Impact of loosely bounded interfaces between three-layered media on shear wave propagation

This study is mainly focused on the behavior change of shear waves. These waves propagate through an inhomogeneous sandwiched water-saturated porous layer in between inhomogeneous elastic layer and inhomogeneous sandy half space under the assumption of non-local theory. Different types of inhomogeneities based on the depth of the layers have been considered in terms of elastic moduli and densities of the medium. Due to the availability of fluid in the second layer, we consider loose bonding at the interfaces in between these three layers, as fluid movement through the interfaces may be possible. A complex dispersion equation has been derived with respect to the boundary conditions. Real and imaginary parts of the dispersion equation provide us with the phase velocity of shear wave and dissipation due to loose bonding at the interfaces, respectively. This dispersion equation has been solved numerically with the help of Newton Raphson method. For validation of the present problem, the numerical solution of dispersion equation has been depicted here graphically in terms of phase velocity ( c/c_2) of shear wave vs. non-dimensional wave number kH_1 (where k is the wave number and H_1 is the thickness of the second porous layer). Also, we discuss about the impact of depth ratios, inhomogeneity of the medium, non-local parameters, loose bonding, and porosity of the sandwiched layer on the propagation of the shear wave.