Application of an Innovative Displacement Based Design Approach for Earth Embankments on Piled Foundations

Deep foundations are commonly employed as settlement reducers for earth embankments on soft soil layers. Owing to the presence of piles, both stresses transmitted to the foundation soil and average settlements reduce. Since the piles may be interpreted as a vertical heterogeneity for the system, during the embankment construction and the soil consolidation, differential settlements accumulate at both the base and the top of the embankment. This complex interaction mechanism is severely influenced by the embankment height and by the relative stiffness of the various elements constituting this peculiar geostructure. Nevertheless, the approaches commonly adopted in the current engineering practice and the ones suggested by design codes do not explicitly consider the material deformability and do not allow the embankment settlement estimation. In this paper, the practical application of a new displacement based design approach for earth embankment on piled foundations under drained condition is presented. This model, based on the concept of “plane of equal settlement”, explicitly puts in relationship the embankment height, interpreted as a generalized loading variable, and the settlements at the top of the embankment.