Numerical modelling of the resistance of the coarse sand barrier against backward erosion piping

Abstract

The coarse sand barrier (CSB) is a novel remediation measure to reinforce embankments against the internal erosion mechanism of backward erosion piping (BEP). The feasibility of the CSB is investigated in a research programme consisting of experiments at different scales, numerical analysis and application at a pilot site in the Netherlands. Laboratory experiments showed that the CSB increased the critical head drop for BEP by one order of magnitude. In this paper, the strength of the CSB is quantified using numerical modelling of the experiments. A local, scale-independent, strength criterion for the CSB is derived based on medium-scale experiments. The application of this local criterion is illustrated for a field-scale model, in which the critical head drop that can be retained increases by a factor two to three with the CSB.