Torsional dynamic analysis of single piles by time-domain BEM

Abstract

The transient dynamic response of single piles in a layered half-space under a time-dependent torque is analyzed by a coupled FEM-BEM approach in which the pile is modelled by FEM and the half-space by a general cylindrical co-ordinates time-domain BEM. By virtue of the Fourier theory, only one-dimensional discretization is necessary for the boundaries of the three-dimensional layered half-space, while the pile shaft can be discretized as a one-dimensional elastic column member. The compatibility and equilibrium conditions between pile shaft and soil layers are employed to assemble the respective equations into one set. A comparison is carried out to demonstrate the accuracy of the approach. The influence of several parameters on the transient behavior of single piles is investigated through numerical examples. Of all the parameters, the shear modulus ratio Gp /Gs is found to be the most important governing factor. The other effective factors are the pile slenderness ratio l/r0, the soil layering and so on. © 1994 Academic Press. All rights reserved.