Dynamic stiffness of foundation embedded in layered halfspace based on wave propagation in cones

Abstract

SUMMARYThe dynamic sti ness of a foundation embedded in a multiple-layered halfspace is calculated postulating one-dimensional wave propagation in cone segments. In this strength-of-materials approach the sectional property of the cone segment increases in the direction of wave propagation. Re ections and refractions with waves propagating in corresponding cone segments occur at layer interfaces. Compared to rigorous procedures the novel method based on cone segments is easy to apply, provides conceptual clarity and physical insight in the wave propagation mechanisms.This method postulating one-dimensional wave propagation in cone segments with re ections and refractions at layer interfaces is evaluated, calculating the dynamic sti ness of a foundation embedded in a multiple-layered halfspace. For sites resting on a exible halfspace and ÿxed at the base, engineering accuracy (deviation of ±20%) is achieved for all degrees of freedom with a vast parameter variation. The behaviour below the cut-o frequency in an undamped site ÿxed at its base is also reliably predicted. The accuracy is, in general, better than for the method based on cone frustums, which can lead to negative damping.

Dynamic response of foundations on three-dimensional layered soil using the scaled boundary finite element method

“…The corresponding dynamic stiffness coefficients obtained using the thin layer method (see Ref. [13] in Ref. [13]) are also shown for comparison.…”

“…[13] in Ref. [13]) are also shown for comparison. Both examples demonstrate the accuracy and the correct implementation of the proposed method.…”

A practical method for estimating dynamic soil stiffness on surface of multi-layered soil

“…The same concept was investigated in Reference [9] in the frequency domain, but the wave propagation is considered and calculated in the time domain in this paper.…”

“…Meek and Wolf [5] and Wolf and Meek [6,7] expanded this method to an estimation method for the dynamic sti ness of the foundation on two-layered soil. They [8] applied this method to multi-layered soil, and Wolf and Preisig [9] modiÿed the method. However, the calculations of these methods are carried out in the frequency domain, so the transform to the time domain is the same problem as that seen above.…”

Calculation of impedances for axial symmetric foundation embedded in half-space medium using solutions for one layer stratum

“…Also, cone model was developed to calculate the dynamic response of a disk on surface of a soil layer resting on flexible rock subjected to harmonic excitations [8]. Furthermore, the concept of cone model was extended to calculate the dynamic stiffness for foundation embedded in a multiple-layered half-space [9].…”