Direct shear strength of a compacted unsaturated silty soil subjected to high total suction

摘要

Shear strength parameters of compacted soils are required for estimation of the stability of compacted earth structures. The flux boundary condition at the soil surface could result in high suction in the soil. The resulting high suction in unsaturated soils would change in response to rainfall and evaporation. There are deficiencies in unsaturated soil mechanics for soil with high suction. An empirical approach is essential for estimating the shear strength of desiccated soils. This study presents the results of a laboratory study on the shear strength of a compacted, unsaturated soil using a conventional direct shear apparatus. Prior to the application of a direct shear force, the compacted, unsaturated soil was desiccated using the vapor equilibrium technique. Shear strength of a desiccated soil was found to be lower than that of a compacted, unsaturated soil regardless of compaction effort. In addition, it was also observed that shear strength decreased substantially when soil suction was eliminated