Comparison of Two Drying/Wetting Methods for Assessing the Influence of Drying/Wetting on the Mechanical Cyclic Behaviors of Soils

The purpose of this study was to investigate the impact of drying/wetting methods on the mechanical cyclic behaviors of unsaturated soils. A series of cyclic triaxial tests were conducted on unsaturated specimens that experienced different drying/wetting histories. The specimens that experienced drying/wetting histories have lower degrees of saturation on the drying path than the initial specimens at a given suction. The cyclic triaxial test results indicate that the specimens that experienced drying/wetting histories have higher cyclic strength than the initial specimens due to the fact that the contribution arisen from irreversible compression during drying/wetting process outweighs the influences triggered by development of micro-cracks and lower degree of saturation. The cyclic strength of the specimens that experienced oven-drying and vacuum saturation process was found to be lower than that of the specimens that experienced air-drying and vacuum saturation history. This relatively lower cyclic strength attributed to the development of micro-cracks during oven-drying and vacuum saturation process was slightly more significant than those during air-drying and vacuum saturation process.