Optimization of the earthwork excavation-filling balance and allocation for the upper reservoir of a pumped storage power station

It is very important to achieve an excavation-filling balance and conduct reasonable earthwork allocation in the construction of pumped storage power stations to improve their technological and economic benefits. In this work, adopting the upper reservoir of a pumped storage power station in Guizhou, China, as an example, the excavation and filling volumes of the upper reservoir were calculated by simulating the excavation process of the reservoir basin and embankment filling construction of concrete panel rockfill dams to reach an excavation-filling balance. Moreover, rockfill dam filling was optimized in stages. On this basis, an optimization model aiming to obtain the minimum earthwork allocation cost was built, and a genetic algorithm was used to solve the optimization model. The results showed that the excavation and filling volumes of the upper reservoir are 3.8966 million m3 and 4.0949 million m3, respectively, and the downstream slope of the rockfill dams is 1:2.12, achieving excavation-filling balance. The total storage capacity of the upper reservoir is 8.3691 million m3, which meets the designed storage requirements. In addition, the rockfill dams of the upper reservoir should ideally be filled in three stages. The minimum disequilibrium coefficient of Dam #1 is 1.00, with a corresponding filling time of 10.01 months, while the minimum disequilibrium coefficient of Dam #2 is 1.01, with a corresponding filling time of 21.32 months. The minimum cost of earthwork allocation of the upper reservoir is CNY 4.8752 million yuan.