Synopsis The response of rigid and compressible single piles embedded in a homogeneous isotropic linear elastic medium has been obtained by a rigorous analysis based on Mindlin's solutions for a po...

The Elastic Analysis of Compressible Piles and Pile Groups

The main objective of this work is to examine the effect of nonlinear soil behavior on the axial and lateral response of piles to monotonic and cyclic loading with a view towards developing simplified, yet realistic models for representing pile‐soil‐pile interaction effects. The specific role of pile‐soil slippage and separation, and the overall nonlinear soil behavior on the response of single piles and pairs of piles is studied by means of a three‐dimensional finite element elastoplastic model that includes interface elements for representing slippage and pile‐soil separation. Numerical results indicate that material nonlinearity can significantly affect pile and soil response. Pile‐soil slippage is dominant under purely axial loading, while for lateral loads pile‐soil separation and generalized inelastic soil deformation are the crucial factors. In fact, ignoring these sources of nonlinearity can lead to greatly overestimating the amount of interaction between piles. Guided by the results of this work,...

Three-dimensional nonlinear study of piles

Deformation analysis of soft ground reinforced by columnar inclusions

Synopsis The Paper presents an elastic analysis of two problems concerning the interaction with the supporting ground of an arbitrarily spaced group of piles, embedded in a smooth ground contacting pile cap of any shape, namely the load displacement behaviour of the system and the load distribution between the piles in the group and the cap. The problems are formulated as an integral equation developed from Mindlin's analysis for a point load embedded within a semi-infinite ideal elastic half space. The effect on the response of the system of the pile length to diameter ratio, pile cap size and the compressibility ratio of the pile and supporting medium has been investigated and specific results are presented graphically for a single pile with a square cap and typical pile groups in square and rectangular arrays. La Communication presente une analyse elastique de deux problemes portant sur l'interaction, avec le sol de support, d'un groupe de pieux places arbitrairement, loges dans le sol et en contact av...

The problem of pile group-pile cap interaction

This Paper describes a series of tests made on instrumented tubular steel piles in the field to examine the mechanism of load transfer from piles in stiff clay. The piles were jacked into the ground and during installation detailed measurements were made of the vertical movements of the soil near the ground surface and at mid-pile level and of the distribution of load in the pile shafts. During installation of the first pile, loading tests were made at a range of penetrations so that the variation of the soil properties with depth and the effect of pile length on the settlements at corresponding working loads could be examined. The movements of piles already installed and changes in their residual shaft loading were observed as subsequent piles were driven. The main part of the study was a detailed examination of the soil displacements around and beneath a pile under working load conditions using new instrumentation developed for this purpose. By relating the soil displacements to the pile settlement and ...

Jacked piles in London Clay: a study of load transfer and settlement under working conditions

The settlement behavior of a single compressible floating pile is analyzed and influence factors are presented for the settlement for a wide range of values of length-to-diameter ratio L/d and pile stiffness factor K , a measure of the relative compressibility of the pile and, for a solid pile, the ratio of the Young's moduli of the pile and the soil. The value of K markedly affects the settlement and the shear stress distribution along the pile and has a considerable influence on the load-settlement behavior of a pile loaded to failure in a saturated clay under undrained conditions. However, the ratio of the immediate to the total final settlement is only slightly affected by K while the settlement reduction due to an enlarged pile base is almost independent of K . The value of K at which the pile behaves as an incompressible pile (for which K = [infinity]) increases as L/d increases. Comparisons between the theoretical behavior of a pile and that reported from field measurements of piles in clay show encouraging agreement.

Neli S. Mattes

Papers

Settlement of Single Compressible Pile