In order to study the thermal-moisture dynamics of railway embankment in cold regions , the mois-ture , precipitation , temperature and heat flux data within embankments were extensively measured at ballast covered roadbed , ballastless gravel roadbed and natural ground in the embankment test section of Beiluhe per-mafrost region . Based on the observed data , the features of soil thermal-moisture migration , moisture accu-mulation and the effects of rainfall on the active layer of the embankment were analyzed . The results indicate that the temperatures in the active layer of the embankment varies sinusoidally with time . The ballast layer can effectively prevent the external heat flux reaching internal embankment and keeps a lower annual average value and annual range of temperature than the gravel roadbed . Water migrated towards the freezing front during the freezing process . Liquid water and rainfall infiltrate into the permafrost table during the thawing period . Heavy and sustained rainfall events have significant effects on short-term thermal-moisture dynamics in shallow subgrade(<75 cm) .But long-term thermal-moisture is not affected by rainfall and there are no obvious mois-ture accumulations in the embankment . The influence of the transport of liquid water and water vapor caused by rainfall infiltration and evaporation on the thermal-moisture dynamics of railway embankment should not be neglected .%为研究寒区铁路路基水热动态过程,以北麓河地区路基试验段道砟覆盖路面、无道砟路面(砂砾路面)和天然场地的水分、温度、热通量和降水等数据为基础,分析铁路路基活动层水热宏观迁移规律、活动层水分累积情况及降水对路基热状况的影响.结果表明:路基活动层各深度地温随时间呈正弦规律变化,道砟层能够有效减少外部热量进入路基,道砟路面年平均地温和年较差明显低于砂砾路面;融化期间路基液态水和降水向下运移,冻结过程中水分向冻结锋面运移;夏季强降雨和持续降雨对浅层路基(高度<75 cm)短期水热有明显影响,但路基长期水热受降雨影响不明显,也未出现明显水分累积;降雨入渗、地表蒸发伴随的液态水和水汽运移对铁路路基表层水热影响不可忽略.
展开▼
