Fine-tuning of the backward erosion piping model through small-scale, medium-scale and IJkdijk experiments

ABSTRACT A semi-theoretical model is available to estimate the effect of backward erosion piping by underseepage in a dike by computing the critical head. The model accounts for the groundwater flow through the subsoil, pipe flow through the erosion channel and a limited particle equilibrium at the bottom of the channel. This model is extended and updated with the results of a wide range of tests presented in the paper of (Van Beek et al., 2011). The small- scale tests are analyzed by means of a multivariate regression in order to identify the level of influence of each variable. The regression outcome for the permeability corresponds precisely with the outcome of the prediction rule. The effect of relative density, uniformity and particle roundness is empirically dealt with. The role of the particle size is adapted in the new empirical formulation.