Comparison of Hydraulic Conductivity in Frozen Saturated and Unfrozen Unsaturated Soils
Comparison of Hydraulic Conductivity in Frozen Saturated and Unfrozen Unsaturated Soils
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DOI：
10.2136/vzj2015.11.0154
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发表时间：
2016-05-01
影响因子：
2.8
通讯作者：
Osada, Yurie
中科院分区：
文献类型：
--
作者：
Watanabe, Kunio;Osada, Yurie
了解冻土在融化温度附近的导水率对寒区农业管理和水量平衡计算以及人工地面冻结技术的应用具有重要意义。然而，对冻土导水率的测量一直是有限的。因此，常用温度和Clausius-Clapeyron方程来估算未冻土的非饱和导水率，但验证不足。在本研究中，我们同时测量了三种冻土的未冻水含量和导水率，并与蒸发法测得的未冻土的水分特征曲线和非饱和导水率进行了比较。利用测得的温度数据和水分特征曲线，Clausius-Clapeyron方程低估了冻土中的未冻水含量，这也导致了对水力传导性的低估，特别是在融化温度附近。然而，当冻土和冻土的液态水含量相同时，它们的导水率基本相同。冻土的水力传导性应根据液体(未冻结)水的含量而不是温度来估算。
Understanding the hydraulic conductivity of frozen soils near melting temperature is important in agricultural management and water balance calculation in cold regions and in the use of artificial ground freezing techniques. However, measurement of the hydraulic conductivity of frozen soils has been limited. Therefore, it is often estimated from the unsaturated hydraulic conductivity of unfrozen soil using temperature and the Clausius-Clapeyron equation, with inadequate validation. In this study, we simultaneously measured the unfrozen water content and hydraulic conductivity of three frozen soils by passing water through them and compared the results with water characteristic curves and unsaturated hydraulic conductivities of the unfrozen soils determined using the evaporation method. Using measured temperature data and water characteristic curves, the Clausius-Clapeyron equation underestimated unfrozen water contents in the frozen soils, which also resulted in underestimation of hydraulic conductivities, particularly near melting temperature. However, the unfrozen and frozen soils had similar hydraulic conductivities when their liquid water contents were the same. The hydraulic conductivity of frozen soil should be estimated from that of unfrozen soil based on the liquid (unfrozen) water content instead of the temperature.