A numerical model of the coupled heat transfer for duct-ventilated embankment under wind action in cold regions and its application

Abstract

The duct-ventilated embankment, as a special embankment structure, has been used to protect the underlying permafrost from thawing in Qinghai-Tibetan railway construction of China. For cold regions engineering, the temperature is the most important factor that determines the stability of construction, and wind can directly affect the temperature distribution in the construction. To research the stability of the duct-ventilated embankment under wind action, based on the wind, temperature and geology conditions of Qinghai-Tibetan Plateau, a three-dimensional numerical model of the coupled heat transfer for duct-ventilated embankment, which was composed of the air convective heat transfer problem between inside and outside duct, the coupled heat transfer problem between airflow and duct wall, and the heat conduction problem with phase change in roadbed, was analyzed to determine the temperature and velocity characteristics in the ventilated duct, as well as the temperature fields of the duct-ventilated embankment. The numerical model can reasonably solve the coupled heat transfer problem for duct-ventilated embankment; furthermore, from the results, it was found that, on the assumption that the air temperature will be warmed up by 2.2 °C in the future 50 years and in the areas where the mean annual air temperature is − 4.0 °C, the duct-ventilated embankment structure can be an effective measure to decrease the ground temperature beneath it and ensure the stability of permafrost roadbed.