On May 20, it was learned from the Project Department of Phase II of the Baima Navigation-Power Complex of Sinohydro Bureau 8 that the cofferdam of Phase II of the Wujiang Baima Navigation-Power Complex, the largest hydropower project under construction in Chongqing, achieved air-tight sealing in a single operation. This marks that the project has successfully withstood the test of deep water and high head, laying a solid foundation for subsequent safe flood control and main construction.

According to the introduction, cofferdam sealing is a key procedure in water conservancy, bridge and other construction projects. Through a temporary retaining structure to block water, the water at the location of the proposed building is drained, creating dry-land construction conditions for underwater operations such as foundation pit excavation and foundation pouring. The Phase II cofferdam of the Wujiang Baima Navigation-Power Complex is a year-round water-retaining earth-rock cofferdam, with a design water-retaining flow of 20,900 cubic meters per second. Among them, the upstream cofferdam has a total length of 296.5 meters, and the downstream cofferdam has a total length of 236 meters, with a maximum head of more than 50 meters upstream and downstream. Since the cofferdam closure at the end of last year, construction personnel have accelerated the concrete cutoff wall of the upstream and downstream cofferdams, curtain grouting under the wall, initial drainage of the Phase II foundation pit and other works, ultimately achieving cofferdam sealing ahead of schedule.

Huang Liang, chief engineer of the Project Department of Phase II of the Baima Navigation-Power Complex of Sinohydro Bureau 8, said that the victory of the cofferdam sealing milestone is a rigorous test of the construction results of the upstream and downstream cofferdam filling, cutoff wall and curtain grouting under the wall. It fully confirms the high quality and reliability of the earlier works and also lays a solid foundation for safe flood control of the project and subsequent main construction.

The Wujiang Baima Navigation-Power Complex project has an estimated total investment of 11.3 billion yuan, with an installed capacity of 480,000 kilowatts, mainly for navigation and also for power generation. After the project is completed, it can provide 1.762 billion kWh of clean energy annually, canalize 45.3 kilometers of waterway, and the ship lock will have an annual throughput capacity of 10.6 million tons. It will open up the "last mile" for southeastern Chongqing and northeastern Guizhou to enter the Yangtze River golden waterway, and is of great significance for promoting the comprehensive recovery of Wujiang navigation and promoting high-quality economic and social development of the river basin.

Deng Xiaohua, deputy manager of the project department, introduced that next, the project will fully enter the stage of large-scale foundation pit excavation. We will continue to carry forward the fine style of tackling difficulties, strictly control safety and quality, organize scientifically and advance efficiently, and go all out to sprint toward the annual sequence transition milestone goal, contributing greater strength to building a "safe century-quality project".