导流洞复合式出口消能体型的研究与应用

Research and Application of Composite Outlet Energy Dissipation Type in Diversion Tunnel

狭窄河谷中高水头、大流量、复杂地质条件的工程前期导流工程面临高速水流泄洪问题,对消能体型要求较高。基于水工物理模型试验对某水利枢纽导流洞出口消能体型进行优化探索,先后提出右岸导向、洞线偏移、左岸分流、强迫消能+左岸分流4种布置方案,通过对水流流态、流速和冲刷特性等水力参数进行测定和比选,最终推荐强迫消能+左岸分流的复合式消能体型,并对推荐体型对大小流量工况的适应性进行导流全过程试验分析。结果表明:复合式消能体型在各工况下消能效率较高,围堰及左岸近岸流速明显降低,分散水流能有效封堵回流,水面波动强度减弱,主流顺利归槽,冲淤情况良好,保护左岸免受冲刷。该复合式消能体型能够满足工程消能及安全稳定要求,可为具有类似特点的导流洞工程的出口设计提供参考。

The pre-engineering diversion project in narrow river valley with high water head,high discharge and complex geological condi-tions faces the issue of high speed water discharge,which requires higher energy dissipation body type.Based on hydraulic physics model test,the energy dissipation type at the outlet of diversion tunnel of a hydraulic project was optimized and explored,and four layout schemes including right bank orientation,tunnel line deviation,left bank diversion and forced energy dissipation+left bank diversion were proposed.Through the determination and comparison of hydraulic parameters such as water flow pattern,velocity and erosion characteristics,the com-pound energy dissipation type of forced energy dissipation+left bank diversion was finally recommended,and the adaptability of the recom-mended type to the large and small flow conditions was tested and analyzed throughout the diversion process.The test results show that the composite energy dissipation body type has higher energy dissipation efficiency under each working condition,the flow velocity of cofferdam and left bank near shore is obviously reduced,the dispersed water flow can effectively block backflow,the intensity of water surface fluctua-tion is weakened,the main flow returns to the channel smoothly,the scouring and siltation situation is good and the left bank is protected from scouring.The composite energy dissipation body type can meet the project energy dissipation,safety and stability requirements,and can provide reference for the outlet design of the diversion tunnel project with similar characteristics.