Assessment of the effectiveness of two heat removal techniques for permafrost protection

Adaptation Methods for Transportation Infrastructure Built on Degrading Permafrost

“…Several projects based on numerical modelling have allowed optimisation of ACE materials and design (Chataigner et al, 2007;Goering and Saboundjian, 2004;Wang and Ma, 2012). Laboratory models have also been used to gather information on convective properties, to obtain data for numerical model calibration and to optimise design parameters under controlled conditions (Jorgensen et al, 2008;Zhang et al, 2006a). Different configurations of ACE have been tested and monitored at experimental sites and have demonstrated its effectiveness for thermal stabilisation of embankments built on thaw-sensitive permafrost in Alaska (Goering and Saboundjian, 2004;Xu and Goering, 2008), Canada (Doré et al, 2012;Gaumond et al, 2012;Malenfant-Lepage et al, 2012a, 2012b and China .…”

“…For this reason, a thin layer of crushed rock on north-facing embankment slopes and a thick layer on south-facing slopes may adjust the distribution of temperatures to be more symmetrical during summer (Lai et al, 2004). Also, the combination of a horizontal layer and a slope protection layer (referred to as a 'U shape' convective system) and the use of ventilation chimneys are likely to improve the effectiveness of ACE (Jorgensen et al, 2008). Recent monitoring results show that beneath a Ushaped ACE, the ground temperature of the permafrost from 4 to 10 m in depth was lowered by 0.5°C (Niu et al, 2015).…”

Optimization of embedded inclined open-ended channel in natural convection used as heat drain

“…Overall, the heat drain allowed elevating the maximal melting front and reducing ground temperature. Even though this 1D model is simplistic, it yields satisfactory results (the results are coherent with more complex modeling of the heat drain [8,24]) and is helpful and quick in a pre-design phase. This model is not intended to provide a detailed 2D or 3D transient temperature profile but rather to determine roughly the shoulder's main features required to elevate the active soil layer as high as required.…”

“…Another solution is a thermal drain installed in the embankment allowing outside cold air to flow in an internal chimney-like channel (natural convection) and thus, to extract more heat from the ground [8]. The heat drain concept -the object of this studyis relatively recent, and therefore, it has been scarcely documented in literature.…”

“…Among the most studied technological solutions are the convective embankment -which is a layer or a pile of stones in which Bé-nard convection and/or wind can enhance heat transfer from the * Corresponding author. ground to the air [2][3][4][5][6][7][8], and the duct-ventilated embankment [9,10] that rely on wind for cooling the soil. Reflective surfaces have also been studied to diminish the amount of radiation absorbed by the road [11].…”