Starting from the physical analysis of the deformation process of the rockfill dams, a viscous-elastic-plastic model is worked out, whose constitutive law reproduces the elastic-plastic as well as the rheological behavior. For the movement and stress analysis of the embankment dams, a solution technique is developed for using the new model within the finite element method. The algorithm is based on a step-by-step procedure, analytically simulating the construction sequences and dealing with the load increments apart from the time steps. The movement analysis based on the new model was performed for Lesu dam (h equals 60. 50m). The comparison of the measured and calculated movements indicates, by their good agreement, the performances of the model and the efficiency of the solution technique.