向家坝工程坝面隔墙水动力特性及体型优选研究

Study on the Hydrodynamic Characteristics and Shape Optimization of the Dividing-Wall of Xiangjiaba Project

向家坝水电站混凝土重力坝采用底流消能形式,溢流坝坝面的表孔和中孔采用高低坎间隔布置,各孔之间的水流以隔墙分开。当大坝大流量泄洪时,部分隔墙淹没在消力池中水跃的跃首位置,在低频大幅水流波动的作用下,其动力响应和稳定性问题十分突出。通过模型试验研究了隔墙在泄洪时的水动力特性,并将模型试验结果应用于有限元数值计算,分析了隔墙的模态和动力响应,进而评价其安全稳定性,得出的结论是:隔墙在泄洪时不会发生与水流的随机共振,但是,靠近挑坎的隔墙根部动应力较大,因此,在隔墙的结构设计时应采取适当措施(如:配筋)予以加强。同时,为了改善隔墙的受力条件,通过体型方案优选得到受力条件较好的隔墙体型。该成果有实际的应用意义,可为今后类似的工程提供参考。

Bottom-flow dissipation was applied to the concrete gravity dam of Xiangiiaba Project. The surface holes and central holes on the overflow dam were arranged in the form of high and low sills, and the water-flow of holes were divided by the dividing-wall. When the dam discharged flood,because some parts of the dividing-wall were submerged in the first position of hydraulic jump in the plunge pool and the dividing-wall was affected by the water-flow of low frequency and large range, the problem of its dynamic responses and stability was prominent. In this paper, the hydrodynamic characteristics of the dividing-wall were studied by model experiments, and the experimental results were applied in the finite element method to analyze the modality and the dynamic responses of the dividing-wall,and the safety and the stability of the dividing-wall were evaluated based on the results. The conclusion was that the dividing-wall would not occur stochastic resonance in water when the dam discharged flood, but the stress was great in the root of the dividing-wall near the bucket, Therefore, some appropriate measures, such as re- inforcement should be taken to strengthen the dividing-wall when it was designed. The achievement of this paper had practical significance, and it would provide a reference for future similar projects.