Abstract:

To study the influence of high thermal conductivity of thermal pipe on the temperature field of frozen soil under the subgrade in permafrost regions in the short term after subgrade filling, the temperature field change in the short term after subgrade filling was studied by numerical simulation method based on the coupling effect of water and heat. The results show that, due to the high thermal conductivity of the thermal pipe, the frozen front of the subgrade is concave along the thermal pipe in the short term after filling. Filling in June is easy to cause hydrothermal erosion at the slope toe and evaporation section；Filling in July, the lowest point of the freezing front is deeper than the embedded depth of the thermal pipe, which is the most unfavorable for the stability of the thermal pipe；Filling in August and September, the influence time of high thermal conductivity of hot rod is short. The effect of high thermal conductivity of thermal pipe on temperature field increases with the increase of filler temperature and thermal conductivity. In order to reduce the impact of high thermal conductivity of the thermal pipe in the short term after filling, construction from June to July should be avoided. During construction, the temperature of subgrade filler should be reduced as much as possible, and the thermal conductivity of the material can be appropriately reduced without affecting the cooling effect.

Key words: permafrost, thermal pipe, high thermal conductivity, temperature field, numerical simulation