Research On Figure And Energy Dissipation Of The Large-scale Spillway And Diversion Tunnel

Flood discharge with energy dissipation is one of the prominent and key technical issues during high dam construction. Spillway and diversion tunnel is commonly used an discharge structures in hydroengineerin, transforming the diversion tunnel into a spillway and diversion tunnel is a common form in actual project. The two commonly main problems in flood discharging are cavitation erosion and downstream erosion. The current focus of the spillway and diversion tunnel research focused on aspects of cavitation erosion characteristics at anti-arch section, connecting section between longtaitou and longluowei. On the spillway and diversion tunnel, ski-jump energy dissipation at exit is often used due to advantages on the effect of energy dissipation, easy construction and low investment.In this paper, spillway and diversion tunnel on a single-hole and single-import structure being deep and pressure, has played a vital role during construction and operation period, due to the smaller working head of entrance during construction period, the larger discharging during operation period, the terrain of entrance and exit, and the larger fall head between entrance and exit, the probability growing negative pressure in tunnel will be enlarged, and the scour to downstream river bed and shoreside road will be more serious. The safety and reliability of hydropower station engineering during construction and operation period, the stabilization of downstream river bed and the third-period workshop will be directly affected by tunnel discharging capacity, the tunnel body and exit dissipation problems. At the same time, this project belongs to high-dam and high-flow-speed hydraulic tunnel, the problems of flow state inside tunnel, exit energy dissipation and larger fall head between entrance and exit are more prominent.Taking hydraulic model tests as the main methods and practical engineering as background, this paper studys the problems of tunnel body and exit energy dissipation of spillway and diversion tunnel on large-scale hydropower projects. After comparative research and test a variety of schemes, tunnel layout scheme with "longtaitou" type is presented ultimately. By adjusting the shape of the tunnel inlet and flip bucket to reach the optimal body with well cave flowing and positive pressure, and energy dissipation effect with high energy dissipation rate and small scour, it solves the negative issues and dissipation problems in spillway and diversion tunnel, meets the design requirements, achieves the desired objectives, and reduces the construction difficulty, reduces the impact of water splash on traffic bridge while optimizing energy dissipation effect.This paper perfectly solves the tunnel body and dissipation problems, having reference effect on similar projects, also having a certain academic reference and practical value.