Elastoplastic Coupled Model of Saturated Soil Consolidation under Effective Stress

Abstract

Soil’s consolidation is a geotechnical problem resulting from a stress-transfer process that initiates when the load is applied to the water contained in the soil, producing a reduction in pore water pressure and rearranging the solid particles, and thus causing a decrease in soil volume. Therefore, consolidation is a coupled flow–mechanical problem. Coupled models have been developed to simulate this phenomenon while considering different theories, providing consistent results. This paper presents an elastoplastic coupled model of consolidation under Terzaghi’s effective stress formulated using the equations of transient flow, balance moment, motion, and the critical state model that considered elastoplastic strains. The coupled model algorithm provided fast and easy results due to its flexibility, as it allowed combinations in loading and boundary conditions. Additionally, it considered the external/internal water flow as an inflow or outflow, which modified the pore water pressure and produced changes in the horizontal and vertical displacements. The numerical results obtained showed an appropriate behavior of the consolidation phenomenon, as well as the evolution of the vertical Uy and horizontal Ux displacements, water pressure pw, volumetric εv and deviatoric εq strain, mean σp and deviatoric σq stress, volumetric variation ∆εv, and elastic/plastic behavior of the finite elements while considering the yield surface of the critical state.

Keywords

• expansive soil
• coupled models
• saturated consolidation
• unsaturated consolidation