Numerical study of uplift induced levee failure for the design of a centrifuge test

In geotechnical engineering, physical and numerical models seek to shed light on multiphase phenomena that threaten earth structure stability. This is the case of river levees: when subjected to non-ordinary hydraulic loads, local and global failures with consequent floods could occur. If, on one hand, centrifuge models can replicate the real phenomena, exploiting the enhanced gravity, while scaling geometrical features and time, on the other, numerical models extend the possible case studies by capturing key elements, governing the hydro-mechanical behaviour of the earthworks. However, the two techniques could complement and benefit each other. In this research, a potential failure mechanism, induced by the development of uplift pressures beneath the toe of a levee characterized by a peculiar stratigraphic profile, is investigated. The foundation consists of a shallow weak low-permeability layer, overlying a coarser and more permeable one, this latter acting as a hydraulic preferential flow path between riverside and landside. Results of a preliminary numerical study carried out with different methods are presented and discussed. The study aims to improve understanding of complex failure mechanisms and to encourage the development of more robust forecasting methods. Indeed the results have provided fundamental guidance for a centrifuge experimental set-up.