Abstract
The stochastic finite element method is applied to study the effect of a spatially varying soil medium on the settlement of single-pile foundations. In this study, the soil medium is assumed to be linear-elastic, and it is modeled as a homogeneous random field. The random field captures the uncertainty in the soil modulus by means of the coefficient of variation and the scales of fluctuation. Using a first-order second-moment technique, the mean and coefficient of variation of the pile head settlement are determined. It is found that the uncertainty of the pile head settlement is dependent on both deterministic and stochastic parameters. Reliability analysis is then performed to compute the reliability index and the corresponding probability of unserviceable behavior. In order to facilitate the probabilistic design of pile foundations, the results of the analysis are presented in the form of concise charts suitable for use by practicing engineers.