During the construction of clay core rockfill dam in cold regions in winter, the heat transfer characteristics of gravelly soil are important to the anti-freezing control of the core. Laboratory experiment and field test data showed that the frost depth of gravelly soil in unconsolidated state was deeper than that in compacted state at the early period of soil freezing. With the increase of the freezing time, however, the frost depth of compacted soil is deeper than that of unconsolidated soil. Further study showed that this phenomenon was main caused by the change of thermophysical parameters between unconsolidated and compacted soil. Under the same soil temperature, the thermal conductivity of compacted soil was approximately 2.6 times of that of unconsolidated soil, and the volume heat capacity and phase change latent heat of compacted soil was approximately 1.7 times of that of unconsolidated soil. The different thermophysical parameters caused the differences of the heat transfer rate, temperature distribution and heat release by cooling between compacted soil and unconsolidated soil. This study provides a theoretical guidance for freezing process of soil with different compactness and anti-freezing technology of clay core rockfill dam in cold regions.

冬季寒冷地区黏土堆石坝建设中，砾石土的传热特性对岩心的防冻控制具有重要意义。室内试验和现场试验数据表明，在土壤冻结初期，未固结状态的砾石土的霜冻深度要比压实状态的砾石土的霜冻深度深。然而，随着冷冻时间的增加，压实土壤的霜冻深度比未固结土壤的霜冻深度更深。进一步的研究表明，这种现象主要是由于未固结土和压实土之间热物理参数的变化引起的。在相同的土壤温度下，压实土壤的导热系数约为未固结土壤的导热系数的2.6倍，压实土壤的体积热容和相变潜热约为未固结土壤的1.7倍。不同的热物理参数导致压实土壤和疏松土壤之间的传热速率，温度分布和通过冷却释放的热量不同。该研究为寒区黏土堆石坝不同压实度的土壤冻结过程和防冻技术提供了理论指导。