导流洞采用“龙翘尾式”改建为泄洪洞技术的探讨

A probe on the technology for reconstructing diversion tunnel into spillway tunnel by "raising the diversion tunnel tail section"

介绍一种导流洞采用"龙翘尾式"改建为泄洪洞的技术,即在导流洞尾部设竖井段、水平转弯段和下游消能段。该技术要求导流洞按照运行工况一次建成有压圆形,这样洞内高速水流带来的气蚀问题基本不存在。经过竖井段后,上游水位与出口底板水头差降低,水力学、闸门受力等结构问题的处理难度均相应降低。下游消能工即使存在气蚀,由于在洞外检修条件好,问题也容易解决。

This paper presents the technology for reconstructing diversion tunnel into spillway tunnel by ＂raising the diversion tunnel tail section＂,i.e.,providing the vertical shaft section,horizontal bending section and downstream energy dissipation section at the tail of the diversion tunnel.The technology requires that the diversion tunnel should be built into a pressure one with circular section,so that the high-velocity flow in the tunnel would not cause cavitation.After the flow passes through the shaft section,the head difference between the upstream water level and the outlet bottom floor decreases,so that the difficulty in handling the structure problems such as gate stressing and hydraulics also decreases.Even if cavitation exists in the downstream energy dissipators,it is easy to solve due to good conditions for repair outside the tunnel.