Abstract: It is inconvenient for research the deformation mechanism of materials for earth-rock dam under dynamic loading using equivalent linear viscoelastic model, though it has been applied widely, because the stress-strain expressions haven’t been derived in this model and the energy dissipation don’t be described. In this paper, the Ramberg-Osgood constitutive model with variable parameters has been researched; and its adaptability has been discussed. It is found that the Ramberg-Osgood constitutive model is not applicable for describing the dynamic property of soil in small strain level. Also the expression of variable parameters is derived; the hysteretic loops have been drawn in different dynamic shear levels. A solid foundation has been established for studying the dynamic dissipation and strain mechanism of earth-rock dam materials.

Key words: earth-rock dam materials, Ramberg-Osgood constitutive model with variable parameters, hysteretic loop