Engineers Australia

Effects of internal stress state on performance of embankments on soft soils

Behzad Fatahi, Thu Minh Le and Hadi Khabbaz


Analysing the behaviour of soft soil under embankment loads is a challenging task for geotechnical engineers. This numerical study revisits the case study of an embankment constructed on Boston Blue Clay, considering the model incorporating the influence of soil creep on the ground lateral deformation and pore water pressure. Then a numerical parametric study is conducted to investigate the influence of the lateral earth pressure coefficient at rest (K0) calculated based on the different available correlations on the vertical and horizontal displacements, pore water pressures, and the factor of safety of the embankment. The results indicate that although the value of K0 influences the predicted horizontal and vertical displacements notably, it has minor effects on the predicted pore water pressures. The lateral earth pressure coefficient influences the long term stability of the embankment and thus the effects of the initial stress field on the stability of embankments should be taken into consideration, while assessing the performance of embankments constructed on soft soils. It is recommended to determine the in situ horizontal stresses using accurate methods such as self-boring pressuremeter to predict the behaviour of embankments on the soft ground precisely