Settlements of Embankments in Soft Soils

Abstract

The major part of this paper is on the challenges in predicting settlements in highway embankments and reclamation works in marine, deltaic and estuarine type of deposits. The emphasis is on practical aspects and the difficulties experienced in confidently estimating settlements even after a century of developments and contributions. The influence of the general geology and soil conditions is discussed in relation to the site investigation works and the establishment of soil profile models. The fundamentals of preloading techniques with and without prefabricated drains (PVD) as ground improvement measures are also included. The observational approach in evaluating PVD performance and settlement estimations is then made with emphasis on curtailing residual settlements. Finally, the latter part of the paper is devoted to the analytical and numerical solutions of the behaviour of piled supported approach embankments with transfer layers. Geogrid reinforced pile supported (GRPS) embankment system is studied with the analytical approaches of Terzaghi, BS8006 method and Hewlett and Randolph method. Additionally, numerical analyses are also made with the Plaxis software.