Characterisation of internal erosion disturbances on sand/kaolinite samples
Résumé
Internal erosion is one of the main causes of instabilities within hydraulic earthstructures: dike, levee or dam. Entrainment and transport of some particles affect the porosity and grain size distribution, which change the hydraulic and mechanical characteristics. These evolutions could induce instabilities: slidings, overtoppings or even failures. The difficulty of detection and the great dynamic of internal erosion demonstrate the necessity of experimental studies from the beginning of particle transport. We propose a parametric study on sand-kaolinite samples. The follow up of the effluent is performed by an optical sensor and by weighing the amount of particles torn away from the sample. These tests show that the internal erosion is initiated by the displacement of clay particles. If sufficient kaolinite content is taken away, the erosion of sand particles is induced. The evolution of the solid mass sample loss depends on the values of the different parameters tested.