Print Email Facebook Twitter A conceptual framework for shear flow–induced erosion of soft cohesive sediment beds Title A conceptual framework for shear flow–induced erosion of soft cohesive sediment beds Author Winterwerp, J.C. Van Kesteren, W.G.M. Van Prooijen, B.C. Jacobs, W. Faculty Civil Engineering and Geosciences Department Hydraulic Engineering Date 2012-10-24 Abstract This paper proposes a conceptual framework for erosion of cohesive sediment beds. We focus on cohesive beds, distinguishing between floc erosion, surface erosion, and mass erosion. By (our) definition, surface erosion is a drained soil mechanical process, whereas mass erosion occurs under undrained conditions. The eroding shear stress is modeled through a probability density function. This yields a continuous description of floc erosion and surface erosion as a function of mean bed shear stress. Furthermore, we assume a distribution for the bed strength. The mean values of the bed strength are derived from soil mechanical theory, assuming that the surface erosion rate is limited by the swelling rate from the undrained shear strength in the bed to its drained value at its surface. The rate of erosion then relates to the undrained shear strength of the soil, and its consolidation (swelling) coefficient. The critical shear stress for erosion is slightly larger than the true cohesion of the bed, i.e., the drained strength, and follows a power law relation with the plasticity index. The conceptual framework proposed herein has been validated against a limited number of experimental data, and has a series of advantages above other methods of direct measuring erodibility, as it is inexpensive and can be used to attain space-covering information on the sediment bed. Moreover, the use of bulk soil mechanical parameters accounts implicitly for the effects of organic material, though the role of, e.g., macrophytobenthos mats and/or bioturbation is difficult to capture a priori. Subject cohesive sedimenterosionsoil propertiesturbulence To reference this document use: http://resolver.tudelft.nl/uuid:294e3244-28d5-40b9-8c3a-030f36930231 DOI https://doi.org/10.1029/2012JC008072 Publisher American Geophysical Union Embargo date 2013-04-24 ISSN 0148-0227 Source Journal of Geophysical Research, 117 (C10), 2012 Part of collection Institutional Repository Document type journal article Rights © 2012 American Geophysical Union Files PDF 284768.pdf 891.92 KB Close viewer /islandora/object/uuid:294e3244-28d5-40b9-8c3a-030f36930231/datastream/OBJ/view