PILE BEHAVIOR - THEORY AND APPLICATION

This paper discusses the application of theory to the analysis of pile foundation behavior under axial loading. A classification system is suggested for pile analysis and design procedures, based on the rigour of the underlying theory. It is shown that a number of the analyses in use have a common underlying theoretical basis founded on the boundary element method and that such methods give solutions which are consistent with those from other methods such as the finite element method. The main characteristics of pile behavior are reviewed for single piles and pile groups subjected to static loading, cyclic loading, and to loading arising from externally-imposed soil movements. Correlations are then summarized for the geotechnical parameters required for the prediction of axial pile behavior. Using characteristic values of these parameters, design charts are developed for load capacity and settlement of piles and pile groups. Finally, three case studies are described which demonstrate the sensitivity of pile performance predictions to the method of analysis, the idealization of the soil profile, and the selection of soil parameters. It is shown that the method of analysis is likely to have less effect on the predicted performance than does the geotechnical characterization of the site.