The paper presents results of studies on the dynamic behavior and stress-strain state of high earth dams with allowance for non-linearly viscoelastic properties of soil, large strains and heterogeneous features of a structure. The studies consider the effect of non-linearly viscoelastic properties of soil, large strains, heterogeneous character of a structure and geometrical parameters of a structure on the change of the stress-strain state of earth dams in pre-resonant, resonant and post-resonant modes of structure oscillations. As a result, some mechanical effects, occurring with allowance for the discussed factors in a dynamic mode of the structure operation, have been revealed. Consideration of large strains and heterogeneity of the structure leads to strengthening a stress jump between heterogeneous parts of the structure; consideration of non-linearly viscoelastic properties of the structure material in a resonant mode of oscillations decreases singnificantly the amplitude of displacements and amplitudes of stress intensity in dangerous (related to strength) points of a dam, comparing with a linearly elastic case.