The design of Three Gorges Hydropower Station
Changjiang Institute of Survey, Planning, Design and Research, Changjiang Water Resources Commission, Wuhan 430010, China
Using physical model and numerical simulation techniques, some technical problems were studied systematically, including layout of power station, measures of sediment and floating debris discharging, types of intake, embedded types of spiral case, layout of underground powerhouse tunnel group and block reinforcement. It was optimal in technique and economy with the arrangement of powerhouse at the dam-toe of both banks + underground powerhouse in the right bank, as well as the intake with a single and small orifice. The sediment and debris problems could be solved with disperse sediment ejection and floating debris discharging holes. With the adoption of techniques for spiral case such as heat and pressure preservation, cushion layer and combined embedding, the stable operation of generating units can be guaranteed. The arrangement of tailrace tunnel with sloping ceiling was better than that of tailrace surge tank. The technical requirements related to the embedding type of spiral case were proposed. The reinforcement of huge unfavorable blocks was discussed and the new idea for block reinforcement using anti-sliding piles and normal compressive stress of structural plane was put forward.