Author(s): C. Liu; Y. He; Z. Y. Wang
Linked Author(s):
Keywords: Outfall; Diffuser; Sedimentation; Flush
Abstract: An invariable cross-section diffuser is proposed in the Jiaxing outfall of Jiaxing Sewage Project for the geological and constructional reasons. Severe sediment deposition may be caused in the offshore end if no measures are taken. In this paper, the authors present a sediment-laden model studies on the sedimentation in the invariable cross-section diffuser. The results show that the sediment bed with the height increased from the shore to the offshore end in the diffuser will be formed in the equilibrium state of sediment deposition and scouring in certain discharge. For the specific project of Jiaxing outfall, the sediment bed will influence the risers' discharge when the total discharge flow is below 3.5 m3/s; whereas, it will not influence the risers' discharge significantly when the total discharge flow is larger than 5.2 m3/s. Measures to reduce the sediment deposition in the diffuser are put forward. It is suggested that the curved ends in diffuser have certain effect on reducing the sediment bed height there; flushing regularly contributes to preventing severe sediment deposition; and the ports numbers of risers increasing along the diffuser can low the sediment bed obviously so as to improve the effluent condition of the risers at the ends.
Year: 2003