Analysis of the relation between change of soil water phase and salt concentration by the measurement of dielectric constant in high frequency

不同材料之间的界面上出现了一些有趣的现象。本文从电磁现象的角度对盐渍土冻结锋即冻土与未冻土交界面处的现象进行了研究，通过室内土柱实验，证实了大量的显热发生在冻锋处，并通过冻土层传递到地表，释放到大气中。同时，随着土壤水分的积累，土壤中的液态水向冻结锋方向移动，土壤中的可溶盐也随之向冻结前沿移动。通过对土壤介电常数的测量，发现在高含盐量下，00C以下存在大量的未冻水，基于埋入土壤中的金属棒中传导的电磁信号在界面处反射的原理，发展了测量不同土壤界面深度的新技术。利用该技术可以精确测量冻结前沿，即冻土和未冻土之间的界面。由于土体冻结时热量、水和其他物质的运动是同时进行的，所以土体冻结现象非常复杂。因此，在冰冻锋面附近观察到了一些动态现象。研究了冰冻锋面的运动规律，推导了冰冻锋面的运动方程，并通过数值模拟验证了该方程能较好地预测冰冻锋面的运动。

Some interesting phenomena occur on the interface between different materials. In this study, the phenomena at the freezing front, that is a interface between frozen and unfrozen soil, are investigated for a saline soil on the view point of an electromagnetic phenomena.By the laboratory experiment for soil column, it is certified that much sensible heat occurs at the freezing front, is transferred through the frozen soil layer to the surface, and is released to the atmosphere. At the same time, it becomes clear that the soil water in liquid phase moves to the freezing front, and the soluble salt moves accompanied with the soil water to be accumulated there. By the measurement of dielectric constant of soil, it is recognized that much unfrozen water exists below 00C under the high salt concentration.The new technique to measure the depth of the interface between different soils is developed based on that the electromagnetic signal conducting in metal rod buried into soil reflects at the interface. The freezing front, that is, the interface between frozen and unfrozen soil, is precisely measured by this technique.The soil freezing phenomena are very complicated because heat, water and other materials are moved simultaneously by the soil frost. Some dynamic phenomena are, therefore, observed near the freezing front. The movement of the freezing front is investigated, and then the equation of the proceeding and receding of the front is derived and certified to predict well the movement of the front by the numerical simulation.