
Highlights
IntroductionSome input parameters must be determined on the basis of knowledge and experience and verified by numerical modeling
The research of the Department of Railway Engineering and Track Management (DRETM) focuses, besides other research activities and specific problems in the field of railway engineering, on various factors affecting track substructure freezing
This paper is dedicated to the identification of influence of the snow cover thickness on the track substructure freezing. As this influence will be verified by numerical modeling of the thermal regime or track substructure freezing, it is necessary to state the method of entering the snow cover thickness
Summary
Some input parameters must be determined on the basis of knowledge and experience and verified by numerical modeling Such parameters include the influence of snow cover thickness as an active thermal insulation layer on the railway track surface on track substructure freezing. Various methods of entering must be compared and the design values for snow cover thickness for particular Slovak regions based on frost index IF and average annual air temperature θm must be specified In this way, it is possible to create conditions for identification of relevant influence of the snow cover thickness tsnow on the depth of track substructure (railway track) freezing DF. Dobeš, 2014), (Ižvolt et al, 2014), (Ižvolt and Dobeš, 2015), (Ižvolt et al, 2016), (Ižvolt et al, 2018a), (Ižvolt et al, 2018b)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
