In an effort to better assess the potential for sliding and liquefaction failure of earthen dams when subjected to earthquake loadings, a dynamic finite element approach focusing on these two failure mechanisms as well as on the vital role of the pore water pressure was undertaken. The constitutive response of the granular soil skeleton and its coupling with the fluid phase is formulated based on the Blot dynamic equations of motion. The constitutive model for the soil material was assumed to be linear with nonlinear terms included in the hysteretic damping terms. Despite the linear character of this theoretical model, one can still draw important conclusions regarding the stability and the liquefaction resistance of the cross-section. As an example, a hypothetical earth dam constructed over a saturated soil layer was considered. The steady state conditions of in-situ stress and pore pressure distributions in both the embankment and the foundation are evaluated and implemented in the stability and liquefaction criteria in conjunction with the dynamic analysis. The latter is carried out in the frequency domain and it reflects the response of the dam-foundation system to a seismic excitation. The computational aspect of the study is performed with finite element analysis. A transmitting boundary formulation for the two phase material was used to treat the infinite space problem. It is anticipated that the intensity of the earthquake input and certain soil properties have a profound effect on the failure susceptibility of the dam section. To address the uncertainties regarding the true values of such parameters, the analysis considered them parametrically
