Dynamic Response of Borehole in Poroelastic Medium with Disturbed Zone

Dynamic response of an infinite cylindrical borehole in a poroelastic medium with an excavation disturbed zone is investigated in this paper. The borehole is subjected to axisymmetric time-harmonic loads and fluid sources applied to its surface, which is either fully permeable or impermeable. The governing equations based on Biot's poroelastodynamics theory are solved by using two scalar potentials and two vector potentials. The general solutions are then derived through the application of Fourier integral transform with respect to the vertical coordinate. An exact stiffness matrix scheme is established from the derived general solutions to include the excavation disturbed zone. Boundary value problems corresponding to a borehole with the disturbed zone subjected to axisymmetric loads and fluid sources are formulated, and selected numerical results are presented to portray dynamic response of a borehole in a poroelastic medium with consideration of excavation disturbed zone.