Modeling rate-dependent behaviors of soft subsoil under embankment loads

The paper aims to model the rate-dependent behaviors of subsoil under embankment loads using a simple elasto-viscoplastic model, based on the modified Cam-clay model and Perzyna's overstress theory, coupled with Biot's consolidation theory. A geotextile reinforced embankment is studied. An inverse analysis procedure is proposed to identify the viscosity parameters of subsoil from the settlements due to the first few loading phases. In order to assess the performance of the proposed model, numerical predictions using the determined parameters are then compared with those obtained by four other models. Special attention is given to the effect of reinforcement on delayed deformations and on the stability of the embankments and foundations. The performance of the proposed inverse analysis procedure is also assessed. Finally, according to the simulation runs, it can be concluded that the proposed model is easy to be calibrated and suitable for geotechnical projects. The proposed model can describe the rate-dependent behaviors of soft soil compared with the modified Cam-clay model, with accuracy using the simple constitutive equations compared with other viscoplastic models.