Dynamic-Stiffness Coefficients And Dynamic Response Of Embedded Foundations

The analysis of dynamic-stiffness coefficients of embedded foundations and the foundation response under the action of the seismic excitation are important both in theory and engineering. Wolf derived dynamic-stiffness matrix of elastic layered soil, which formed a complete theory for wave propagation in layered site and dynamic soil-structure interaction. How to use Wolf's theory to calculate dynamic-stiffness coefficients of embedded foundations and the foundation response under the action of the seismic excitation will be mainly resolved in this paper.General solutions of the wave equations are deduced by introducing wave potentials. Then exact and symmetric dynamic-stiffness matrices of a layered soil and half-space are derived. All parameters have explicitly physical meaning and the thickness o sub-layers has no influence on the calculation precision, which is very convenient to engineering application. Based on these matrices, Green's functions are derived for distributed loads acting on inclined line in a layered site, which resolved the key problems in the calculation of dynamic-stiffness coefficients of embedded foundations by using the indirect boundary element method.The dynamic-stiffness coefficients of embedded foundations on half-space and layered site is systematically calculated and researched. The dynamic-stiffness coefficients of embedded foundations under different embedment is discussed.After calculating dynamic-stiffness coefficients and considering the mass of the foundation and the structure, foundation response under the action of the seismic excitation is systematically researched. The influence of embedment on the foundation response is emphatically analysed.