季节性冻土地区铁路路基冻结深度变化规律研究

Study on Evolution Law of Frost Depth in Railway Subgrade at Seasonal Frozen Soil Region

对哈齐(哈尔滨—齐齐哈尔)客运专线DK221+150断面温度场进行实测,并对该断面温度场进行了二维有限元分析,研究季节性冻土地区铁路路基冻结深度变化规律及其影响因素,并拟合出冻结深度与热通量及持续冻结时间的函数关系。结果表明:该地区铁路路基最大冻结深度约0.3 m;路基冻结深度主要取决于浅层土体的热通量及持续冻结时间;当表层热通量降低至某一临界值后,土体冻结深度不再发展,冻土厚度开始逐步减少;冻结深度与热通量、持续冻结时间呈线性关系,随着冻结状态时间的延长,热通量的敏感性下降,持续冻结时间敏感性上升。

The temperature field of DK221+150 section of Harbin-Qiqihar passenger dedicated line was measured.The temperature field of the section was analyzed by two-dimensional finite element method,and the evolution law and influencing factors of the frost depth of railway subgrade in seasonal frozen soil region were studied.The function relationship between frost depth,heat flux and continuous freezing time was fitted out.The results show that the maximum frost depth of railway subgrade in this region is about 0.3 m.The frost depth of subgrade mainly depends on the heat flux of shallow soil and the duration of continuous freezing time.When the surface heat flux decreases to a certain critical value,the frost depth of soil will not develop,and the thickness of frozen soil will gradually decrease.The frost depth has a linear relationship with heat flux and continuous freezing time.With the prolongation of freezing time,the sensitivity of heat flux decreases and that of continuous freezing time increases.