Construction of Cofferdams for the Gezhouba Navigation Expansion Project of China's Three Gorges New Waterway Begins

en.Wedoany.com Reported - On October 10, the upstream and downstream cofferdams for the Gezhouba navigation expansion of China's Three Gorges New Waterway Project officially began construction in Yichang, Hubei, marking the project's full entry into the main construction phase. The two cofferdams being built will, together with the Gezhouba dam body and the left bank slope, form a water-retaining system for the construction area, creating conditions for dry foundation pit excavation and main structure construction of the new 10,000-tonne-class ship lock.

The Gezhouba navigation expansion project plans to demolish the existing No. 3 ship lock and build two lines of 10,000-tonne-class single-stage ship locks, each with effective chamber dimensions of 280 m × 40 m × 8 m. The new ship locks will share the upstream and downstream approach channels of the Sanjiang section with the existing No. 2 ship lock, and channel deepening, widening, and related supporting facilities will be carried out simultaneously.

The upstream cofferdam axis has a total length of approximately 835.94 m and consists of an earth-rock cofferdam and a rock dike cofferdam, connecting the Huangbai River estuary dike with the non-overflow dam section of Gezhouba. Construction work includes earth-rock filling, concrete cutoff walls, curtain grouting, and foundation pit dewatering, with plans to complete approximately 1,015,200 cubic meters of earth-rock filling and approximately 20,200 square meters of concrete cutoff walls.

The downstream cofferdam axis has a total length of approximately 960.85 m and adopts a combined structure of concrete cofferdam, steel pipe pile cofferdam, earth-rock cofferdam, and rock dike cofferdam. Among these, the steel pipe pile cofferdam is approximately 477.07 m long, and the concrete cofferdam is approximately 236.85 m long. The project also includes temporary sealing of the No. 2 ship lock discharge piers, seepage prevention for the left bank main foundation pit, and slope excavation of the downstream approach channel, with plans to use approximately 20,200 tonnes of steel pipe piles.

The upstream and downstream cofferdams are scheduled to be completed in early May 2027. During construction, deep-water dumping technology will be used upstream, while steel pipe pile cofferdam construction will be carried out downstream, with seepage prevention measures implemented simultaneously. After the cofferdams are completed, foundation pit dewatering, foundation excavation, and main concrete construction of the ship locks will proceed.

The Gezhouba navigation expansion project has a planned total investment of approximately 27.9 billion yuan and a total construction period of 83 months. During project implementation, the existing No. 1 and No. 2 ship locks will continue to handle navigation tasks, the new ship locks will be constructed in stages, and the upstream and downstream approach channels of the Sanjiang section will be renovated.