Experimental study on the siltation of high-pile wharves considering pile groups and berthing ships

• A large-scale flume experiment on siltation of high-pile wharves was conducted. • The flow-blocking effect induced sediment deposition beneath high-pile wharves was investigated. • A formula for siltation intensity beneath the high-pile wharves incorporating pile-group effects was developed. Sediment siltation around high-pile wharves, occurring in front of, beneath, and behind the structure, significantly alters the loading distribution and affects the overall safety of the wharf. A series of large-scale physical model experiments for the sediment transport around high-pile wharves have been conducted in a current-wave basin. The effects of the suspended sediment concentration, flow velocity, flow direction, and ship berthing conditions on siltation around high-pile wharves are systematically investigated. Due to the flow-blocking effect of the pile groups, the velocity beneath the piles decreases significantly, leading to prominent sediment siltation around the pile foundations. The results demonstrate that siltation beneath the wharf is most pronounced during ebb tide compared to flood tide, under similar flow velocity conditions. When comparing steady flow and tidal current conditions, the siltation depth under tidal currents is higher than that under steady flow, and the spatial distribution of siltation also differs. Additionally, an increase in the suspended sediment concentration leads to a corresponding increase in depth of siltation beneath the wharf. This study also demonstrates that ship berthing alters local hydrodynamic conditions, leading to flow reduction and siltation increasing. The influence of ship-induced siltation is primarily confined to areas adjacent to the berthing location. Furthermore, this study successfully derived a refined formula for predicting siltation intensity. It offers a reliable tool for sedimentation prediction behind pile-supported wharves on muddy coasts.