Experimental estimation of the nonlinear elastic parameters of dry and fluid-saturated porous media

The subject of study is nonlinear effects arising in dry and water saturate d grounds on irradiating the latter with biharmonic waves generated by both surface and borehole vibrators. The amplitudes of primary biharmonic and c ombination-frequency waves measured in boreholes show that the nonlinear pa rameter of a water-saturated ground is more than an order of magnitude grea ter than that of a dry ground of the same structure.