A PRECISE INTEGRATION APPROACH FOR THE DYNAMIC-STIFFNESS MATRIX OF STRIP FOOTINGS ON A LAYERED MEDIUM

A precise integration method (PIM) is applied to the evaluation of dynamic-stiffness matrix of strip footings on a layered medium. PIM is an efficient and accurate numerical method to study the wave motion in layered earth strata. Through Fourier transform, the governing equation of wave propagation is formulated in the frequency-wavenumber domain as a set of ordinary differential equations with two-point boundary value conditions, and the Green's functions are solved by PIM. Finally, the dynamic-stiffness matrix of rigid strip footing on layered medium is converted from frequency-wavenumber domain into frequency-spatial domain. The proposed algorithm has the advantages that it avoids the exponential overflow generally encountered in the case of transmission matrix. In addition, it is versatile and adaptable to various cases of footings. It ensures convergence at high-frequency range, while perfect accuracy can be achieved.