Averaged formulations of non-stationary problems for stratified porous media

The aim of this contribution is to investigate the length scale effect on the behaviour of periodically stratified saturated porous media, representing subsoils made of thin silt and clay layers or periodically reinforced soil structures. To this end two engineering models of a layered subsoil are formulated: the structural model, involving the thickness of the soil layering and the effective modulus model, where the layering thickness is scaled down. It is shown that in a description of non-stationary processes the length-scale effects play the crucial role and cannot be neglected.