Numerical simulation of full desiccation process of clayey soils using an extended DDA model with soil suction consideration

Soil desiccation is a common physical phenomenon, which causes many geotechnical problems to unsaturated clayey soils. In this paper, a proposed model was incorporated into the original Discontinuous Deformation Analysis (DDA) to simulate the full desiccation process of a clayey soil from volume shrinkage to desiccation cracking and then to desiccation curling by focusing on soil suction. In this model, evaporation-induced soil volume shrinkage and suction-induced tensile failure were separately considered, in particular, soil suction was reasonably treated as an equivalent attractive force rather than a strength parameter. Then, a constrained desiccation test was simulated using the extended DDA model, and obtained numerical results were compared with the experimental results. The comparison results show that this model can capture the main features of the full desiccation process of the clayey soil. Moreover, the influences of soil suction and sample thickness on the desiccation cracking and curling were investigated, which agrees with the laboratory observations. This work aims to propose a novel yet simple model to reproduce the key characteristics of the soil's full desiccation process, and the results demonstrate that the extended DDA model can be served as a promising approach to analyzing the full desiccation process of clayey soils.