Analysis of Laterally Loaded Piles in Sand Considering Scour Hole Dimensions

Scour is a process of soil erosion, which can occur around the foundations of bridges or offshore structures through the action of flowing water; it can, therefore, reduce the capacity of the foundations and sometimes lead to the failure of structures. During an analysis of scour effects on laterally loaded piles, scour hole geometry is often ignored. Instead, scour effects are considered by simply removing the whole soil layer to the scour depth. However, a scour hole has not only depth, but also width and a slope. At present, the widely used $p\text{-}y$ method for analyzing laterally loaded piles cannot consider three-dimensional scour hole dimensions. For this reason, a simplified method was developed herein for the analysis of laterally loaded piles in sand under a scour condition. The $p\text{-}y$ curves in this method were based on a wedge type of failure. The effects of the scour hole dimensions on the response of laterally loaded piles in sand were evaluated using this simplified method. The computed results from the simplified method compared well with those from the three-dimensional finite-difference method. Scour depth was identified as the most influential factor on the pile response compared with scour width and scour hole angle. Based on the parameters investigated, a model that removes the entire soil layer to the scour depth resulted in 49–68% higher groundline lateral displacements of the pile than a model that incorporates the three-dimensional scour hole dimensions.