Axisymmetric transient response of a cylindrical cavity in an unsaturated poroelastic medium

Abstract

In this study, the transient response of an infinite unsaturated poroelastic medium with an infinitely long uniform cylindrical cavity subjected to axially symmetric transient radial tractions is investigated. Using the Laplace transform, analytical solutions are obtained for three different types of prescribed transient radial pressures (step, gradually applied step, and triangular pulse loads) acting on the surface of a permeable cavity and that of an impermeable cavity. The time histories of the radial displacement, stresses, pore pressure, and discharge are derived by inverting the Laplace domain solutions using a reliable numerical scheme. The solution can be simplified to one in which the infinite medium is assumed to be a saturated poroelastic medium. The validity of the solution was confirmed by comparison with COMSOL numerical solutions. A detailed parametric study is presented to illustrate the influence of the saturation of the unsaturated poroelastic medium on the response of the radial displacement, hoop stress, and pore fluid pressure at the cavity surface under different boundary conditions.