Dynamic properties of earth-core Italian dams from field and laboratory tests

The seismic design of new earth-core dams as well as the seismic re-assessment of existing ones with advanced numerical simulations require the knowledge of dynamic properties of core materials in a wide range of shear strains. The key parameters to be determined are the shear wave velocity Vs (or the maximum shear modulus G0) and the normalized modulus reduction and damping ratio curves (G/G0-c and D-c). Indeed, limited data do exist in the scientific literature on the in-field measured Vs profiles and on the laboratory cyclic/dynamic tests on undisturbed core samples. In this paper the dynamic properties of core materials of six zoned Italian dams are described and the main peculiarities are discussed, also in the light of the dynamic behaviour of natural soils.