Modelling of Snow Cover Thickness Influence on the Railway Construction Temperature Regime under Variable Weather Conditions

This article presents results of the modelling of temperature regimes of railway construction layers in application of the SV HEAT software. In one case, ambient air temperature affects the railway construction in presence of a snow cover and in another case - without it. Temperature changes in railway construction layers were modelled pursuant to the data of the Lithuanian Hydrometeorological Service of January-February 2015 in Vilnius region and the conducted field experimental studies. Ambient air temperature, moisture content in layers and snow cover thickness were assessed. Properties of the materials used to install railway construction layers were identified in the laboratory. Moisture content and temperature in construction layers were measured using sensors installed in the experimental field stand (DRETM II) set up in Slovakia. Modelling results have shown that the greatest temperature difference with a snow cover layer on the top railway construction and without it is 1.2 °C. These data revealed that a snow cover carried out the function of a thermal insulation layer. The railway construction with a snow cover had a lower freezing depth (difference of 0.5 cm). With increasing distance from the top of the ballast layer, the temperature of construction layers with a snow cover approaches the temperature of the construction without a snow cover, i.e. temperatures tend to approximate.