Assessing temperature dependence of soil water adsorption strength by molecular simulation

Abstract

Soil water adsorption strength represents the changing rate of adsorptive water content with regard to soil suction or water potential changes, dictating the magnitude of the soil water-retention curve at the dry end. Non-isothermal conditions are frequently encountered in energy and environmental geotechnics, posing the requirement to assess temperature effects on soil water adsorption strength. Yet, it remains challenging in assessing the temperature effects at the high suction range due to limitations in available experimental techniques. Here, the grand canonical Monte Carlo (GCMC) simulation was explored as a method to address this challenge. A series of GCMC simulations has been performed to assess the temperature effect on the external surface adsorption of three representative soil minerals – that is, K-muscovite, Na-montmorillonite and α-quartz. Molecular simulation results preliminarily reveal that the water adsorption strength of the external surface of these soil minerals only demonstrates marginal dependence on temperature. This observation is consistent with experimental results, substantiating the feasibility of the proposed method.