A Probabilistic and Mechanical Approach for Hysteresis of SWCC in Unsaturated Soil

The relationship between suction and water content in an unsaturated soil is called the soil-water characteristic curve (SWCC). The SWCC of unsaturated soils is hysteretic in nature. In this paper, a numerical model for hysteresis is proposed to simulate the main and scanning curves of the SWCC in an unsaturated soil based on KITA-ARA model and KITA-SAKO model in which the degrees of saturation under quasi-saturated and residual saturated conditions can be taken account of. The SWCC can be derived from KITA-ARA model and KITA-SAKO model in which compaction tests in addition to the index soil properties such as soil particle density, void ratio, grain size distribution, and surface tension of pore-water are only needed as input parameters. Then the hysteresis of SWCC can be drawn by introducing new concepts for the so-called ink-bottle model.