Vibrations in multilayered soils: A simplified and robust prediction equation

Abstract

Wave propagation in soil is controlled by both attenuation and amplification laws. The former is due to geometrical and material damping, while the latter is mainly due to velocity contrasts between the various layers and possibly some geometrical/topographic effects. In the field of seismology and earthquake engineering, several factors are considered to describe the site properties and predict the amplifications features, such as average velocity Vs30 and velocity-gradient-based coefficients. The reliability of these factors is questioned in the case of vibration problems, for which surface sources generated frequency components are much higher than in earthquake engineering. With this aim, considering various sites typologies, this paper suggests a set of relevant parameters for predicting vibration away from the vibratory source. Starting from numerical results (FEM), correlations between the proposed factors and the estimated displacements are discussed. These simple prediction equations are shown to be relevant and robust.