A review of constitutive models for cement treated clay

Construction activities have considerably increased during the past few decades as a result of rapid population growth and industrial development leading to use ground previously considered unsuitable for construction. 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 methods. When cement is mixed, characteristics of soft clay change considerably increasing the strength and reducing compressibility. A number of constitutive models have been developed to describe the key features of the cement treated clay. Majority of the currently available models are developed within the framework of critical state soil mechanics. Other models are developed by combining bounding surface plasticity and kinematic yield surface concepts. These models include important aspects of cement treated clay such as destructuration, creep, relaxation, rate dependence and anisotropy. A simple model incorporating few model parameters with physical meaning, which can be quantified using standard laboratory tests, is essential to simulate boundary value problems in geotechnical engineering involving cement treated clay. However, currently no such model is available. This paper reviews existing constitutive models that can be used for simulation of cement treated clay and examines the limitations of these models in solving boundary value problems in geotechnical engineering.