Limiting pressure on a laterally loaded pile in a frictional soil

Abstract

This letter investigates, by means of finite-difference analyses, the ultimate lateral pressure developed on a pile moving relative to a soil whose strength is characterised by an effective angle of shearing resistance φ′. Analyses were carried out to determine the distribution of ultimate pressure with depth, with particular attention paid to near-surface effects, for a value of φ′ representative of a clay soil. The model results are compared with common empirical distributions of ultimate lateral pressure, obtained generally from full-scale and model tests in sand. It was found that the depth to which the unconfined ground surface affects the ultimate lateral pressure developed is consistently about five pile diameters. Below the zone influenced by surface effects, limiting lateral pressures were found to increase linearly with depth. Commonly used empirical distributions for the limiting pressure were found to bracket the numerical results for a frictionless pile–soil interface and underestimate the numerical results for a full-strength pile–soil interface.