Analyzing factors impacting the thaw depth of the natural foundation soils under the railway embankment in the Tynda–Kuryan section of BAM

Abstract

Relevance. The reliability of roadbed on a thawing foundation is a relevant problem both for a new railway line and existing roadbed on permafrost soils. Among other things, design inaccuracies are the reason for deformations of roadbed on icy soils in the conditions of permafrost propagation. That is due to the use of calculation methods that do not take full account of the special nature of thermal and mechanical interaction between the roadbed and the thawing foundation. Research objective is to identify, based on the analyzed material, the relationship between the thaw depth of the natural foundation soils under the railway embankment and its height. Methods of research. An 8 km long section of a Baikal-Amur Mainline on the Kuryan – P.P. 2342 km (Tynda) stretch, with statistical indicators for 61 transverse profiles was taken as an object of research. To check the presence of a linear relationship between the thaw depth of the natural foundation under the roadbed floor and the embankment height, scattering diagrams were constructed and regression equations were found; the relationship nature and strength are determined using the Pearson correlation coefficient. The correlation coefficient reliability is assessed using the Student’s criterion. To assess the quality of the constructed regression model, the statistical significance of the determination coefficient is checked using the Fisher F-criterion. Research results. The calculations allowed to make a conclusion about the statistical significance of the correlation coefficient for the embankments of the two sample groups. The obtained Pearson correlation coefficients are significant, and between the studied features (i.e. the height of the embankment and the thaw depth of the natural foundation under it (in each group)) there is a close inverse relationship, for drainless surfaces the relationship is stronger. Conclusions. The correlation analysis performed in this article shows that the thaw depth of the natural foundation under the railway embankment and the embankment height have a close statistically significant inverse relationship. The analysis prepared according to experimental data gives only a general assessment of the dependence between natural foundation thawing and the embankment height at a local site.