Analysis of the Behaviour of Piles Subjected to Torsion

摘要

Using a numerical method of analysis, based on integral equation techniques, Poulos (1975) presented charts of torsional flexibility of piles as a function of pile geometry and relative stiffness. In the present paper, an analysis is developed, based on a simple assumption concerning the stress field around a pile undergoing torsion, which leads to closed-form solutions for the torsional stiffness of a pile. Separate solutions are presented for the case of homogeneous soil (of constant stiffness) and for the case of soil where the stiffness is proportional to depth. It is shown how these separate solutions may be combined to cover more general variations of the soil stiffness with depth. The equations leading to the development of the analytical solutions may be used to investigate the effect of slip between pile and soil. In the final section of this paper, this approach is illustrated by a study of the results from torsion tests on full-scale piles.