Abstract: Connecting the plastic component and the viscous component in parallel, then connecting these two components and the elastic component in series, yields the three component model, where each component has a unique nonlinear constitutive relation. Based on the three-component model, a elasto-plasto-viscosity model is proposed by considering the effects of wetting on the viscous component and the plastic component. The effects of wetting on the plastic component are described by a decrease in the inviscid yield stress at a fixed irreversible strain, while the effects on the viscous component are described by the increase of the rate-sensitivity coefficient. Both the effects on the two components can be fully determined based on test results. Subsequently, based on this collapse-rheology model, a numerical analysis is performed on the collapse-rheology behavior of Kaolin clay in a 1D consolidation test. In the test, the creep is observed in a dried condition, while the collapse is observed during the stepwise wetting. The water content and strain in the test are precisely measured. The validity of the analysis method is shown by the well simulated water content-strain-time relation and the definite difference between the collapse during wetting and the creep under dried condition.

Key words: humidification, kaolin clay, 1D consolidation, the three-component model