Influence of mineral montmorillonite on soil suction modeling parameters

The emerging problems in the field of geotechnical engineering require a thorough understanding of the role of clay minerals and pore-water interactions on the unsaturated soil properties. Expansive soils have been the subject of intensive research since the early stages in the formulation of unsaturated soil mechanics principles. The expansive behavior of clays is mainly attributed to the presence of clay minerals such as Montmorillonite. Hence, it is hypothesized that there is a strong correlation between soil suction relationships and percent amounts of a specific clay mineral. In the present research, an attempt is made to establish the relationship between the percent Montmorillonite mineral (PMM) in a given soil and the corresponding soil water characteristic curve (SWCC) attributes, as the SWCC provides a relationship between matric or total suction behavior and pore size distribution in soils. For this research, one natural sandy soil was selected and mixed with three different percentages of Montmorillonite. Soil water characteristic curves of these soils were measured using methods like pressure plate and the WP4C potentiameter devices. SWCC data were analyzed along with three fitting models: Brooks and Corey, Van Genuchten, and Fredlund and Xing models. Model parameters determined are compared with the percent clay mineral in the soil. This analysis revealed the influence of PMM on the SWCC modeling parameters.