An Elasto-Plastic Constitutive Model for Cement Treated Soil Based on Super-Subloading Yield Surfaces

In cement treated soil, bonding structures which consist of soil particles and cement hydrate affects the mechanical behaviors (peak strength, softening and dilatancy). Micro cracks of the bonding structure gradually appears with the development of deformation, which induces degradation of cementation strength. In this work, a coupled elastic-damage-plasticity effect is considered and evolution rules of cementation strength with plastic shear strain are proposed. In addition, within the framework of the Super-Subloading Yield Surfaces, an elasto-plastic constitutive model is proposed for cement treated soil to consider other mechanical behaviors such as the decay of soil structure and loss of consolidation. Triaxial compression drained tests for cement treated soils under different confining pressure have been used to investigate the validity of the proposed model. A good agreement between the experimental results and the model is obtained. It can be found that the degradation of cementation affects the tendency of dilation. Higher confining pressure inhibited the development of the micro crack of the bonding structure.