Nonlinear Biot waves in granular media

The nonlinear propagation through unconsolidated model granular media is investigated in the frame of the Biot-Allard theory extended to the case of a nonlinear quadratic behavior of the solid frame (the elastic beads and their contacts). We evaluate the importance of mode coupling between solid and fluid waves, depending on the actual fluid and the bead diameter. The application of these results to other media supporting Biot's waves (trabecular bones, porous ceramics, polymer foams ...) is straightforward, provided the parameters of the Biot-Allard model are available for these media.