As the largest water conservancy project in the world, the economic benefits of the Three Gorges Dam in water conservancy, power generation and shipping are obvious to all.

But there has always been a question lingering in people's minds, that is, the Three Gorges Dam is 185 meters high, which directly intercepts the Yangtze River. The total drop between the upstream and downstream is 113 meters. How does it allow ships to and fro on the Yangtze River to sail freely Woolen cloth?

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How Ships Pass Through the Three Gorges Dam

In fact, as early as 214 BC, during the construction of the Ling Canal in the Qin Dynasty, they encountered the problem that ships could not pass due to the water level drop. Later, people built a tool called a ship lock on the Ling Canal. This problem was solved.

After the 20th century, due to the development of rivers and the development of shipping, the number of ship locks in the former Soviet Union, the United States and Western European countries has also increased. So what kind of tool is this ship lock?

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what is a lock

The so-called ship lock is actually a box-shaped navigation building. By filling and releasing water into the channel controlled by gates at both ends, the ship can smoothly pass through the dam.

However, to use this method, the dam must have a concentrated water drop in the stepped longitudinal section. We also mentioned before that the water surface drop of the Three Gorges Dam is as high as 113 meters, so it is more suitable to use the method of building ship locks to solve the problem of ship navigation.

After comprehensively considering various factors such as construction cost, technical difficulty and operation management, the Three Gorges construction team flattened 18 hills, and finally built a 6,442-meter-kilometer class 5 ship lock in the hill on the left side of the dam , of which the main part of the lock is 1.6 kilometers, and the approach channel is 4.8 kilometers.

And for ships of different tonnages, we have also designed two different ways of crossing the dam, in simple terms, "big boats climb stairs" and "small boats take stairs".

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Two ways to cross the dam

If a ship's tonnage exceeds 3,000 tons, then it needs to "climb the stairs", and the "staircase" here actually refers to the five-level lock.

If the ship is coming from downstream, the staff will lower the water level of the fifth lock chamber to the same level as the downstream water level, and then open the gate to allow the ship to enter the lock chamber.

Next, the staff will close the gate, open the water delivery system to release the water to raise the water level in the lock chamber, and the ship will be raised as the water level rises. When the water level is at the same level as the water level in the lock chamber No. 4, the staff will open the lock chamber No. 5. the gate, the ship can enter the upper lock chamber.

The data shows that it only takes two and a half hours from entering the lock chamber to entering the upper reaches of the Yangtze River. If the ship is traveling from upstream to downstream, it only needs to reverse the whole process.

What is even more surprising is that the waterway of this five-level ship lock is actually divided into two, the upstream approach channel is 2113 meters, and the downstream approach channel is 2708 meters, which means that the upward and downward ships will not interfere with each other, so saving a lot of time.

If the type of ship belongs to tourist ship, some cargo ships, and large passenger ships under 3000 tons, then it must choose to take the ship lift to pass through the dam.

Relevant information shows that the total length of the Three Gorges ship lift is 5,000 meters, the maximum lifting height is 113 meters, and the lifting weight can reach 15,500 tons. When a ship takes a "dam elevator".

That is to say, when the Three Gorges ship lift moves from the downstream to the upstream of the dam, it will first drive into the ship-carrying compartment, then the shipping-carrying compartment will rise to the level of the upstream reservoir and then stop, and finally the staff will open the shipping-carrying compartment. The upstream gate, when the ship enters the upper channel of the Yangtze River, is the end.

Compared with climbing the fifth-level ship lock, it only takes 40 minutes to enter the upstream channel by "taking the elevator" to complete the "climbing" of the 113-meter-high building. Because of this, the ship lift is vividly compared. into a "ship elevator".