Cooling effect of combined L-shaped thermosyphon, crushed-rock revetment and insulation for high-grade highways in permafrost regions
DONG Yuan-hong1, 2, LAI Yuan-ming1, CHEN Wu1
1. State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; 2. CCCC First Highway Consultants Co., Ltd., Xi'an 710075, China
摘要 为维护多年冻土区宽幅高等级公路的热稳定性及保护下伏冻土，提出了一种 L 型热管–块碎石护坡保温板复合路基。为研究这种新型路基的降温效果，进行了室内模型试验，试验结果初步证明了这种路基的有效降温能力。为研究这种新型路基的长期效果，采用相关理论，结合室内模型试验的结果，依据青藏高原多年冻土区宽幅高等级公路的气温和地质条件，利用数值方法对有无 L 型热管的块碎石护坡保温板复合路基的温度特征进行了分析和比较。结果表明：在年平均气温为 - 4.0 ℃的青藏高原多年冻土区，考虑未来 50 a 气温上升 2.6 ℃的条件下，新的复合路基能够从整体上有效降低路基下土体的温度，确保高温多年冻土区宽幅高等级公路路基的热稳定性。
Abstract：In order to keep the thermal stability of large-width highway embankment in permafrost regions, a new type of cooling measure of combined L-shaped thermosyphon, crushed-rock revetment and insulation is presented. To examine its cooling effect, laboratory tests are carried out. The test results have preliminarily proved the effectiveness of the new cooling measure. To further validate its effectiveness in the service life of the highways in permafrost regions, based on relative theories and the laboratory test results, a numerical model for the highway embankment is established, and the temperature characteristics of the embankment in its service life are analyzed. The numerical results show that the combination of the L-shaped thermosyphon, crushed-rock revetment and insulation is effective to keep the thermal stability of the large-width embankment in its service life under the condition that the air temperature is warmed up by 2.6℃. Based on this, the new combined cooling measure is suggested to be used in the construction of large-width embankment in permafrost regions.