Author(s): Hanbin Gu; Yanbao Li; Huaxing Zhou; Jingshi Sun; Wei Zhang
Linked Author(s): Wei Zhang
Keywords: Current; Sediment; Erosion of seabed; Yangtse River estuary
Abstract: To cooperate the mound structure design in the deep channel of Yangtse River estuary, the sea bed protection is researched. The sea bed protection is made of concrete block and fabric as a sunken mat covering the sea bed in front of the mound, which would protect the sea bed from current scour. The research is performed through three normal physical model tests whose scales are 1:25,1: 40 and 1:60, in order to eliminate the scale and model sediment effects. In the tests, two sections are studied in which the sea bed levels are-5.0m and-2.0m respectively, the current is steady, velocities are 3.0 m·s -1 and 2.0 m·s -1, the water level is+2.0m and the seabed of models is made of natural seabed sediment. The depth of eroded pit, the gradient of the pit edge and the length of the sunken mat remain protection near the sea bed of the mound are observed. When the seabed is eroded the section averaged current velocity reduces. The erosion characteristics near the sea bed of two sections is predicted by correlation analysis of erosion depth between measurement in tests and calculated ones, adopting Dou Guoren’s formula to calculate the sediment incipient motion velocity, assuming that it is critical erosion depth when the section averaged current velocity equals to the sediment incipient motion velocity. The correlation analysis method has a reference value to design and analogical research.
Year: 2004