气态水诱发高速铁路路基冻胀的潜在机理研究

针对我国严寒地区高速铁路路基中冻胀不敏感性粗颗粒填料大范围冻胀的现象,基于所提出的非饱和冻土水热耦合模型,阐述了气态水迁移成冰作用诱发非饱和路基冻胀的机理。结果表明:不考虑气态水迁移成冰作用时,产生的冻胀量几乎为0,而考虑气态水迁移成冰作用时,产生18.4 mm的冻胀,与实测值大致相同,且冻胀量与实测曲线吻合较好,冻结深度与哈大高速铁路路基四平段的实测值曲线吻合也较好,说明本文机理能够较好地解释上述冻胀现象发生的原因;与其他三种不同冻胀诱发机理的对比分析表明,严寒地区高速铁路路基冻胀是路基细粒含量、降水、地下水位等多种因素共同作用的结果,占据主导作用的因素需视具体工程情况判定。

Potential Mechanism of Vapor Induced Frost Heave in High-speed Railway Embankments

In severe cold regions in China,widespread frost heave was observed in high-speed railway embankments constructed by unsusceptible frost heave coarse fills.Based on liquid water-vapor migration model for unsaturated frozen soils,a potential frost heave mechanism for unsaturated embankments due to vapor migration was proposed.The results show that the predicted frost heave is nearly 0 mm without moisture transfer and phase change while the predicted frost heave is 18.4 mm which approximate the measured values with moisture transfer and phase change.The simulated frost depth matches well with measured curves in the Harbin-Dalian high-speed railway embankment.These two comparisons show that the mechanism proposed in this paper provides an explanation for the widespread frost heave phenomenon.The comparison with other three frost heave mechanisms shows that the frost heave in high-speed railway embankments is a coupled result of fine content,precipitation and groundwater table.The dominant factor should bedetermined according to practical engineering conditions.