Predicted and measured behaviour of an embankment on PVD-improved Ballina clay

Abstract

This paper presents Class-A and Class-C predictions of the behaviour of an embankment built on soft Ballina clay improved with prefabricated vertical drains. Predictions were carried out using hand calculations and the finite-difference method. The latter approach allowed the variation of soil parameters and stress levels with depth to be considered in the analyses. An alternative systematic procedure for estimating soil parameters based on high-quality laboratory data is described. Class-A predictions highlighted some disagreements with the measured total settlements and pore pressure dissipation rates. For Class-C predictions, the choice of geotechnical parameters used in the analyses was guided by a systematic assessment of the stress states undergone by soil elements underneath the embankment centreline. This led to a better agreement between predicted and measured data, which demonstrates the potential of the proposed procedure for future analyses of embankment behaviour on soft Ballina clay.