Publication

Abstract : This study develops a theoretical framework for shear-horizontal (SH) wave propagation generated by a point source in a fluid-saturated porous layer overlying a gradient porous half-space. The formulation employs Biot’s poroelastic theory extended to include spatially varying permeability and tortuosity in the lower half-space, thereby representing realistic heterogeneity. The governing equations of motion and fluid continuity are solved analytically using separation of variables, while boundary and interface continuity conditions are rigorously enforced to obtain a complex dispersion relation. The real and imaginary parts of this relation characterize the phase velocity and attenuation of SH waves, respectively. A numerical root-searching algorithm is implemented to extract physically admissible solutions over a range of non-dimensional frequencies, and parametric studies are performed to investigate the effects of gradient strength, layer thickness, and frequency on dispersive and damping behaviors. The results show strong agreement with existing analytical models and demonstrate enhanced predictive capability for graded porous systems. The proposed formulation extends classical poroelastic wave theories to heterogeneous media and provides valuable insights for subsurface characterization, seismic site response analysis, and poromechanical modeling of layered geomaterial.