隔热板埋深对冻土路基温度场的影响分析

Influence of Thermal Regime in Permafrost Embankment by Embedded depth of Insulation

采用焓模型,建立含相变的冻土路基温度场,利用非线性有限元方法对隔热板路基温度场进行数值模拟,并结合考虑近期及远期冻土保护效果,采用冻土年最大融深及路基内融土核高度两个评价指标综合分析了路基高度、路基施工季节等因素对隔热板最佳埋深的影响.有限元计算表明,当施工季节向冷季推迟3个月时,隔热板的冻土保护效果显著增强,路基在运营20年内无融土核出现.在确定隔热板最佳埋深时需综合考虑施工季节、路基高度等因素的影响,若路基较低,宜浅埋,路基高度较高,暖季施工宜中埋,冷季施工宜浅埋.

Enthalpy model and nonlinear finite element method（FEM） were adopted to simulate the thermal regime of embankments with insulations.Short-term and long-term permafrost protection effect were considered,and two index of annual max thaw depth and thawing soil height in embankments were adopted to analyze the influence on the optimal insulation depth by such factors as embankment height and construction seasons.FEM results show that if insulation embedding date is put 3 months off to cold seasons,the protection effect of insulation will increase significantly,and there is no thaw soil in embankments in their 20 years＇ service.In determining the optimal embedded depth of insulations,many factors such as construction seasons and embankments heights should be taken into account.For low embankments,insulations should be embedded shallowly.For high embankments,insulations should be embedded moderately if constructed in warm seasons,and shallowly if constructed in cold seasons.