ABSTRACT
Experimental evidence shows that soils subjected to dynamic excitations have both the ability to store and to dissipate strain energy. The phenomenon of energy dissipation takes place even at very small strain levels, below the linear cyclic threshold shear strain. From a phenomenological point of view this type of material behaviour can conveniently be described by the linear theory of viscoelasticity. An important result predicted by this theory is the functional dependence between the velocity of the propagation of body waves and the material damping ratio. Hence, in contrast to usual practice, these parameters should be measured simultaneously and at the same frequency of excitation. In this article the authors present a new experimental procedure to be conducted in laboratory with resonant column apparatus where the shear wave velocity and the shear damping ratio are measured simultaneously. Since these parameters are determined at specific frequencies of excitation, the method is also well suited to investigate the frequency dependence laws of these important soil parameters.
