A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Engineering and Technology

Thesis (M.Eng.) - Asian Institute of Technology, 1982

The strength and collapse characteristics of a partially saturated compacted residual soil are controlled by the initial degree of saturation, dry density and matrix suction. Results of double odometer tests and double drained direct shear tests on compacted residual soil samples are reported. It is indicated that collapse in such samples is primarily controlled by initial degree of saturation, dry density, and hense matrix suction. The strength envelope for compacted samples is shown to be curved and it approaches the linear envelope for saturated samples at high stress. It is further shown that beyond the initial degree of saturation (50-60 per cent) collapse diminishes and is independent of applied stress. Suction pressure is related to the initial degree of saturation and for the same degree of saturation this value is higher than the virtual pre-consolidation pressure. It is suggested that elimination of matrix suction is the most promising mechanism governing both the amount and rate of collapse.