Abstract
An absorbing boundary for saturated porous media is developed that can be used for transient analyses in the time domain. The elastic constitutive equations for the saturated porous media follow Bowen's formulation. The method consists of applying viscous tractions along the artificial boundary. The absorbing boundary behaviour is assumed linear and isotropic. Hadamard's conditions provide the speeds of the dilatational and shear waves that propagate in saturated porous media. Since these expressions are frequency independent, the intensities of the viscous tractions are evaluated in the time domain, and the two dilatational waves are accounted for. The viscous tractions are defined from the drained characteristics, assuming an infinite permeability, at variance with the traditional βundrainedβ method based on undrained characteristics and a null permeability. Solid media and materials with low permeability are also retrieved as subcases.
The results show that, at no additional cost, this βdrainedβ method is more accurate for all permeabilities than the βundrainedβ method, which disregards the existence of the second dilatational wave. Copyright Β© 2003 John Wiley & Sons, Ltd.