| Budget Amount *help |
¥17,940,000 (Direct Cost: ¥13,800,000、Indirect Cost: ¥4,140,000)
Fiscal Year 2021: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2020: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2019: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2018: ¥3,770,000 (Direct Cost: ¥2,900,000、Indirect Cost: ¥870,000)
Fiscal Year 2017: ¥7,800,000 (Direct Cost: ¥6,000,000、Indirect Cost: ¥1,800,000)
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| Outline of Final Research Achievements |
To understand soil freezing and thawing under various moisture and temperature environments, laboratory experiments and numerical analysis were performed. Solute transport from unfrozen to frozen soil was verified, and change in the soil freezing point and freezing rate depending on the solute transport were clarified as well as condensation of solute into unfrozen water in the frozen soil. When water infiltrate into dry frozen soil, five temperature regions were appeared. And, organic decomposition and nitrification in soil under the frozen soil was investigated. It was suggested that soil water flow enhance the mineralization and nitrification in the soil. For frost heaving, effects of anisotropy of groundwater supply route to freezing front, and solute and foreign substances in the soil were elucidated. We also proposed ideas to improve soil freezing model, such as non-equilibrium freezing and thawing of soil water and feasible surface boundary conditions.
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