The prefabricated fishway with the highest altitude and the largest drop under construction in the world is fully connected

Recently, as the last prefabricated beam was hoisted into place, it marked that the prefabricated fishway with the highest altitude and the largest drop in the world, which was built by China Huadian and the 9th Bureau of China Power Construction and Hydropower Engineering, has been completed.

The fish pass is a fish-passing structure for fish migration, an important channel for upstream and downstream fish migration, and plays an important role in protecting the ecological environment of the water basin and realizing the ecological security of the water area.

The fishway of Tibet DG Hydropower Station is arranged on the right bank of the dam site, mainly composed of the entrance of the fishway, the exit of the fishway, and the pool room of the fishway. It is the first time in the country that a large number of vertical seam fishways have been used in prefabricated assembly technology (the whole fishway guide baffle and the folded section pool chamber are all prefabricated).

Due to the narrow terrain of the valley of the power station, almost all the fishways with a drop of up to 80 meters between the upstream and downstream are arranged on the steep terrain, and the bottoms of the fishways with complex engineering layout are large concrete steel tube columns. Under the high-strength construction conditions, the prefabricated beam hoisting, the column base strip concrete pouring, and the steel pipe column installation all interfere with each other. At the same time, there are also problems such as the small available range of large-scale equipment layout, the cross operation with the high slope of the main section of the power station, and the hoisting construction in winter.

In order to ensure the quality of project construction, the No. 9 Hydropower Bureau carefully organized the construction, actively explored the method of constructing ecological fishway, and overcome various technical problems along the way. During the period, the adjustable telescopic formwork for prefabricated beams, the vertical alignment device for large-scale steel pipe columns, and the new connection and fixing methods for prefabricated guides/clapboards, etc., were successfully used. In addition, new technologies such as the installation and reinforcement technology of the formwork for the thin-walled partition wall of the deep groove of the fishway, the key technology of concrete pouring and heat preservation in the low temperature season, and the key technology of the safe construction of the long fishway of the high dam have effectively accelerated the construction progress of the fishway during the construction process.

In the field of fishway construction, a number of national invention patents and utility model patents have been applied for, and 5 patents have been authorized. Obtained 1 company-level construction method, 1 QC I category achievement of the Hydraulic Engineering Association, and published 5 papers.

Up to now, the main project of the fishway has been completed, and the trial operation of the fishway is planned to be realized by the end of May.