The unfrozen water content of various soils has been measured by calorimeter. The suction-moisture content characteristics of the same soils were also determined at room temperature, with conventional pressure plate and pressure membrane apparatus. Using the values of unfrozen water content measured during freezing, and the suction characteristics obtained during drying, a relation was found between the two sets of results. The relationship aproximates that of Schofield, between suction and initial freezing point, of soils at various moisture contents. Knowledge of the relationship permits prediction of the amount of water remaining unfrozen in a soil at negative temperatures down to -1.0 degrees C and often somewhat lower. Such prediction requires only determination of suction-moisture content characteristics by conventional methods together with a simple determination of the freezing point of an extract of the soil solution. In many cases, the accuracy of the prediction is apparently as great as can be obtained using even complex calorimetric methods. Using these relatively easily determined values of unfrozen water content at various temperatures, realistic estimates can be made of the apparent specific heats of frozen soils. The observed relationship provides a basis for studies of the effects of both load and temperature, on the proportions of ice and water in frozen soils and on the state of stress within the ice and unfrozen water.
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