Boundary conditions for the weak formulation of the mixed (u,p) poroelasticity problem

This paper presents the boundary conditions that apply to the-weak integral formulation of the Blot mixed (u,p) poroelasticity equations. These bounda ry conditions are derived from the classical boundary conditions of the Blo t displacement (u,U) poroelasticity equations. They are applied to the surf ace integrals of the associated weak form to account for, exterior excitati ons, supports, and couplings with exterior elastic, acoustic, poroelastic m edia, and a septum. It will be shown that the derived boundary conditions f or the (u,p) formulation lead to simpler finite element equations compared to those obtained from the (u,U) formulation. :Finally, two numerical examp les are presented to validate the poroelastic-septum coupling condition, an d to highlight the limitations of the free edge condition on a poroelastic medium. (C) 1999 Acoustical Society of America. [S0001-4966(99)04911-5].