Scour effects on lateral behavior of pile groups in sands

Abstract

Scour that removes soils around foundations supporting bridges and marine structures is the major cause for structural failures. Recently, many studies have been conducted to investigate scour effects on lateral behavior of single piles using numerical analyses, laboratory model tests, or centrifuge tests. However, very limited research is focused on scour effects on lateral behavior of pile groups. No simple method is currently available for practicing engineers to analyze pile groups under scour conditions. In this study, a simple and practical method was proposed based on the existing p-y curve theory to facilitate the design of laterally loaded pile groups under scour conditions. Feasibility of the proposed method was examined against 3D finite element (FE) analyses through a series of parametric studies by varying scour-hole dimensions, soil properties, and pile group configurations. The results showed that the proposed method generally produced agreeable results with the 3D FE analyses. Scour-induced lateral capacity loss of pile groups was 10–13% more in dense sands than in loose sands. Pile groups were more susceptible to scour than single piles under the equivalent scour conditions. A pile group with smaller pile spacing and larger pile numbers showed a less loss of lateral capacity due to scour.