On April 29, the concrete face slab of the main dam of the upper reservoir of the Zhejiang Tiantai Pumped Storage Power Station, constructed by Sinohydro Bureau 12 Co., Ltd., was fully completed. On the same day, the cutoff wall of the auxiliary dam of the upper reservoir was also completed, laying a solid foundation for the subsequent impoundment acceptance and the commissioning of the first unit.

The main dam of the upper reservoir of the Tiantai Pumped Storage Power Station adopts a concrete face rockfill dam, with a maximum dam height of 62.5 meters. The concrete face slab is divided into 44 panels, with a total pouring volume of 15,400 cubic meters. The main dam face slab uses low-heat concrete, with VF anti-cracking agent and basalt fiber added to the mix proportion. During construction, the slump of concrete entering the warehouse and the lifting speed of the slipform were strictly controlled, increasing the ultimate tensile value of the face slab concrete by 38.5% and reducing the adiabatic temperature rise by about 10°C. This effectively enhanced the anti-cracking performance of the face slab while ensuring the construction quality of the face slab concrete. The auxiliary dam of the upper reservoir adopts a concrete cutoff wall earth-rock dam, with a foundation treatment scheme of cutoff wall plus curtain grouting, and an embedded reinforced concrete structure design. The wall area is 8,902.2 square meters, with a maximum depth of about 36 meters.

The construction of the main dam face slab and the auxiliary dam cutoff wall faced difficulties in quality control, tight schedule pressure, and frequent adverse weather. The project team planned scientifically and organized meticulously. Under the premise of ensuring safety and quality, they optimized the construction scheme, accelerated the construction progress, and rationally allocated resources, successfully completing the pouring of the main dam face slab and the auxiliary dam cutoff wall.

The Tiantai Pumped Storage Power Station is a key implementation project of the national "14th Five-Year Plan" and a major construction project planned during the "14th Five-Year Plan" period in Zhejiang Province. It has a total installed capacity of 1.7 million kilowatts and is equipped with four reversible hydro-generator units with a single unit capacity of 425,000 kilowatts, the largest single unit capacity among domestic pumped storage power stations. The rated head of the power station is 724 meters, the highest in the world. After completion, the power station will be of great significance for promoting new energy consumption, improving the safety and stability of power grid operation, and promoting regional economic development.