用能量法计算隧洞出口挑流下游基岩冲刷

Application of Energy Approach to Estimating Scour Depth

高土石坝的由导流洞改建而来的永久性泄洪洞,由于导流洞的高程低,泄洪落差大、流速高,下游的基岩冲刷问题引起人们的重视。能量法是计算基岩冲刷深度的较新方法,根据参证坝址(原型已建工程)和待建坝址的平均水股剩余能量与冲刷深度的关系用冲刷能量指标ESI来估算大坝下游岩基冲深。将能量法应用于紫坪铺1#泄洪排沙隧洞挑流基岩冲刷中,并将计算结果与经验公式和试验数据比较,证明此法可行,且效果较好。

Many permanent spillway tunnels of high earthrock dams are rebuilt from their diversion tunnels. Scour problem is focused upon because of their high water heads and velocities. Energy Approach is a new method to estimate scour by using ESI (Estimating Scour Index), which represents the relationship of scour depth and mean remain energy between the dams built and to be built. The method is used in this article to estimate the depth of scour downstream of 1# spillway tunnel of Zipingpu Project, and is illustrated working fine by comparing its results with data from model test and empirical formula. 