Research on Navigation Regulation of Liantuo Reach between the Three Gorges and the Gezhouba Project by Fixed-bed Physical Model

The Liantuo is one of the most typical navigation-obstructing shoals between the Three Gorges Project (TGP) and the Gezhouba Project. It is a deep-water rapid. When the discharge from TGP is larger than 25000m³/s, high velocity and turbulent flow are much more unsafely to navigating ships. So it is very necessary to improve navigation flow condition under larger discharge. The normal physical model with the scale of 1:100 is built and validated. And the two remote-control self-propelled ship models are used to test ship navigating safety. By the series of tests under large discharge, flow characteristics are analyzed and navigation-obstructing reasons are obtained. Then ideas for channel regulation are proposed, including expanding the upper part, lifting the lower part, and making overall plan. The schemes of single engineering are tested and analyzed, such as underwater reef-blasting or filling deep pool. And comprehensive improvement schemes are proposed, tested, and optimized. The results show that, navigation condition with the proposed scheme has been improved obviously. The limited discharge of safety navigation has been improved above 5000m³/s under different discharge. So the proposed regulation measures and comprehensive schemes are effective for the shoals with deep water and rapids.