Behavior of Natural Fine Soil Particle Dispersions in Nonaqueous-Phase Liquids

Understanding and quantifying particle-fluid interaction (PFI) is of fundamental importance for such geoenvironmental issues as polluted soil behavior, transport of organic contaminants in porous media, and the behavior of slurries in contact with nonaqueous-phase liquids (NAPLs). NAPLs have a very low dielectric permittivity in comparison with water, and therefore significant changes in soil properties can be expected as a consequence of PFI. This study evaluates interactions between soil particles and NAPLs using the rheology measurement of loess silt, zeolite, and bentonite particle concentrated dispersions. The dispersing liquids were kerosene, two paraffin oils with different viscosities, and deionized water (DIW) as a reference liquid. The results show the influence of the volumetric content of particles on the undrained shear strength of dispersions. The effects of suspending fluid viscosity and the magnitude of PFI were analyzed in a novel way by comparing the volume of particles for which the dispersion presents an undrained shear stress of 1 Pa determined for two different fluids. These results highlight the importance of PFI in the macroscopic properties of soils, hydraulic conductivity, and liquid limit. (c) 2020 American Society of Civil Engineers.