A soil element is often modeled as a lumped mass and the Voigt model, which consists of a spring and a dashpot. As for the damping characteristic, the Rayleigh damping is used. But there are few studies in which the applicability of Rayleigh damping to non-linear analyses of soil layer has been examined. In this study, therefore, we examine the effect of the Rayleigh damping in the non-linear response of soil layer from the viewpoint of wave propagation caused by the dashpot (the Rayleigh damping). As a result, it is found that the wave propagation by the shear force of soil element is reduced by its non-linearity of relationship, but the wave propagation by the dashpot becomes larger relatively. At a stratum boundary where the impedance ratio is large, in particular, the wave propagation with a large amplitude is generated. Then, an excessive force (wave propagation) will be transmitted to the upper layer from the lower layer and a large shear strain will be caused in the upper layer.

Copyright (c) 2001 Railway Technical Research Institute