关键词: 导流隧洞; 下闸封堵; 导流底孔; 乌东德水电站;

Abstract: The bottom diversion outlets are usually set for high arch dams at the bottom of the dam body to reduce the safety risk of gate closing, and at the same time to meet the needs of the later diversion and the downstream ecological water supply in initial water storage.However, due to the limited space at the bottom of the high arch dam body, setting the bottom diversion holes in the dam body can easily lead to complex structure stress of the dam body, occupation of the straight time of dam construction, large investment, small ecological flow during initial water storage period and even downstream dehydration and disconnection.Taking the Wudongde dam, the first high arch dam without bottom diversion outlet in China as an example, the risk analysis and countermeasures for gate closing under complex geological conditions were carried out.The specific analysis was carried out from the safety risks of gate facing super flood, gate instability, inadequate gate closing, underground cavern instability, abnormal leakage, gas explosion in the tunnel and time delay.And then the corresponding countermeasures were studied and formulated to ensure the safety of gate closing.Relevant safety risk response measures and management experience can provide reference for similar projects.

Key words: diversion tunnel; gate closing and plugging; bottom diversion outlet; Wudongde Hydropower Station;