Kinematic analysis of pile in anisotropic poroelastic soil subjected to vertical incident S-waves

: Anisotropic poroelastic media are comprehensively present in nature, exhibiting mechanical properties distinctly different from purely elastic media, primarily attributed to the coupled fluid-solid interactions within their porous microstructure. A novel model is developed for analyzing the kinematic characteristics of an end-bearing pile interacting with the surrounding anisotropic poroelastic soil under vertically incident shear waves. The surrounding soil is characterized as a transversely isotropic poroelastic medium following Biot's poroelastodynamic theory, while the embedded pile is assumed to comply with the Euler-Bernoulli beam theory. The problem is solved by combining the free- and scattered-field motions of the anisotropic poroelastic medium with the dynamic equilibrium equation of the pile. Model verification is conducted through comparison with existing results. Numerical examples unveil that soil anisotropy and pile slenderness ratio significantly influence the translational and rotational kinematic response factors of the pile, as well as the deformation distribution along the pile. Within a certain frequency range, the impact of the bulk modulus of pore fluid and soil permeability on the field quantities is also observed, along with the influencing mechanism of anisotropic parameters and pile slenderness ratio on the amplification/attenuation of the free-field lateral soil displacement in the r - z plane.