Method for safely plugging diversion tunnel under bad geological condition of high water head of hydropower engineering

Abstract

The invention discloses a method for safely plugging a diversion tunnel under a bad geological condition of a high water head of hydropower engineering. The method includes the steps of gate switching-on, water pumping and plugging, wherein plugging includes safety protection plug construction, bad geological section surround rock reinforcing construction and permanent plug construction. Accordingto the method, aiming at the characteristics of diversion tunnel plugging under the bad geological condition of the high water head of hydropower engineering, a safety protection plug is adopted, badgeological section surround rock is reinforced, through two guarantees, the risk of losing stability of the bad geological section surround rock under the action of the high water head is effectivelyavoided, the safety guarantee rate of gate switching-on and plugging of the diversion tunnel is increased greatly, meanwhile sudden water burst in the tunnel can also be blocked by the safety protection plug when an inlet gate of the diversion tunnel is damaged, and thus the safety of plugging construction workers is guaranteed; and implementation operability is high, a safety protection plug concrete pouring and bad geological section consolidation grouting process is simple, the plugging effect is good, the construction period is short, the construction cost is low, and the method has greatapplication and popularization 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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