DYNAMIC STIFFNESS OF FOUNDATION ON LAYERED SOIL HALF-SPACE USING CONEFRUSTUMS

Approximate dynamic-stiffness coefficients of a disk on the surface of a single layer on a half-space may be calculated using cone models. T his concept is generalized to the case of a horzontally stratified sit e consisting of many layers on a homogeneous half-space. After constru cting the so-called 'backbone cone' determining the radii of the disks at all interfaces, the dynamic-stiffness matrices of the layers (mode lled as cone frustums) and the dynamic-stiffness coefficient of the un derlying half-space (modelled as a cone) are assembled to that of the site. The dynamic-stiffness matric of a layer is a complex-valued func tion of frequency because radiation of energy in the horizontal direct ion is considered. In this model of the layered half-space the propert ies of the cone reproduce themselves (cloning). The advantages of usin g cone models are also present for the layered half-space; in particul ar, no transformation to the wave-number domain is performed.