On spatiotemporal wave–induced radiation distribution in a porous medium under impulsive transverse loadings

Abstract

Spatiotemporal wave–induced radiation pattern in a semi–infinite fluid filled porous medium to an impulsive transverse loading is investigated under imperfect surface hydraulic contacts. A surface stiffness parameter represents this fluid flow impedance cross the surface. It affects various wave mode radiations dependent on azimuth and depth. In the plane perpendicular (PSV) to the surface, all the wave modes are sensitive to surface stiffness, especially the R1 surface wave. A high surface stiffness can excite the R2 surface wave radiation and the energy redistributions. However, in the plane parallel (SH) to the surface, the SH wave shows no relationship to surface stiffness. Pore pressure polarizes in PSV plane. The R1 wave radiation in pore pressure corresponds to R1P2 transferring on the surface, not in accordance to displacement response. Furthermore, the surface stiffness dominates the fluid diffusivity near surface. For a leakage boundary, a pressure drop by local flow appears. The significant fluid resonance generates under the surface. The redistributed wave radiation in fluid may be a possible risk for near surface medium failure.