Author(s): Chunju Zhao; Yihong Zhou; Hongmin Guo
Keywords: Flood control; Overtopped cofferdam; Construction period; Jingpin II hydropower station
Abstract: During construction of Jinping II hydropower junction, the river flow should be retained by cofferdam and be diverted via a single tunnel in dry seasons, while in flood seasons, it would overtop the cofferdams and pass through the foundation pit. With physical model tests, the velocity distribution at critical positions over the overtopped earth-rock cofferdams is test under the design flux and other working conditions, as well as hydraulic parameters such as press distribution over cofferdam slopes. Moreover, the flow regime over cofferdams is observed, and then the section forms of cofferdams are optimized to ensure the safely passing of flood during construction.