A review of constitutive models for cement-treated clay

In situ deep cement mixing has become a popular ground improvement method due to its low cost and speed of construction compared to consolidation-based ground improvement methods. When cement is mixed with soft clay, characteristics of soil change considerably. A number of constitutive models have been developed to describe the key features of the cement-treated soft clay based on the critical state framework, bounding surface plasticity and the kinematic yield surface concept. These models include the most important aspect of cement-treated soft clay: the breakage of soil-cement structure during loading. This paper reviews existing constitutive models that can be used for the simulation of cement-treated clay and examines the limitations of these models. To model boundary value problems, a simple model utilising few model parameters is essential. Therefore, a simple model based on an extended version of the Mohr-Coulomb model is presented to simulate the cement mixed clay behaviour for which the model parameters can be conveniently derived from laboratory triaxial tests.