MOTION OF FOUNDATION ON A LAYERED SOIL MEDIUM .1. IMPEDANCE CHARACTERISTICS

An impedance matrix is derived for the relationship between displaceme nts and external excitations of a rigid or flexible foundation embedde d in a layered soil medium. The unknown contact distributed force betw een the foundation and soil is expanded in the frequency domain as a t wofold series of azimuthal and radial components; each term represents a basic or fundamental distribution. As a result, the total response of the soil, either of displacements or stresses, has the same type of series expression except for the fundamental distributions replaced b y influence functions. The coefficients of the series expansion, appea ring in both equilibrium conditions of the foundation and compatibilit y conditions on the contact surface, relate the foundation displacemen ts and excitations, and, therefore, result in the impedance matrix. Av oidance of integral equations in the soil-structure interaction analys is is the merit of the present approach. (C) 1997 Elsevier Science Lim ited.