关键词: 航道工程, 河道演变, 细沙输移, 分汊河段, 数值模拟, 起动流速

Abstract: The fine sediment deposition in the permanent backwater zone of the Three Gorges Reservoir has exceeded its predictions made during its design period. A series of laboratory experiments were done on samples of fine sediment from the typical part of Huanghuacheng in the Three Gorges Reservoir. Compared with the 4 existing formulas, an improved incipient velocity function for fine sediment deposit was developed including its influence of water pressure and molecular force, and a 2D hydrodynamic-morphological model for simulating channel evolution processes was improved according to the movement of the physical movement of local fine sand. The proposed velocity formula was considered in calculating fine sediment transport, and the improved 2D numerical model applied in Huanghuacheng. Comparisons between model simulation results and field measurements were in agreement. The result shows that the 2D model can predict fine sediment behavior and assist navigation management decisions in the permanent backwater region mentioned above.

Key words: waterway engineering, fluvial process, fine sediment behavior, braided river, numerical simulation, incipient velocity