Consolidation and shear behaviour of kaolinite-bentonite clay mixtures

Abstract

This thesis consisted of three parts: consolidation characteristics variation, shear strength behaviour and resistivity analysis of different kaolinite-bentonite clay mixtures with various pore fluid salinity levels. The 1-D oedometer tests were performed to determine the consolidation characteristics of kaolinite-bentonite clay mixtures with different pore fluid salinity levels. The samples were prepared at a moisture content level of 2% above the respective liquid limit of each clay sample mixture. The behavioural pattern of the measured coefficient of consolidation (Cv) and the compression index (Cc) of the clay mixtures with the key influencing factors such as salinity level of pore fluid (pore fluid chemistry) and mineral composition were analyzed in detail. Direct shear box tests were also conducted to study the shear behaviour of different clay mixtures. For the simple direct shear test, thin disk samples of 2 to 3 mm thicknes and 60 mm diameter were prepared by mixing different kaolinite-bentonite clay mixtures with different pore fluid s. The clay samples were sheared back and forth until they reached a residual stress state. The peak, residual stress values and the residual friction angle variations were analyzed in detail. Resistance variations of different clay mixtures were measured using the inductance-capacitance-resistivity meter (LCR meter) at a higher frequency level of I O kHz and the results were used to study the porosity variation of the clay mixtures using Archie's equation.