Soil Sorptive Potential: Its Determination and Predicting Soil Water Density

Abstract

The soil sorptive potential (SSP) has been recently theorized as the physical source for matric potential and local pore-water pressure. It consists of four distinct physicochemical potentials with electromagnetic nature: van der Waals, electrical, cation and surface hydration, and osmosis. A general framework is developed to link the SSP, soil water density (SWD), specific surface area, and soil water retention curve (SWRC), providing an experimental way to determine the SSP and SWD functions. The experimentally determined SSP and SWD functions for different clays accord well with the theoretical SSP and measured SWD data, validating the framework. The parameters governing the SSP, i.e., Hamaker constant and structural parameters, are identified through inverse modeling of the water sorption isotherms (SWRC) of different clays, falling within the ranges reported in the literature and thus further confirming the validity of the SSP concept and its determination framework. The variability analysis of different clays, i.e., Georgia kaolinite, Wyoming montmorillonite, Denver claystone, and Denver bentonite, indicates that the SSP can vary up to 6 orders of magnitude, resulting in the same orders of magnitude change in compressive pore-water pressure and abnormal 1.3 g/cm3 in soil water density.