A finite element approach for dynamic seepage flows

A finite element approach for the dynamic analysis of seepage flows is presented that represents the first step of a study on the effects of earthquakes on retaining or embedded structures in saturated granular soils. The equations governing the flow of a liquid within a porous skeleton under an acceleration field varying with time are recalled first. Then they are combined in a differential equation that, reduced in its weak form, leads to a finite formulation of the problem in term of discharge velocity only. This first approach shows some stability problem during the time integration process unless exceedingly small time increments are adopted. To overcome this drawback two alternative formulations, involving different sets of free variables, are out-lined and commented upon