Backward Erosion Piping Model Verification Using Cases in China and The Netherlands

Backward erosion piping, the process of shallow pipe development in the sandy foundation of levees, is a threat to the safety of levees in countries like China and the Netherlands. Several models are available to predict the required critical head for this phenomenon, i.e. Bligh’s model and Sellmeijer’s model. Well-documented breach cases, which unfortunately are rare, give the opportunity to verify the applicability of prediction models. In this paper two piping cases in China and one piping case in the Netherlands have been described and analyzed in order to compare the outcome of prediction models with this actual data. It is concluded that Bligh’s model is easy to apply due to a small number of input parameters. The use of this model as a first step in safety assessment is limited due to the fact that it can give lower critical head predictions than the more accurate Sellmeijer model. On the other hand, the Sellmeijer model is more difficult to apply due to its sensitivity to permeability and grain size parameters. This sensitively results in a wide range for the critical head due to large uncertainties in the parameters. A probabilistic approach for parameter estimation combined with a more detailed soil investigation where necessary is recommended for a more accurate piping prediction