|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1998 : ¥600,000 (Direct Cost : ¥600,000)
Fiscal Year 1997 : ¥400,000 (Direct Cost : ¥400,000)
Fiscal Year 1996 : ¥1,300,000 (Direct Cost : ¥1,300,000)
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.