A method for safely sealing diversion tunnels under high water head and unfavorable geological conditions in hydropower projects

Abstract

The invention discloses a method for safely sealing diversion tunnels under high water head and adverse geological conditions in hydropower projects, which includes lowering gates, pumping water and sealing, wherein the sealing includes construction of safety protection plugs, reinforcement construction of surrounding rocks in adverse geological sections and permanent construction. Plug construction. The method of the present invention aims at the plugging characteristics of the diversion tunnel under the adverse geological conditions of high water head in hydropower projects, adopts safety protection plugs and reinforces the surrounding rock of the unfavorable geological section, and effectively avoids failure of the surrounding rock under the high water head of the unfavorable geological section through two guarantees. It can greatly improve the safety assurance rate of the closure of the diversion tunnel lower gate, and at the same time, the safety protection plug can also block the sudden water gushing in the tunnel when the diversion tunnel entrance gate is damaged, so as to protect the safety of the construction workers. The invention has strong operability, simple technology for pouring concrete for safety protection plugs and consolidation grouting for unfavorable geological sections, good plugging effect, short construction period and low construction cost, and has good popularization and application value.

Description

technical field [0001] The invention belongs to the technical field of hydraulic structure engineering construction, and in particular relates to a method for safely sealing diversion tunnels under high water head and adverse geological conditions in hydropower projects. Background technique [0002] The diversion tunnel is used to divert and divert the river water flow under construction after the cofferdam is built upstream and downstream of the hydropower project to ensure that the dam project is constructed on dry land. After the buildings and flood discharge structures are completed, they will lose their function and need to be blocked. The closure of the diversion tunnel marks the beginning of water storage in the hydropower project, which is the key control condition for reservoir water storage and an important milestone event in the construction of hydropower projects. Whether the plugging of diversion tunnels can be completed smoothly and in time plays an extremely ...

AI Technical Summary

Problems solved by technology

[0002] The diversion tunnel is used to divert and divert the river water flow under construction after the cofferdam is built upstream and downstream of the hydropower project to ensure that the dam project is constructed on dry land. After the buildings and flood discharge structures are completed, they will lose their function and need to be blocked. The closure of the diversion tunnel marks the beginning of water storage in the hydropower project, which is the key control condition for reservoir water storage and an important milestone event in the construction of hydropower projects. Whether the plugging of diversion tunnels can be completed smoothly and in time plays an extremely important role in realizing the benefits of the entire project on schedule. Practice has proved that there have been many failures of diversion tunnel plugging in hydropower projects at home and abroad, causing major economic losses and causing major public accidents. Safety hazards and major public opinion, therefore, the diversion tunnel blockage must be absolutely foolproof

[0003] The position of the diversion tunnel plugging head must be set at the position of the anti-seepage curtain of the hydropower project, and it is combined with the curtain to form a part of the anti-seepage system, so that the entire anti-seepage system of the water-retaining building becomes a whole. Otherwise, regardless of the plugging head Whether in front of the anti-seepage curtain or behind the anti-seepage curtain, the diversion tunnel and its surrounding rock may become seepage channels. After the blockage, the water level of the reservoir rises rapidly, and the surrounding rock of the diversion tunnel at this distance will bear the effect of high water head. Since the diversion tunnel is a temporary structure, the geological conditions are often worse than those of the main permanent project. There will be a risk of instability under high water head, which will determine the success or failure of the plugging of the diversion tunnel. In addition, if the upstream inlet gate is damaged during the permanent plugging construction, the sudden water gushing in the tunnel will also pose a huge safety risk to the plugging construction personnel. Therefore, it is necessary to study a safe sealing method for diversion tunnels under high water head and unfavorable geological conditions in hydropower projects.

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