A Numerical Procedure to Simulate Particle Migration at the Contact Between Different Materials in Earthfill Dams

The control of the granulometric stability of a fine-grained material (B) requires a correctly designed protective granular material (T) whose voids, related to the grain size distribution (GSD) and porosity, must be small enough to stop the migrating particles of B within short distances (formation of “natural filter”), and simultaneously allow a safe drainage of B to prevent the occurrence of limit states (e.g. piping, clogging, blinding), inducing in turn uncontrolled increases of interstitial pressure. The available (empirical and analytical) methods to analyze particle migration phenomena at the contact between different materials generally don’t considerer the coupled effects of the involved geometrical and hydraulic variables (e.g. GSD, porosity, volume voids distribution, permeability, piezometric gradients, seepage velocity), as well as their progressive space-time evolution. Thus, a numerical procedure allowing to simulate coupled 1D seepage and particle migration processes, by taking into account both geometrical and hydraulic governing variables, as well as their mutual dependency, has been developed and applied to carry out a detailed analysis and review of some experimental data.