ABSTRACT
We investigate the mechanical instability of soil and subsequent destabilization of the ground resulting from piping. We aim to throw light upon the processes of piping failure and ground depression from the particle (micro) level to the soil system (macro) level in river levees using DEM and continuum modelling and Smoothed Particle Hydrodynamics (SPH). Simulations of local seepage failure and internal erosion show the success of this micromechanics approach. From simulation results, when no internal erosion has occurred and the leaked water was clean, the toe slope of the levee becomes swollen and loose, but the levee did not result in a break. When internal erosion and localized water flow with sand volcano have occurred and the leaked water was muddy, then local deformation of the toe slope progresses, and the levee became instable and collapsed.
The simulation scheme proposed in this paper showed the success of this micromechanics approach of progressive seepage failure with internal erosion. Under these conditions, when the intensity of the levee body (the cohesive strength) differs, the sites where a foundation slips or cracks will differ.
As a result, the amount of levee damage will differ. In other words, the morphology and degree of damage differ according to the combination of characteristics of the foundation and the levee body, which in turn affects the location of the weak point of the levee. Moreover, the place where the deformation starts can be quite different from the place where large deformation occurs in the end.
