Probabilistic analysis of top deflection of laterally loaded piles considering spatially variable soil stiffness

Pile foundations represent one of the most prevalent foundation types utilized in offshore geotechnical engineering for deep foundations. For the laterally loaded piles which primarily experience bending deformation, engineers are mainly concerned about the characteristics of the pile top deflection under the action of lateral load during the service period. Due to the spatial variability of soil properties, the pile top deflection may still exceed the design maximum allowable deflection under the requirements of Serviceability Limit State (SLS), and the probabilistic approach can address this issue. This paper investigates the failure probability of a single pile’s top deflection in consideration of the spatial variability of soil lateral stiffness. Using the random finite element method (RFEM), the statistical characteristics of the pile top deflection under different degrees of soil stiffness variability are analyzed. Based on the local average theory, an approximate analytical method is proposed. This method is verified by the Monte Carlo simulation (MCS) results of random finite element analysis. The results demonstrate that the analytical method can accurately predict the statistical characteristics and failure probability of the pile top deflection. It offers an alternative to the complicated Monte Carlo simulations, and provides a convenient tool for estimating the failure probability of pile top deflection for laterally loaded piles.