Triaxial Behavior of Kaolinite in Different Pore Fluids

Due to the existence of physicochemical effects, the pore fluid type generally has a significant influence on the geotechnical behavior of clays. The present paper focuses on the stress-strain and shear-strength behavior of kaolinite in various pore fluids. Kaolinite specimens, initially prepared by 1D consolidation of kaolinite/water slurries, were isotropically consolidated in a triaxial cell to the desired consolidation pressure. The specimens were then leached with the desired fluid and sheared under undrained condition to failure. Six different fluids including water, formamide, ethanol, acetic acid, triethylamine, and heptane were used. It was observed that leaching with certain fluids converts the otherwise normally consolidated specimens into overconsolidated specimens with respect to the stress-strain behavior of the soil. As a result of the apparent overconsolidation, the shear strength of the triaxial specimens increases. The results are discussed in relation to the change in physicochemical factors. A possible cause of apparent overconsolidation is presented, with some supporting physicochemical analyses.