Stochastic coupling analysis of uncertain hydro-thermal properties for embankment in cold regions

In cold regions, the uncertain thermal property of embankment is an important basis for the safety design and construction. Especially for the high water content ground, the engineering properties are very complex and special because of the existence of moisture migration, which can cause a strong coupling effect for the stochastic hydro-thermal processes. In order to evaluate the uncertain hydro-thermal properties of embankment in cold regions, a stochastic analysis on coupled moisture migration, thermal conduction and ice-water phase transition is presented. The hydrothermal parameters are considered as random fields. A method to calculate local average variance from point variance is proposed, and a coupled modeling of stochastic hydro-thermal processes for the frozen soil is developed. The uncertain hydro-thermal behavior of an embankment along the Qinghai-Tibet railway is calculated by a stochastic coupling program, and the change rule of statistical characteristics for the temperature and unfrozen water content is obtained and analyzed. The study provides a new way to evaluate the stochastic hydro-thermal properties of embankment in cold regions, and it shows that water migration can promote uncertain heat transfer and increase the validation of temperature characteristic in frozen soil. The larger standard deviation of unfrozen water content is at the bottom of the embankment on July 15 and October 15. The average standard deviations of temperature and unfrozen water content increase with time, and the variability of uncertain hydro-thermal properties are becoming more and more obvious. These results can improve our understanding of the stochastic coupling effect of uncertain hydro-thermal process for embankment and provide a theoretical basis for design, operation and maintenance of embankment engineering in cold regions.