Analytical closed-form solutions are developed for the elastic and elasto-plastic settlement of axially loaded piles in inhomogeneous soil. The soil is modelled by way of a bed of Winkler (‘t–z’) springs with stiffness varying as a power function of depth, described by two dimensionless inhomogeneity parameters. The associated governing differential equation is solved in an exact manner using Bessel functions, which reproduce the solution for homogeneous soil. Additional limiting cases are explored including: (a) infinitely long piles, (b) short piles, (c) perfectly floating piles and (d) perfectly end-bearing piles. The solution is extended to the non-linear range by employing elastic–perfectly plastic Winkler springs. A systematic approach for predicting the full load–settlement curve is presented and applied to tests from a site in London. Dimensionless charts are provided for routine design.

Geotechnical designers and modellers must capture and quantify the variability of key soil properties to make engineering decisions. There is a long history in geotechnical engineering of assembling large databases of past soil tests. This paper shows the use of geotechnical databases in two contexts: (a) slope stability modelling in the Eastern Caribbean and (b) settlement response of bored piles in London Clay.

Projects involving construction of piled foundations often rely on preliminary full-scale field tests to failure to predict performance under applied load. If these tests are not available, the ensuing uncertainty will naturally lead to conservative design assumptions. Such design assumptions will result in higher construction costs and often in longer construction times. This paper shows how a database of previous pile load tests can be used in conjunction with simple analytical tools to attempt a quantification of performance uncertainty. Data from a series of previously published axial load tests on piles in London Clay is employed to this end. The methodology developed in this paper can arguably be expanded to a wider range of test sites and geological materials.

Simplified methods for static and dynamic analysis of pile foundations under lateral loading are presented. Firstly, the classical model of a Beam on an elastic Winkler Foundation (BWF) and a number of formulas for the moduli of the associated springs and dashpots are briefly reviewed. This model (1) leads to a characteristic ("mechanical") pile length, encompassing both pile stiffness and slenderness, which has no counterpart in continuum formulations of the problem; (2) reduces the number of dimensionless groups governing the response, by one. Secondly, solutions for stiffness of single piles are derived for both homogeneous and inhomogeneous soil conditions. These solutions are based on energy principles obtained using complex-valued shape functions analogous to those used in spectral finite-element methods, which account for phase differences in the response at different elevations down the pile. Use of these functions over existing formulations based on real-valued (static) shape functions, greatly improves the accuracy of the solution in the dynamic regime. It is also shown that the exponents in monomial expressions for the static stiffness of long piles, are constrained by a condition associated with the static condensation of the stiffness matrix, and that this condition is not satisfied in a number of formulae in literature. Thirdly, solutions for grouped piles are derived using the superposition approach of Poulos. To this end, a family of interaction factors accounting for pile-soil-pile interaction is reviewed. Results are presented in the form of dimensionless graphs and charts that elucidate critical aspects of the problem. Detailed comparisons with more rigorous numerical continuum solutions are provided.Author Version on bridge piers, machine vibrations, wind and blasts. The problem has been thoroughly investigated for more than 70 years and valuable knowledge has been acquired as to the physics of the response and solution methods.Analysis approaches for laterally-loaded piles can be roughly classified into the following three main groups: (A) Rigorous numerical methods, mainly finite-element and boundary-element formulations which treat the soil around and underneath the pile as a continuum. Specifically:-Finite-Element Methods (FEM) are general-purpose continuum formulations capable of handling a wide range of pile-related problems including elastic analyses (Blaney et al.