Experimental evidence of wave-induced inhomogeneity in the strength of silty seabed sediments: Yellow River Delta, China

This paper presents the results of an experimental study in which the occurrence and evolution of inhomogeneity in the strength of a uniform-originated silty seabed were investigated. The pore pressure and penetration strength at different depths inside the seabed were observed during the experimental process under the weight of the soil and under the action of waves of different heights (H=5 cm, 10 cm, 15 cm). We found that a well-mixed silty seabed consolidates under the stress of its own weight, and its strength gradually increases as a result. Small wave action consolidates and strengthens the seabed and sediment. When the seabed is exposed to progressively higher waves, a fluidised response characterised by an arc-shaped boundary surface occurs on the seabed, and this response further controls the occurrence and evolution of the strength inhomogeneity of a uniform-origin seabed. The analyses clearly illustrate that features of seabed erosion and mass-transportation activity previously ascribed to increasing wave-current bed shear stress are controlled primarily by the process of wave-induced inhomogeneity in the strength of seabed sediments originating in the preceding period. In addition, the implications of the mechanism are explored. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.