Discussion on dam water storage project

The Three Gorges Dam is the largest dam in China, with a total length of 2,308 meters and a height of 1.85 meters, equivalent to 60 stories, and a storage capacity of about 39.3 billion cubic meters. The electricity generated by the Three Gorges Dam can be used by 60 million people in China. The actual height of the Three Gorges Dam is185m.

I. Introduction to the Three Gorges Dam

The Three Gorges Dam is located in Sandouping Town, Yichang City, Hubei Province, China, 38 kilometers away from the downstream Gezhouba Water Control Project. It is the main project of the Three Gorges Hydropower Station, the core landscape of the Three Gorges Dam tourist area, the eastern end of the Three Gorges Reservoir and the largest hydropower project in the world.

The Three Gorges Dam project consists of the main building and diversion project, with a total length of about 3,335 meters and a total investment of 95.46 billion yuan. 65,438+0994,65,438+04 officially started in February and was successfully completed on May 20, 2006.

The normal water level of the dam of Three Gorges Hydropower Station is175m, and the reservoir length is 2335m.

Second, the design of Three Gorges Dam

The Three Gorges Dam is a concrete super gravity dam. 28 million cubic meters of concrete was used in the dam construction, which is equivalent to putting a solid concrete pipeline with a diameter of 1 m around the equator of the earth.

However, there is a difficult problem to be solved when using concrete as a dam, that is, the material of concrete is cement, water and bone powder, but cement will heat up when it meets water. At this time, the external temperature of the produced concrete has cooled, but the internal temperature is still very high. When the internal high temperature concrete dissipates heat, it will cause cracks outside the dam.

In order to solve this problem, people used to divide the dam into several small pieces, and then put the cracks together with concrete after each piece of concrete dried.

When the Hoover Dam was built, the designer adopted the method of water cooling, and built many pipes inside the dam to let low-temperature water flow through the dam. After the dam is completed, cement is poured into these pipes to ensure that the dam will not crack.

The Three Gorges Dam in China did not take such measures. Instead, the aggregate, building materials and sand were cooled first, then the cement was put in and mixed, and a lot of ice cubes were put in to cool down during the mixing process. In addition, during the construction process, the dam also used a spray truck to continuously spray water mist to the construction site. This is because water mist can reduce the direct sunlight on building materials, thus making the temperature of materials rise slowly.

When the temperature inside and outside the dam is consistent, the strength of the dam can support the scour of the flood and will not fall apart after being hit by the flood.

In order to prevent water from washing away the dam, people later built a slope in front of the dam and added a baffle in front of it.

At this time, when the water at the top of the dam flows downwards, it will flow down the slope and form a tumbling vortex after encountering the baffle, which consumes the potential energy of the water, so that even if the water falls downwards again, the energy is not high and the foundation of the dam will not be damaged.

So is the Three Gorges in China. There is something like a baffle in the spillway of the Three Gorges Dam. When the Three Gorges Dam needs to be opened for flood discharge, engineers will open the corresponding gates at this time, and the water will pour down the spillway, and then meet the slope like a baffle, forming an upward jet and forming small water droplets in the air, so that the water potential can be reduced without destroying the dam bottom.

If the Three Gorges is flooded and the flood overflows the dam crest, the water overflowing the dam crest will also flow downstream through this design, and the dam will not be washed away.