Feicui reservoir

Feicui reservoir

This entry is compiled and applied by "popular science China" Science Encyclopedia

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Feicui reservoir is located on Beishi stream, a tributary of Xindian stream. It covers all the forest area of Xinbei Shiping, and part of Shuangxi District, Shiding district and Xindian district. It is about 30 kilometers away from Taipei city. The total catchment area is 303 square kilometers and the reservoir capacity is 406 million cubic meters. The main function is water supply, with power generation, flood control and other functions. It is a multi-objective dam.

evolution

The main purpose of the development of feicui reservoir is to serve as a long-term water source for the Taipei area. It is a water source project in the fourth phase of the construction plan for tap water in the Taipei District. The plan was started in 1971, and the preliminary research report was completed in 1972, the feasibility report was completed in 1974, and the final research report was completed in 1978. The Taipei municipal government set up the Taipei feicui Reservoir Construction Committee to be responsible for the construction Design supervision of Xingcheng Engineering Consulting Co., Ltd. and construction of Rongmin Engineering Co., Ltd. started in August 1979 and completed in June 1987. After the completion of the project, the Taipei municipal government will set up the feicui Reservoir Management Bureau to be responsible for the operation and maintenance.

In order to manage and maintain the upstream catchment area of qingtanyan in xindianxi (including beishixi and nanshixi), the Taiwan provincial government set up the Taipei water resources specific area management committee (hereinafter referred to as the water resources committee) in 1984, which was reformed into the Taipei water resources specific area management committee of the "Ministry of economic affairs" of the Taiwan authorities in 1999, and the Taipei water resources specific area Management Bureau of the "Ministry of economic affairs" of the Taiwan authorities in 2002.

Basic information

Catchment area: 303 square kilometers

Maximum normal water level: 170m

Maximum possible water supply level (CMS): 171m

Full water area: 1024 ha

Total water storage: 406 million cubic meters

Planned effective storage capacity: 327 million cubic meters

Existing effective storage capacity: 340117000m3

Planned annual water consumption: 126.144 million cubic meters

Water right: 86.77 m3 / S

Dam type: bidirectional bending variable thickness concrete arch dam

Crest elevation: 172.5m

Maximum dam height: 122.5m

Crest length: 510m

Crest width: 7M

Dam volume: 703675 M3

Auxiliary dam (concrete arch dam): 242m x25m

Spillway type: horizontal skip type

Design spillway discharge: 7670 m3 / S

Spillway control water gate type: 8 radial gates, each 14m wide and 9.3m high

Outlet type: River outlet (diameter 1.6m)

Effluent design flow: 47 m3 / S

Outlet control water gate type: ring sliding gate and Hepburn valve

Type of sand discharge channel: three scouring channels, 2.5m wide, 3.0m high and 26m long

Type of control water gate of sand discharge channel: 3 fixed wheel control gates, each 2.5m wide and 3M high, and water retaining gate

Scour channel: fixed wheel gate

Flood discharge tunnel span: 297m (diameter: 10m)

Design discharge of flood discharge facilities: 9870 m3 / S

The maximum possible flood volume is 10500 m3 / s.

Project cost: 11.45 billion yuan

Other ancillary facilities: Block B of 70000kw semi underground reinforced concrete power plant, one generator set

Maximum power consumption: 102.11 m3 / S

Tap water: meet the tap water demand in 2030

Power generation: 222700000 kwh per year

Feicui arch dam

Feicui arch dam is located in the downstream of beishixi, a tributary of Xindian River in Taiwan Province, China. It is the barrage of feicui reservoir, 30km away from Taipei city. It is a water source project for 4.5 million people in Taipei area.

hydrography

The drainage area above the dam site is 303 square kilometers. The total storage capacity of the reservoir is 406 million cubic meters, and the effective storage capacity is 327 million cubic meters. The project consists of a dam and a power station (Fig. 1 and Fig. 2). The dam is a double curvature variable thickness three core concrete thin arch dam with a height of 122.5m, a total crest length of 510m, a crest thickness of 7m and a bottom thickness of 25m. The design discharge of the flood discharge facilities is 9870 m3 / s, the type of the spillway on the dam crest, the installation of 8-hole radial gate, and the size of 14m × 9.3m. There are 3 holes in the flushing channel, and the fixed wheel gate is installed, with the size of 2.5m × 3M. The spillway tunnel is 10m in diameter and 386.13m in length. There are also two dams and stilling ponds. The installed capacity of Bahou hydropower station is 70mW (1 unit), with an average annual power generation of 223 million KW · h for many years.

Dam characteristics

Since the dam is only about 30km away from the downstream Taipei area, the dam safety is very important

(1) A new construction method for the treatment of mud joint in foundation layer. The foundation of the dam is composed of hard and dense sandstone and siltstone interbedding. The strike of the rock strata is parallel to the river course, and the dip angle is about 40 degrees. The left bank is a forward slope, and the right bank is a reverse slope. There are mud containing joints with different thickness between rock planes and other three groups of joints, which constitute the main weak plane of the dam site. After evaluation, it is considered that the common foundation treatment method is difficult to meet the design requirements, so it is decided to adopt the treatment method of filling with non shrinkage cement mortar after washing all the large and small mud joints in the dam foundation stress area with ultra-high pressure water column in the dam foundation pit. The treated dam foundation is combined into a whole. After the treatment, the core is drilled for shear test, which proves that the shear strength is greatly improved and higher than the design requirements.

(2) High standard seismic design is adopted. According to the standard of American nuclear power plant, the seismic check of the dam body is carried out by using three kinds of earthquakes, namely, maximum probable earthquake (MCE), design basis earthquake (DBE) and operational basis earthquake (OBE). The determination of the scale and source location of the three earthquakes is based on the statistical analysis of historical seismic data and the investigation of fault activity. Then, the peak ground acceleration of the dam site corresponding to the three kinds of earthquakes is 0.4g (MCE), 0.25g (DBE) and 0.2g (OBE) by using the appropriate attenuation formula, and the special design response spectrum and artificial acceleration time history line of the dam site are formulated. In seismic check, horizontal earthquake and vertical earthquake are considered at the same time. Besides pseudo static method of seismic coefficient, response spectrum method and time duration method are used for analysis.

(3) Conservative design flood is adopted. The design flood of reservoir flood discharge facilities generally depends on the dam type. Because the earth rock dam does not allow flood to overflow the dam crest, the design flow of spillway adopts the maximum possible flood. Because the overtopping of concrete dams will not cause safety concerns, most of them are designed with the flood with a return period of 200-500 years. The dam is a concrete arch dam, and the main flood discharge facility is the crest spillway. In order to prevent flood overtopping and scouring of the downstream dam toe, the crest spillway and the stilling basin immediately downstream of the dam are designed according to the maximum possible flood.

(4) Stress analysis of dam body should be carried out strictly. In addition to the stress analysis of the dam body by the test load method and the finite element method, the 1 / 100 scale structural model test is also carried out in ismes laboratory in Italy for mutual verification.

(5) Flood discharge facilities with the function of emergency discharge and lowering of reservoir water shall be arranged. The bottom sill elevation of the inlet of the scouring channel and the spillway tunnel is 100 m, which is 70 m lower than the normal water level. These two lower flood discharge facilities can discharge half of the reservoir water in one day in case of emergency. Therefore, even if the dam is damaged, the flood waves will not threaten the lives and property of the downstream residents.

Dam construction

The project started in August 1979 and was completed in June 1987. During the construction period, in order to solve the serious water shortage problem in the greater Taipei area in advance, the upstream retaining dam and the dam under construction before the end of December 1983 and June 1984 were respectively used for initial water storage. The water level was controlled by the gate set at the entrance of the diversion tunnel to supply water to Taipei in advance, so as to alleviate the water supply problem in Taipei.

Reasons for building reservoirs

1、 Provide tap water and irrigation water for nearby areas.

2、 Hydroelectric generators on dams are used to generate electricity.

3、 Part of the canal system.

4、 Flood control benefit of reservoir

5、 Runoff regulation of reservoir area and downstream

6、 Other uses include fishing

Disadvantages of reservoir construction

Increase geological disasters in reservoir area

Increasing the frequency of geological disasters in the reservoir area

The construction of the reservoir may induce earthquakes and increase the frequency of earthquakes in the reservoir area and nearby areas. The frequency of landslides, landslides and debris flows will increase in mountainous reservoirs because the lower parts of the mountains on both sides will be immersed for a long time in the future.

It will cause sediment deposition in the reservoir area

Due to the interception of the dam and the influence of backwater in the tail area of the reservoir, sediment will inevitably deposit in the reservoir, especially in the dam and the tail area of the reservoir.

Soil salinization in the lower reaches

The continuous irrigation is not enough

Chinese PinYin : Fei Cui Shui Ku