窄缝挑坎在高拱坝深孔中的初步应用研究

在锦屏一级水电站（拱坝坝高305 m）整体水工模型上将窄缝挑坎应用于高拱坝泄洪深孔，对窄缝挑坎体型参数选择和布置进行了试验研究。试验结果表明，窄缝挑坎应用于高拱坝深孔，可以获得窄长下泄水流流态；边墙压力测量结果显示，深孔采用窄缝挑坎后边墙无负压出现，但在窄缝收缩起点附近存在压力增大；射流水舌在水垫塘内纵向扩散效果显著，水垫塘底板时均冲击动压分布相对常规挑坎时而言更加坦化，底板冲击动压差也大大减小，这对水垫塘底板稳定和减小射流冲刷有利.

Preliminary application of slit-type flip bucket to bottom outlet of high arch dam

On the holistic hydraulic model of Jinping I Hydropower Station（with a 305 m high arch dam），the slit type flip bucket is applied to the bottom outlet of the high arch dam，so as to make an experimental study on the layout and the selection of the configuration parameters of the slit type flip bucketThe experiment result shows that a long narrow pattern of discharge flow can be got，if the slit type flip bucket is applied to the bottom outlet of high arch dam; for which the measurement of the pressure on the side wall reveals that no any negative pressures occur on the side wall after the application of the slit type flip bucket to the bottom outlet，however，the pressure is increased near the contraction starting point of the slit along with an obvious effect of longitudinal diffusion of the jet flow within the plunge poolMoreover，the distribution of the time average?impulse dynamic water pressure on the bottom of the pool is more smooth with a largely decreased pressure difference，when compared with the conventional flip bucketThis is quite favorable for stabilizing the bottom of plunge pool and decreasing the jet flow scouring as well