多年冻土区宽幅XPS保温板路基传热特征研究

为研究宽幅XPS保温板路基地温调控效果，对共和至玉树高速公路21.5 m幅宽的XPS保温板路基和幅宽13.5 m热棒-XPS保温板复合路基试验路的冻土地温进行了长期系统的监测。结果表明:宽幅XPS保温板路基冻土上限年下降速率、冻土上限位置升温速率和吸热量分别为宽幅普通路基的76%，62%，55%，然而宽幅XPS保温板路基下伏多年冻土仍以较快的速率发生退化，上限下降速率达到0.5 m/a；铺设黑色路面后，宽幅XPS保温板路基和宽幅普通路基吸热量均增大约1倍；和单一的XPS保温板隔热措施相比，热棒-XPS保温板复合路基对路面下2～5 m范围内土层地温产生调控效果，可有效改善采用单一XPS保温板工程措施的被动吸热状态，提高冻土路基热稳定性。

Study on Heat Transfer Characteristics of Large-width Subgrade with XPS Insulation Board in Permafrost Regions

To study the regulation effect of ground temperature in large-width subgrade with XPS insulation board, long-term and systematic supervision on the frozen ground temperature was carried out along Gonghe-Yushu Highway in the test section which has the subgrade 21.5 m in width with XPS insulation board and the test section which has the composite subgrade 13.5 m in width with thermosyphon and XPS insulation board. The result shows that, as to large-width subgrade with XPS insulation board, the annual descending rate of the permafrost table, the rate of temperature rise and the heat absorption at the position of permafrost table were 76%, 62% and 55% of that of the ordinary-width subgrade, respectively, however, the permafrost underlying the large-width subgrade with XPS insulation board degrades at a relatively fast speed with the descending rate up to 0.5 m/a; after black pavement placed, both the large-width subgrade with XPS insulation board and the ordinary-width subgrade have the heat absorption doubled approximately; compared to the measure of XPS insulation board only, the composite subgrade with thermosyphon and XPS insulation board may regulate the ground temperature within 2~5 m depth of soil thereunder, improve the passive state of heat absorption and enhance the thermal stability of permafrost subgrade.