Effect of Suction on Shear Strength of Unsaturated Compacted Silty Sands under Low Confining Pressure

In order to evaluate the mechanical behavior of compacted soil under the low confining pressure, a series of the unconfined compression test under the constant water content in unsaturated state were performed on silty sand. The specimen used was made by the static compaction method. The shear strength, the negative pore water pressure and the volume change during the shear process were measured under the undrained condition. The shear strength and deformation behaviors under various densities were compared based on initial suctions of soils. As a result, UC test shows a possibility to apply the suction stress as a stress component to the peak and the post peak strength states under unsaturated conditions comparing with the failure lines of saturated state.