Coarse-grained soils were considered not susceptible to frost heave. However, substantial frost heave has been observed in unsaturated coarse fills in high-speed railway embankments. Recent experimental results in the literature show that vapour transfer has a considerable influence on the frost heaving of coarse-grained soil. However, vapour transfer has rarely been considered in modelling frost heave. This study presents a new frost heave model that considers vapour transfer and its contribution to ice formation. An updated computer program (PCHeave) is developed to account for the vapour transfer in unsaturated coarse-grained soils, where the rigid ice theory is applied to initiate ice lens formation in the frozen fringe. The results of the proposed model are compared with laboratory test results, which show reasonable agreement. The frost heave data monitored in 2013–2014 along the embankment of the Harbin–Dalian Passenger Dedicated Railway are also used to validate the proposed model. The prediction of the model agrees well with the measured results of frost heave and frost depth. This indicates that the proposed model can reasonably reflect the process of frost heave caused by vapour transfer in unsaturated coarse-grained soils.

粗粒土壤被认为不易冻胀。然而，在高速铁路路堤中，在非饱和粗填中已观察到大量的冻胀。文献中的最新实验结果表明，水汽传输对粗粒土的冻胀有很大影响。但是，在模拟冻胀时很少考虑蒸气转移。这项研究提出了一种新的冻胀模型，该模型考虑了蒸气的转移及其对冰形成的影响。开发了一个更新的计算机程序（PCHeave），以解决不饱和粗粒土壤中的水汽传递问题，在该土壤中，硬冰理论被应用来引发冰冻边缘冰晶的形成。将该模型的结果与实验室测试结果进行比较，这表明合理的一致性。哈尔滨至大连客运专线路堤2013-2014年监测的冻胀数据也用于验证该模型。该模型的预测与霜冻和霜冻深度的测量结果吻合良好。这表明所提出的模型可以合理地反映非饱和粗粒土中水汽传递引起的冻胀过程。