Thermodynamic Stability and The Law of Corresponding States in Swelling Soils

Abstract

AbstractFollowing a heuristic suggestion by Groenevelt and Parlange, a thermodynamic description is given of a postulated order‐disorder transformation in a swelling soil. This transformation is shown to correspond to a phase transition of the second order at the air entry point, wherein the onset of a microscopic ordering process among the clay crystals in the soil occurs and there is a consequent discontinuity in the slope of the swelling curve. The available experimental swelling curves with which this prediction can be checked are organized on the basis of a new application of the law of corresponding states that permits all of the data to be plotted as a single, universal function of a reduced gravimetric water content variable. Scatter in the swelling curve data is sufficiently great at present to preclude a definite conclusion as to whether a second‐order phase transition actually occurs in swelling soil.