Compaction front and pore fluid pressurization in horizontally shaken drained granular layers

We numerically simulate a gently shaken fluid-saturated granular layer. Above a critical imposed acceleration an upward moving compaction front forms. The front divides the layer in two: above the front, a compacting fluidlike sublayer with a lithostatic pore pressure gradient (PPG), and under it, a compacted solidlike sublayer with a hydrostatic PPG. This front, and the controlling parameters of the coupled flow (permeability and fluid viscosity, rather than granular parameters), are theoretically predicted. These results can be inputs for saturated soil response to earthquake excitation.