JUSTIFICATION OF THE PARAMETERS OF CHILLING ZONE OF LINING OF NEAR-ENTRANCE SITE OF LONG RAILWAY TUNNELS IN COLD SEASON
When operating long railway tunnels in harsh climatic conditions of Siberia and the Far East, there is a problem of tunnel lining freezing on near-entrance sites in the cold season. Due to the cyclical effects of negative outside temperatures, the surface layer of tunnel lining is constantly freezing and thawing, which causes rapid frost deterioration. This effect is especially pronounced for tunnels with closing near-entrance gates and one-way train traffic on the exit site. This is explained by the fact that at each train passage through the exit site, a significant amount of cold atmospheric air enters the tunnel. The length of chilling zone and the temperature of tunnel lining in the “outside air - tunnel lining” contact zone from the exit site deep into the tunnel, depending on the technological and climatic parameters of the tunnel are justified by analyzing the results of computational experiment. The correctness of obtained regularities is justified by the convergence of experimental results and analytical calculations based on the displacement method.