高拱坝分层多股射流水垫塘冲击压强研究

Study of impinging pressure caused by multi-layer jets downstream of high arch dam

针对表孔采用宽尾墩深孔采用窄缝坎新型消能形式,利用物理模型试验研究表深孔联合泄洪形成的分层多股射流在不同流量比情况下对水垫塘底板的动水冲击压强特性的影响。建立了表深孔流量比对水垫塘底板的动水冲击压强变化的关系,实验证实了上游水股产生的水垫对下游水股冲击压强确实具有减小的作用,水垫塘内流态稳定,消能充分,深孔射流产生的最大冲击压强随着表深孔射流流量比的逐渐增大而减小。该研究可为实际工程中合理确定分层多股射流流量比提供参考依据,为峡谷区高坝工程的坝身泄洪消能布置及水垫塘的抗冲防护和结构稳定性分析提供有力科学依据。

A physical model of new energy dissipator of high arch dams was tested to study the impinging pressure on the floor of a plunge pool.The dissipator of flood releasing is a combination of flaring piers on the spillway outlet and flip bucket in the deep outlet.Correlation was obtained between the discharge ratio of the top outlet over the deep outlet and the impinging pressure.The test verifies that the water cushion formed by the upstream spillway jet reduces the hydrodynamic pressure induced by the deep outlet jet.The peak pressure decreases with the increase of discharge ratio.The results are helpful to dissipator design of high arch dams.