FLAC3D analysis on soil moving through piles

Abstract

Piles may be utilised as deep foundations or employed to support offshore structures, which may be subjected to passive loading due to lateral soil movements. The safety of the piled foundations depends on the additional stresses induced. This issue has been investigated recently by conducting model tests on single piles and on pile groups with a new apparatus developed by the authors. Typical test results were analysed and reported previously. In this paper three-dimensional finite difference analyses are reported: (1) to predict the results of two model tests (with and without axial load); and (2) to investigate the effect of the moving and the stable depths of soil on the pile response. Typical results of the comparison between the FLAC3D analysis and the model tests for single piles in sand are presented in terms of three profiles namely: bending moment; shear force; and pile deflection profiles. A unique linear relationship between the maximum shear force (thrust) and the maximum bending moment induced on the piles is obtained regardless of the ratios of the moving depth over the stable depth.