Hydro-mechanical modeling of internal erosion in dike

Instability in geotechnical structures such as dikes or earth dams may be induced by internal erosion. In this phenomenon, finer soil particles are plucked off from the solid matrix by seepage flow and transported through the pore domain over time. Due to the loss of a part of the solid phase, the mechanical properties of the soil are progressively degraded, and, with time, earthen structures are under considerable risk of failure. Research on this topic is still fairly new and much more needs to be understood. In this study, a hydro-mechanical model based on porous continuous medium theory has been proposed to assess how internal erosion impacts the safety of earthen structures. An elasto-plastic constitutive model for sand-silt mixtures has been developed to describe the effect of the evolution of both porosity and fines content induced by internal erosion upon the behavior of the soil skeleton. The model is developed within finite element method framework. It is applied to a dike subjected to internal erosion induced by the presence of a karstic cavity beneath the alluvium layer.