Compression of Partially Saturated Cohesive Soils

Laterally confined compression tests on Vicksburg silty clay compacted on the dry side of the optimum water content show that (1) there is virtually no outflow of pore water during compression while the degree of saturation increases from 70% to 97% (2) the samples are permeable to air under a small pressure gradient at degrees of saturation exceeding 90%; (3) for the same stress increment ratio, the time rate of compression is independent of sample thickness and drainage conditions; and (4) for virgin compression, the time rate of compression increases with increasing stress increment ratio. The findings provide basis for an analysis of the equilibrium state of pore fluids and its relation to the compression phenomena of partially saturated soil.