DYNAMIC BEHAVIOR OF A POROELASTIC SLAB SUBJECTED TO UNIFORMLY DISTRIBUTED IMPULSIVE LOADING

This paper derives a complex dynamic modulus function for a poroelasti c slab with finite length and uses this to examine the range of validi ty of quasi-static solutions to Blot's dynamic poroelasticity equation s. It also examines the effects of side surfaces' boundary conditions on the solutions to the equations and presents systematic studies of t he effects of the slab length to thickness ratio and of the dissipatio n terms on the slab's storage and loss moduli. Blot's equations of por oelasticity are first phrased in terms of solid and fluid displacement s and then transformed into the Laplace domain. The Galerkin type fini te element method is used to solve these equations. Using quadrilatera l elements, the stiffness matrix for this method is then derived. The dynamic transfer functions are then obtained for the case of an impuls ive displacement applied to the top surface of the slab. Cases of both permeable and impermeable side surfaces are considered. The resulting solutions for the Laplace transform of the impulsive excitation respo nse are then transformed into frequency domain complex response functi ons, called complex dynamic modulus functions, which characterized the stiffness and damping of the slab. Parametric studies are then carrie d out employing the complex frequency response functions. (C) 1998 Els evier Science Ltd. All rights reserved.