Initiation of Motion for Sand-Mud Bed Types

Abstract The initiation of motion of sand-mud bed mixtures remains inadequately understood and not accurately predicted. This study sought to compare and analyze the methodology and results of different sand-mud erosion experiments. Data from different erosion experiments were combined to create a dataset of varying sand-mud combinations with an emphasis on varying clay-silt ratios. The framework proposed by Van Ledden [1] was used to separate the data into six different bed types. These bed types are characterized by their cohesive property and network structure. The cohesive property is based on the mass fraction of clay and the network structure is based on the dominant sediment fraction. The different bed types demonstrated different ranges of critical bed shear stress for various ranges of median grain size or mass fraction of mud. This indicates that distinct initiation of motion mechanisms are dominant in different bed types.