Numerical study of large deformation and buoyancy effects on consolidation settlement in embankment construction

Prediction of consolidation settlement in soft soils is a challenge for practising engineers. The use of simple modelling techniques without considering the large deformation and buoyancy effects results in the overprediction of settlement. This chapter presents a comparison study between small deformation analysis and large deformation analysis with and without buoyancy effect. A two-dimensional plane strain model was used to simulate an embankment constructed over soft deposits. The numerical results showed a maximum of 44% overprediction could happen if neither effect was taken into account. The study also examined the effects of key parameters such as compression ratio, soft soil thickness and fill height on the settlement performance when large strain and buoyancy are considered. Generally, the greater the value of parameters, the greater the effect of large deformation compared to the small deformation analysis. The numerical results were compared with 1D consolidation theory for small deformation and existing solutions for the buoyancy effect. The numerical results matched well with the 1D consolidation theory for small deformation analyses, while reasonable agreements were obtained for cases with buoyancy effects being considered.