A STUDY ON SEDIMENT SUSPENSIONS NEAR A WAVE-FLUIDIZED FINE SANDY SEABED

摘要

In this paper, a series of wave flume tests on wave-induced seabed responses of a fine sandy soil (d_(50)= 0.069 mm) were conducted to investigate near bed sediment suspension upon fluidization. One sediment suspension-concentration probe and several pore pressure transducers were deployed few centimeters above and at different depths inside the test soils for simultaneous measurements under monochromatic wave actions. The measurements display that the mean values of suspended sediment concentration start to increase at about several wave cycles after the set-off of soil fluidization with significant pore pressure build-ups in the test sandy soil. Under continuous wave actions upon the fluidized soils, suspended sediment concentrations used to increase to a maximum and then decrease slowly. In the following runs of wave actions with similar heights and periods, thickness of fluidized seabed generally reduces while the maximum suspended sediment concentration drops off as well. These results were always confirmed with clear observations of sediment pluming events over the fluidized beds.