Abstract
Rock breakdown by freeze and thaw action occurs at bare slopes in mountainous area in Japan. The quantitative estimation of the amount of sediment produced is indispensable because the sediment closely relates to sediment disaster. In relation to this, it is required to obtain the temperature and moisture profile. In this study, a concurrent numerical simulation of underground heat and water transfer was conducted and the characteristic of water flow during freezing was discussed. In the analysis, a physical model of the pore structure change due to freeze-thaw was used. If the pore structure change occurred, which did not accompany the increase of porosity, considerably small amount of water was supplied to the freezing layer. However, if the increase of porosity was considered, upward water flux occurred which was large enough to increase volumetric water content. Moreover, it was revealed that the water flux positively correlates with freezing speed and with the amount of temperature fall.
