Internal erosion of earth structures as a coupled hydromechanical process

The present paper describes a model of internal erosion of earth structures based on rigorous thermodynamic principles and the theory of porous media. The focus is concerned with the initial stage of internal erosion, prior to the formation of macroscopic channels, whenthe continuum approach is applicable. The soil skeleton saturated by a pore fluid is treated as the superposition of 3 continua in interaction;the pore fluid itself consists of a mixture of water and eroded particles. The erosion kinetics is based on the shear stress developed at the solid-fluid interface. The applicability of the model is illustrated by a finite element simulation. The simulations show how the phenomenon of piping preferentially arises in regions where hydraulic gradients are critical. Effects of mechanical degradations due to internal erosion are demonstrated.