高速列车与路基冻胀相互作用机理

针对高速铁路路基中低含水率、远离地下水的级配碎石等冻胀不敏感性粗颗粒土,却普遍发生冻胀的特殊现象,提出了一个简洁的#x0201c;循环动载诱发冻胀#x0201d;模型,认为高速列车循环荷载会导致地下水位以下饱和地基土中超静孔隙水压力的发展,进而将地下水#x0201c;泵送#x0201d;至冻结线以上,从而为土中独立冰层的形成,及冻胀的发生持续地提供#x0201c;原材料#x0201d;。模拟结果表明,本模型能够很好的揭示上述特殊工程现象发生的原因；同时,新模型对循环荷载诱发冻胀机理的阐述,也为季节性冻土区高速铁路路基冻胀防治研究提供了一种新的思路。

Effects of train loads on frost heave of embankments

Substantial frost heave is observed in coarse fills in high-speed railway embankment. These coarse fills have very low water content and are located above the groundwater. In an attempt to explain the unexpected frost heave, it is proposed that the cyclic train loads cause the development of the excess pore water pressure in the underlying subgrade soils and hence #x02018;pump#x02019; up the water to the frost front, which in turn feeds the formation of ice and results in continuous frost heave. A simple quantitative model is developed to simulate the pumping-enhanced frost heave. The numerical results show that the proposed mechanism can indeed provide a legitimate explanation for the otherwise unexpected frost heave. The engineering implications of this new frost heave mechanism are also discussed, in the context of designing frost heave mitigation measures in seasonally frozen regions.