CONVECTION AND DIFFUSION IN AN EMBANKMENT UNDER SLOW CYCLIC DEFORMATION

We demonstrate that a spontaneous convection flow is generated in a gr anular material submitted to a cyclic bull-dozing effect. A diffusion process is superimposed on the convection so that the right descriptio n needs at least a bias diffusion formalism. This means in particular that two neighbouring grains at some time may become wide apart after a while. We give an example of convection. We show that these results are compatible with classical soil mechanics and we interpret these ph enomena within this scheme, using both a finite element technique and yield design theory.