Experimental study of frost heave mechanism

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To clarify the mechanism of frost heave phenomena, the following experiments are performed.1. Frost heave experiments using high frost susceptible soil and porous plates.2. Experiments on unfrozen water migration under the electrical field.3. Mesurement of unfrozen water content and unfrozen film thickness using neclear magnetic resonance.4. Molecular dynamics study of fluid behavior adjacent to rigid wall.The following results are obtained by this study1) We obtained the relationship between the ice segregation rate and the temperature of ice segregating surface by using layred porous plate. The experimental results showed that the ice segregation rate decresed with decreasing temperature of ice segregating surface. This was explained by the decresing unfrozen water content and increasing water viscosity with decreasing temperature.2) From a replica of vertical section of frozen sample after the frost heave experiment, the ice content was obtained with image analysis. From the experimental results, the relationship was obtained between the segregated ice content and freezing speed and temperature gradient.3) From the frost heave experiments under the electrical field, the movement of unfrozen water was measured. The result showed that the amount of electro-osmotic flow was conperable to the water redistribution during freezing.4) The unfrozen water content of frost susceptible soil was measured with neuclear magnetic resonance. The average unfrozen film thickness was calculated with total specific surface area. The results are compared with the calculated results using Van der Waals force and electric double layr.5) From the molecular dynamics study of fluid adjacent to the wall, the fluid near the wall behaved as soilid like and the self-diffusion constant became one order smaller than the bulk state.