彭水水利枢纽泄洪消能设计研究

Design of flood releasing and energy dissipation for Pengshui Project

乌江彭水水利枢纽坝址地处高窄峡谷河段，因该枢纽具有洪峰流量大、下游水位变幅大、泄洪与通航矛盾突出等特点，故其泄洪消能设计就成为枢纽建筑物布置及水工设计的关键因素。通过方案比选，在泄洪建筑物布置上采取的优选方案为大坝中部设７个表孔、两岸边设２条滑雪道，当洪水频率Ｐ≤５％时，开启２个近岸底孔联合泄洪。在泄洪建筑物体型设计上，除优化表孔及底孔设计参数、合理确定结构型态外，对左、右滑雪道分别采用异型扭鼻坎和连续式鼻坎型式；消能防冲设计则根据不同设计洪水条件采取挑流或挑流与面流相结合的消能方式，并且对滑雪道、岸坡和坝下冲坑进行了防护处理设计。

The damsite of Pengshui Project is located in a deep and narrow gorge reach. Since the Project is characterized by large peak discharge of flood, great variation in downstream water level, remarkable contradiction between flood release and navigation, etc., the design of flood release and energy dissipation becomes a key element of the layout and hydraulic design of the structures. Through comparison of various alternatives, the optimal alternative in terms of layout of flood releasing structures is recommended, which has 7 surface sluices in the central portion of the dam, 2 ski jump spillways on both banks and 2 bottom outlets near both banks. When flood frequency P≤5% ,the 2 bottom outlets will be used in combination with the surface sluices and ski jump spillways to release flood. In design of the flood releasing structures,in addition to optimization of the design parameters and reasonable determination of the structural figuration of the surface sluices and bottom outlets, an abnormal distored deflecting bucket and a continuous deflecting bucket are provided for the right and left ski jump spillway respectively. Trajectory flow or trajectory flow together with surface flow is used in accordance with different design flood for energy dissipation and scour prevention. Some protective measures are taken for the ski jump spillways, bank slope, and scour pit in design.