UH model considering expansion of soils and its finite element implementation

The unified hardening model (UH model) for overconsolidated unsaturated soils is applicable to problems involving unsaturated soils. The wetting behaviors of unsaturated soils in overconsolidated condition can be described more reasonably using this model. It can also describe strain-hardening and softening behaviors of the unsaturated soils better. Based on the UH model for unsaturated soils, a new UH model for bentonite was proposed by considering the expansion of the soil aggregates. With just one more parameter, the proposed model can not only describe the stress-strain behaviors of the bentonite under general loading paths, but also describe the expansion of the bentonite under wetting paths. Based on the secondary development platform of finite element software, the UH model considering the expansion of the bentonite has been implemented. The subroutine was proved to be reasonable through the simulation of the triaxial test and the swelling pressure test using the proposed model.