An experimental study on static solid-liquid phase equilibrium in the pores of a porous medium

The so-called Clausius-Clapeyron equation, that is, the static equation of state for “solid-liquid-porous media” systems without liquid flow through the pores, has been experimentally examined by measuring the pore liqiud pressure at the solid-liquid interface in order to verify the accuracy of our method of measuring unfrozen pore liquid pressure. Several series of experiments have been carried out using water-saturated Ohya-Tuff as a porous medium specimen cooled from the top down. In these experiments, the solid-liquid interface was always fixed at the top surface of the specimen. The experimental results imply that the measurement method should be useful in determining the relative value of the unfrozen pore water pressure.