高拱坝坝身泄洪规模探析——以白鹤滩水电站为例

坝身泄洪规模对于高拱坝工程的泄洪安全有重大影响,是高拱坝水力设计中关键的技术参数之一。本文基于白鹤滩水电站坝身泄洪水工模型试验成果与水垫塘底板最大冲击压强宜小于15.0×9.8 kPa的技术基准,给出了该工程坝身泄洪规模的具体量值,并从水垫塘单位水体消能率角度与同类型工程进行了对比。试验研究表明,坝身泄洪规模与水垫塘底板冲击压强之间有显著相关性:在表孔单独泄洪运行工况下,随坝身泄流流量的增加,水垫塘底板最大冲击压强以幂函数的形式增大,且增幅十分明显;而在表深孔联合运行工况下,水垫塘底板最大冲击压强则主要取决于表孔与深孔泄流流量之比,基本上为线性关系。

Analysis of the maximum dam body flood discharge in large high arch dam: case study in Baihetan Hydropower Station

The scale of spillway has great influence on the safety of dam body for high arch dam during flood discharge, which is one of the key technical parameters in the hydraulic design of high arch dam project. According to the results of hydraulic model test for Baihetan hydropower station and the technical reference that the maximum impact pressure on water cushion pond floor should be less than 15.0×9.8 kPa, the maximum dam body flood discharge is given quantitatively, and compared to the others of the same kind project from the unit of water cushion pond water energy dissipation. The test results show that there is a significant correlation between the maximum dam body flood discharge and the maximum impact pressure on water cushion pond floor. In the case of surface outlet operation condition,with the increase of the dam body discharge flow, the maximum impact pressure on water cushion pond floor increases in the form of a power function,and increase obviously. In the case of surface and deep outlet joint operation condition,the maximum impact pressure on water cushion pond floor mainly depends on the discharge flow ratio of surface outlets to deep outlets, basically in a linear relationship.