Dynamic axial load transfer from elastic bar to poroelastic medium

The time-harmonic response of a cylindrical elastic bar (pile) partially em bedded in a homogeneous poroelastic medium and subjected to a vertical load is considered. The bar is modeled using 1D elastic theory valid for long b ars in the low-frequency range, and the porous medium using Blot's 3D elast odynamic theory. The bar is bonded to the surrounding medium along the cont act surface. The problem is formulated by decomposing the bar/porous medium system into a fictitious bar and an extended porous medium. A Fredholm's i ntegral equation of the second kind governs the distribution of axial force in the fictitious bar. The integral equation involves kernels that are dis placement and strain influence functions of a poroelastic half-space subjec ted to a buried, uniform vertical patch load. The governing integral equati on is solved by applying numerical quadrature. The solutions for axial disp lacement and axial force of the bar, and the pore pressure are also derived . Selected numerical results for vertical impedance, axial force, and pore pressure profiles are presented to portray the influence of bar stiffness a nd length/radius ratio, frequency of excitation, and poroelastic properties .