Abstract
To determine the properties of bentonite in an unsaturated condition, which is typically used in the initial placement of the clay liners in landfills, the effect of the soil fabric on the mechanical properties of unsaturated compacted Kunigel-V1, a bentonite clay, and NSF Clay, a non-swelling clay, were investigated. Samples were prepared at varying gravimetric water contents, ranging from natural to 70%, with the use of distilled water. The soil fabric was studied using scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP). The mechanical behaviour was studied by constant rate of strain (CRS) consolidation testing and constant volume direct shear (CVDS) testing. The results indicate that while an increase in water content resulted in the formation of aggregates and an increase in shear strength, it was the dilatancy behaviour that was most affected. The saturation of Kunigel-V1 resulted in a decrease in the friction angle, from 40.4° to 20.4°, while the saturation of NSF Clay resulted in a decrease in friction angle from over 40° to 32.3°.
