The power station hub consists of barrage, drainage building, water conveyance system, underground powerhouse and ground switch station. The barrage is a roller compacted concrete gravity dam with a maximum dam height of 72.40m, a dam crest elevation of 634.40m, a dam crest length of 206m and a dam crest width of 7.50m m. The upstream face of the dam is vertical, and the downstream face of the dam section has a dam slope of 1:0.72. The overflow dam section is located in the middle of the dam, and the elevation of the dam crest is 621m. There are three overflow surface holes and three 12m× 12m radial gates. Practical weir connection 1:0.7 dam slope, 20m arc radius and 28 projection angle. The diversion system is arranged on the right bank, and consists of water intake, diversion tunnel, upstream surge shaft, high-pressure shaft and pipeline, reinforced concrete bifurcated pipe, etc. The water inlet of the power station is a bank tower structure, which consists of trash rack, horn section, lock chamber and gradual change section. The elevation of the entrance floor is 598m, and the elevation of the maintenance platform is 635m. The water inlet is provided with three trash racks and an emergency door with an orifice size of 5×6m. The diameter of diversion tunnel is 6.80m, and the bottom slope i=3.42‰. Most of the tunnels are unlined, and some of them are lined with reinforced concrete and supported by bolting and shotcreting. The high-pressure pipeline consists of upstream surge shaft, high-pressure well, high-pressure horizontal section, bifurcated pipe and steel branch pipe section. High-pressure shaft and surge tank are arranged in the open air, with surge tank height of 8m, shaft height of 7 1.05m, excavation diameter of 8.90m and lining inner diameter of 567.77m; high-pressure shaft height of 38 1.60m, lining inner diameter of 4.7m, total shaft height of 452.65m, surge tank with 5×5m emergency gate and maximum surge level of 640. Y-shaped symmetrical bifurcation is adopted. C30 reinforced concrete lining is adopted for the shaft, lower section and bifurcated pipe. The maximum static head of the bifurcated pipe is 450m, the diameter of the main pipe lining is 4.70m, the diameter of the branch pipe lining is 2.70 m m, and the reinforced concrete branch pipe is behind the bifurcated pipe, with a length of 16m. The steel branch pipe is 89.3m long and made of 16Mn steel, with a wall thickness of 48-50mm.

Construction technology of high-pressure diversion shaft

The total height of the diversion shaft of Zhouning Hydropower Station is 453m, which is difficult to construct and requires high technology. Therefore, the construction technology of high-pressure diversion shaft project of Zhouning Hydropower Station is studied, and the feasibility of the technology, safety technology and quality achievements adopted in shaft construction is verified. The results show that the safety system of personnel, materials and concrete transportation, anti-falling safety technology, trackless anti-rotation control technology and construction transportation coordination technology have solved the technical difficulties of long shaft construction, greatly improved the safety guarantee, and have the advantages of low cost, simple technology and strong popularization. The application of sliding mode technology, reverse drilling rig and bolting and shotcreting support technology has comprehensively and effectively controlled the major hazards in vertical shaft construction and realized zero accidents in vertical shaft construction.