Method for reconstructing temporary diversion tunnel into permanent flood discharge facility

Abstract

The invention provides a method for reconstructing a temporary diversion tunnel into a permanent flood discharge facility. The method comprises the steps that firstly, an entrance of the original diversion tunnel (1) is blocked; secondly, an entrance curve section of the diversion tunnel and a straight section behind the entrance curve section are reconstructed into an energy dissipation pressure forebay (2), and the wall surface of the tail end of the energy dissipation pressure forebay is provided with a jet flow outlet (3), so that the diversion tunnel section behind the outlet becomes a free flow section (6) of a permanent flood discharge tunnel, wherein the straight section is at least five times longer than the entrance curve section; thirdly, at least one flood discharge tunnel (4) is newly constructed at the position above the entrance of the blocked diversion tunnel, wherein the bottom surfaces of entrances of the newly constructed flood discharge tunnels are at least 2m higher than the highest position which silt silting at the entrances can reach; and fourthly, each newly constructed flood discharge tunnel (4) is connected with the energy dissipation pressure forebay (2) through at least one connecting pipeline (5), and the axes of the newly constructed flood discharge tunnels (4) intersect with the axis of the energy dissipation pressure forebay (2). By means of the method, not only can the diversion tunnel with the planar curve section be smoothly reconstructed and utilized, and investment is saved for a whole water conservancy and water power project, but also the energy dissipation effect can be improved, and the service life of a building is prolonged.

Description

technical field [0001] The invention belongs to the technical field of reconstruction of water conservancy and hydropower facilities, and in particular relates to a method for rebuilding a temporary diversion tunnel in a water conservancy and hydropower project into a permanent flood discharge facility. Background technique [0002] During the construction of water conservancy and hydropower projects, it is often necessary to temporarily block the river to facilitate construction in the original river course. At this time, some temporary buildings need to be built to divert the water in the river to the downstream of the construction area. Diversion tunnels are often built Such a temporary structure. In order to save engineering investment, the shorter the length of the diversion tunnel, the better, which leads to the existence of plane turning sections in the diversion tunnel. For such temporary drainage structures, they are generally abandoned after the construction of th...

Images