Three-dimensional nonlinear analysis for temperature characteristic of ventilated embankment in permafrost regions

A ventilated embankment with pipes inside is proposed for application in the field. The pipeʹs diameter is 0.4 m; its position is 1.0 m above the natural surface; and the distance between its centers is 2.0 m. Using the finite element method, the three-dimensional numerical analysis for the temperature characteristic of the ventilated embankment has been performed. The calculated result indicates that the ventilated embankment enables the area of thawing bulbs under it to decrease, the largest thawing depth to shrink, and the isotherm of 0 °C to move up into regions at which the yearly average air temperature is −2.9 °C, or the yearly average temperature on the natural surface is −0.4 °C without climatic warming. This illustrates that the ventilated embankment is able to play a cooling role to the permafrost under it and is able to reduce the embankment base temperature, which ensures the stability of embankment in permafrost regions. Considering the case where the air temperature will increase by 2 °C in 50 years, the ventilated embankment structure used for 50 years can also ensure the thermal stability of permafrost under it in the regions where the yearly average air temperature is below −3.5 °C, or the yearly average temperature on natural ground surface is below −1 °C.