On incipient motion of silt-sand under combined action of waves and currents. (December 2017)

• Record Type: Journal Article
• Authors: Zuo, Liqin; Roelvink, Dano; Lu, Yongjun; Li, Shouqian
• Is Part Of: Applied ocean research. Volume 69(2017)
• Page Start: 116
• Page End: 125
• Publication Date: 2017-12
• Subjects: Threshold of sediment motion -- Silt -- Cohesive force -- Additional static water pressure -- Shields curve; Ocean engineering -- Periodicals; 620.416205
• DOI: 10.1016/j.apor.2017.10.005
• Languages: English
• ISSNs: 0141-1187

Abstract

Highlights: An expression of sediment incipient motion for silt-sand sediments under the combined wave and current conditions. The Shields number was revised by introducing the cohesive force and additional static water pressure. An extension of Shields curve. Abstract: Sediment incipient motion is a fundamental issue in sediment transport theory and engineering practice. Silt has transitional behavior between cohesive and non-cohesive sediment and its incipient motion is still poorly understood. This study aims to find an expression for incipient motion from silt to sand from a unified perspective and analysis. From the analysis of forces, using the derivation method for the Shields curve, an expression for sediment incipient motion is proposed for both silt and sand under conditions of combined waves and currents. The differences and similarities in the sediment motion threshold were analyzed under the effects of waves and currents, and fine and coarse sediment. The Shields number was revised by introducing the cohesive force and additional static water pressure, which indicates that this study could be seen as an extension of the Shields curve method for silt. A number of experimental datasets as well as field data were used to verify the formula. The effect of bulk density on fine sediment was discussed and tested using experimental data.