中文摘要：

针对过水围堰消能防冲特征,提出在消能平台上设置水垫池的方法。通过专门的水力试验装置对消能平台水垫池进行研究,并与无水垫池时的水力特性对比分析。研究表明：水垫池的设置相当于增加了水垫深度,特别在下游基坑水位相对较低、消能平台水深较浅时,可明显改善消能效果;消能平台出口流速较无水垫池时明显降低,能减轻水流对下游护面及堰脚的冲刷;与无水垫池时底板压力峰值出现在消能平台进口附近不同,设有水垫池时压力峰值出现在尾坎附近,可有效缓解消能平台进口的冲击力。采用合适的消能平台水垫池结构,可提高消能防冲作用、改善底板受力条件,有利于过水围堰安全溢洪。

英文摘要：

Owing to the characteristics of energy dissipation and scour prevention for overtopped cofferdam, the water-cushion pool on the en- ergy dissipation platform was put forward. The water-cushion pool of energy dissipation platform was investigated by a special hydraulic test device, and its quality was compared with the hydraulic characteristics without water-cushion pool. It shows that setting water-cushion pool is equivalent to an increase in water cushion depth, which can significantly improve energy dissipation, especially in the conditions of the down- stream foundation pit water level relatively lower or the shallow water-depth on energy dissipation platform. The outlet flow velocity of energy dissipation platform obviously decreases compared with no water-cushion pool, which can reduce the overflow scour on downstream protective facing and cofferdam foot. The floor pressure peak occurs near the inlet of energy dissipation platform without water-cushion pool, while the floor pressure peak appears near the end sill with a water-cushion pool, which can effectively alleviate the impact on the inlet of energy dissipation platform. It can be concluded that the energy dissipation and scour prevention as well as the floor force condition of energy dissipation platform will be improved by setting an appropriate water-cushion pool structure for the energy dissipation platform, which favors the overflow safety of overtopped cofferdam.