Communications on Hydraulic and Geotechnical Engineering: Liquefaction ofCohesive Sediments Caused by Waves

摘要

The objectives of this project were to study experimentally and to anlayze (1)the mechanisms underlying the generation of fluid mud due to waves, (2) the wave damping over a fluid-mud layer, and (3) the influence of a current on the transport of fluid mud. A review of mud properties is given in chapter 2: an introduction to clay mineralogy is given and the dominating processes are briefly discussed. Furthermore, different rheological models used in the literature to characterize mud suspensions are summarized. Chapter 3 is concerned with the generation of fluid mud. A review is given of the mechanisms, proposed in the literature, underlying the transition of a non-cohesive sediment from a quasi solid state to a fluid-like state due to wave action. The processes which seem to play a significant role in the phase transition of a cohesive sediment are also discussed. Some physico-chemical properties of the muds used in the experiments were determined for characterization. The basic determination procedure and the results of the measurements are presented in chapter 4. The rheological properties of these muds and the measurement procedure are also given. The wave/current flume, in which part of the experiments were carried out, is described in chapter 5. In chapter 6, the results of the flume experiments and some model results are presented. Experiments were also carried out in an oscillating-water tunnel. A description of this set-up as well as the experimental procedure are outlined in chapter 7. Finally, a summary and the main conclusions drawn from the results of this research are presented in chapter 8.