Influence of using a creep, rate, or an elastoplastic model for predicting the behaviour of embankments on soft soils

Abstract

The predictability of the behaviour of an embankment constructed on a soft soil with three types of fully coupled finite element analysis models; namely a rate-formulated elasto-viscoplastic, a creep-formulated elasto-viscoplastic, and modified Cam clay (MCC) elastoplastic material model for the foundation soil is examined in this paper. The well documented geotextile reinforced Sackville test embankment was chosen for analyses using the three finite element models. Details of the analyses carried out using the three models and the results are discussed in comparison with field performance. All three models were found to be capable of predicting the behaviour of this embankment reasonably well. The creep model gave slightly better overall predictions of the behaviour compared to the rate and MCC models and therefore is considered to be better for predicting the time-dependent behaviour of this embankment. However, it requires the coefficient of secondary compression of the foundation soft soil as an additional input parameter and consumes more computing resources and time. In contrast, this study suggests that the MCC model is also capable of giving reasonably good overall predictions using less computing resources and time and therefore is sufficient for predicting the performance of embankments on soft soils.Key words: embankment, soft soil, geosynthetic reinforcement, analysis, viscoplasticity, creep.