Numerical Model of Elasto-Plastic Electro-Osmosis Consolidation of Clays

Abstract

Electro-osmosis consolidation is an innovative and effective ground improvement method for soft clays. But electro-osmosis is also a very complicated process, as the mechanical behaviour, and the hydraulic and electrical properties of the soil are changing rapidly during the treatment process; this makes electro-osmosis hard to describe and simulate. Traditional electro-osmosis consolidation theory cannot provide a satisfactory solution because it does not directly consider the mechanical behaviour, nor the nonlinearity of the mechanical, hydraulic and electrical properties of the soil. A numerical solution for the electro-osmosis consolidation of clay in multi-dimensional domains is presented, with the coupling of the soil mechanical behaviour, pore water transport and electrical fields being considered. Three fully coupled equations are solved using classical finite elements. Furthermore, the Modified Cam Clay model is incorporated to describe the elasto-plastic behaviour of clay. The proposed model is first verified against a classical one-dimensional analytical solution for electro-osmosis consolidation to demonstrate its accuracy and efficiency. Then, an assessment of the impact of nonlinear soil behaviour is made by comparing numerical results with the results of an electro-osmosis laboratory test. The results show that the numerical solution can well predict the nonlinear behaviour of clay during electro-osmosis consolidation.