Effect of organic fluids on the geotechnical behavior of a highly plastic clayey soil

Abstract Changes in pore fluid distribution generally exert a significant influence on the geotechnical behavior of clays. To determine these influences, we used four different organic fluids (methanol, ethanol, isopropyl alcohol and acetic acid) at various organic fluid/water ratios, covering a wide range of dielectric constants. Firstly, the specimens were consolidated using a 100 kPa pre-consolidation pressure. Then, a series of triaxial compression and consolidation tests were executed on the water-organic fluid slurries. Additionally, Atterberg limit tests were conducted. The coagulation of the clay particles was studied with an optical microscope. Liquid limit values and consolidation parameters generally decreased while shear strength values increased with increasing organic fluid/water ratio and decreasing dielectric constant of the pore fluid. The effect of the pore fluids is attributed to the decreasing electrostatic repulsion. During coagulation, the particles showed a tendency to behave like silt-fine sand.