高拱坝表孔宽尾墩水力特性试验研究

Experimental study on hydraulic characteristics of flaring gate piers of surface spillway in the high arch dam

采用模型试验方法,对宽尾墩消能工应用于高拱坝表孔后,其下泄水流流态、泄流能力、水垫塘流态及水垫塘底板冲击动压等水流特性进行了研究。结果表明:高拱坝表孔宽尾墩流道内存在自由跌流、急流冲击波及缓流三种流态;当处于急流冲击波流态时,其下泄水舌呈窄而高且长的窄长流态,水舌纵向扩散效果明显,并且宽尾墩体型几何参数变化不会影响其泄流能力;水垫塘底板最大时均冲击动压值随着堰顶水头的增高而增大,随着宽尾墩收缩比的增加而增大,随着墩尾折角的增大而减小,随着坝面倾角的增大而减小。

In this paper,the hydraulic characteristics of flaring gate piers applied to the surface spillway in a high arch dam were studied on a physical model,such as plunging stream flow pattern,discharge capability,flow pattern and time averaged impact pressure on the plunge pool bottom etc.The results showed that there were three flow patterns as free drop,shock wave and slow flow in the channel of flaring gate piers on the surface spillway.When the flow pattern of flaring gate piers channel was shock wave,the narrow and long jet could be gotten,and the change of flaring piers parameters did not have any effect on the discharge capability of surface spillway.And the bigger the water head of weir is,the bigger the maximum time averaged impact pressure on the pool bottom is.The bigger the contracting scale of flaring piers is,the bigger the maximum time averaged impact pressure is.As while,the bigger the deflection angle of pier＇s tail and plunging angle of the channel bottom of spillway are,the smaller the maximum time averaged impact pressure is.