Finite Element Analysis of Internal Erosion Effect on the Stability of Dikes

In the present study, a numerical solution is proposed in order to quantify the impact of internal erosion on dike stability. The mathematical model, consisting of erosion equations, mixture flow equations and stress equilibrium equations, is solved numerically by the finite element method using COMSOL Multiphysics. The shear strength reduction technique is used to analyze the stability of a dike taking into account the effect of internal erosion. The variation in time and space of porosity as a consequence of internal erosion is chosen as the coupling parameter. Soil stiffness and strength are made dependent on porosity, with the material becoming weaker as porosity increases. The results show that the porosity increases significantly at the dike toe, which was explained by an erosion of this zone. Erosion at the dike toe induces alterations in the mechanical response of the medium. Since the soil strength decreases at increasing porosity, the factor of safety of the downstream slope undergoes significant reduction. This study may help to better understand how internal erosion affects embankments performance, and to better prevent instability of hydraulic structures.