Will Baihetan Hydropower Station be accessible after its completion?

In the modern society with the rapid development of science and technology, the power generation modes in China are more and more diversified, and hydropower, wind power, nuclear power and photovoltaic power generation are all good clean energy sources.

Thanks to China's rich topography, hydropower is gradually popularized in China, and the location of hydropower stations is generally in places with steep terrain and rapid water flow.

Originally, these topographical factors more or less restricted the agricultural development in China, but after the construction of hydropower station, they became a great weapon to help China reuse resources.

From 1994 to 2009, it took China 15 years to build the Three Gorges Hydropower Station, the largest hydropower station in the world. This is the largest project in China's history, which has played a very important guiding role in the Yangtze River shipping.

Besides the Three Gorges Hydropower Station, there is a world-class hydropower station under construction in China.

This hydropower station spent a huge sum of 654.38+08 billion yuan and won six world firsts. Known as one of the most difficult hydropower projects in China and even in the world. It's Baihetan Hydropower Station.

The planning time of Baihetan Hydropower Station alone took 70 years, which can be said to be full of twists and turns and ill-fated. Why?

As early as 1950s, the plan of building Baihetan Hydropower Station was put forward. 1958, with the technical assistance of Czech and Slovak experts, China planned to build a super-large hydropower station in Baihetan.

196 1 year, due to the breakdown of Sino-Soviet relations and China's "three-year difficult period", this plan was once shelved.

1965, the construction plan of Baihetan Hydropower Station was incorporated into the national development plan again. Unfortunately, after Baihetan Hydropower Station was included in the development plan, it encountered the Cultural Revolution at 10, and the construction plan ran aground again.

In 2002, the state officially approved the construction plan of Baihetan Hydropower Station. However, due to the environmental pollution near the hydropower station and the Wenchuan earthquake in 2008, the construction of Baihetan Hydropower Station has not started.

In this way, the construction of Baihetan Hydropower Station was not officially started until 20 1 1. Now, the construction of Baihetan Hydropower Station is finally coming to an end.

The first batch of units is expected to be put into production in July 20021year, and all units are expected to be completed and put into production in July 2022. By then, a hydropower station that has been planned for nearly 70 years will appear in front of people.

Besides the long planning time, the construction of Baihetan Hydropower Station is also the most difficult in the world. What are the characteristics of Baihetan Hydropower Station and why is it so difficult to build it?

First, the complex terrain of Baihetan increases the difficulty of construction.

As mentioned above, due to the topography of our country, hydropower has great development space in our country. In the west of China, mountains and plateaus are dominant, and mountains are endless, such as Hengduan Mountains and Qilian Mountains.

However, rapid water flow will be formed under such terrain drop, which is an important condition for hydropower development. Let's take the completed Three Gorges Hydropower Station as an example.

The Three Gorges Hydropower Station is located in Xilingxia section of Yichang, Hubei Province. It is surrounded by Xiling Mountain, from Xiangxi in the west to Nanjinguan in the east. The peaks on both sides of the strait go straight into the sky, with great differences in topography, large water flow and rapid water flow.

Both sides of Baihetan Hydropower Station and Three Gorges Hydropower Station have the same effect. Baihetan Hydropower Station is located in ningnan county, Liangshan Prefecture, Sichuan Province and Qiaojia County, Zhaotong City, Yunnan Province, relying on the water of Jinsha River.

The whole Jinsha River is 348 1km long, with a drop of more than 3,300 meters. With large river flow and rapid water potential, it fully meets the requirements of building hydropower stations and is an excellent site for hydropower generation.

However, although the steep terrain provides a nearly perfect prerequisite for hydropower generation, it also means that construction workers need to face no small challenges.

The mountains on both sides of Baihetan Hydropower Station are as high as 3000 meters. It is obviously extremely difficult to drive the engineering vehicle up such a towering cliff. But if the construction vehicle can't drive up, how can it be constructed?

With the experience of successfully building the Three Gorges Hydropower Station, designers quickly thought of a solution. They set up a steel frame between the two mountains and pulled up the rope. In this way, they transported the concrete mixer from the air to the corresponding position.

In order to prevent the concrete from hardening, the mixer truck has to keep working in the air, which is very dangerous and needs accurate calculation and careful control, otherwise a slight carelessness will lead to a major accident.

Moreover, the area of Baihetan Hydropower Station is too large, and the required concrete pouring volume is 865,438+10,000 cubic meters, which is less than half of the Three Gorges Hydropower Station.

Ordinary cement will heat up when it meets water, which will cause the dam to crack rapidly and affect the safety and service life of the dam. Therefore, it is not feasible to build Baihetan Hydropower Station with ordinary cement.

In order to solve this problem, Baihetan Hydropower Station adopted a low-heat portland cement, also called low-heat cement. This kind of geothermal cement has slower heat release rate and lower alkali content than ordinary cement, which can effectively reduce the risk of large-scale cracking of dam concrete.

It can be seen that Baihetan Hydropower Station is not only difficult to construct, but also very particular about material selection, just like "piling wood". Once there is a problem in the middle, it will face the risk of overall collapse, and there is no room for carelessness.

Secondly, Baihetan Hydropower Station adopts concrete hyperbolic arch dam, which is a world-class super-high arch dam.

First of all, let's briefly explain what an arch dam is. Dams are mainly divided into arch dams and gravity dams, and the Three Gorges Dam adopts gravity dams.

In the upstream of the dam, the water pressure is higher and the downstream water pressure is lower. With the increase of the height difference between the two sides, this pressure difference can reach as much as ten atmospheres.

In order to ensure the safety of the dam and make it work normally, it is necessary to balance this huge pressure difference.

Gravity dam mainly relies on the pressure generated by its own weight to offset the water pressure, while arch dam uses its own special curved surface to transfer the water pressure to the rock mass on both sides, so that the rock mass can resolve this huge pressure difference, so that the pressure acting on the dam is naturally small.

Then why doesn't Baihetan use gravity dam like the Three Gorges Hydropower Station? This is because there is a big gap in Baihetan Hydropower Station. If we have to use a gravity dam, we need a particularly large gravity dam, which is not allowed by actual conditions.

Coincidentally, the water surface of Baihetan in Jinsha River is narrow, and the hard rocks on both sides also provide a good foundation for the use of arch dams, which can bear the water pressure transmitted by arch dams. After comprehensive consideration, arch dam naturally becomes an inevitable choice.

So what is a hyperbolic arch dam?

Simply put, the dam is hyperboloid, so the stress on the dam is more scientific. Especially for the V-shaped valley like Baihetan, the hyperbolic arch dam can not only effectively save dam materials, but also improve safety, killing two birds with one stone.

Thirdly, the underground cavern of Baihetan Hydropower Station is complex, with a cost of 654.38+0.8 billion yuan.

There are eight hydropower stations in the upper reaches of the Yangtze River in China, among which Jinsha River is particularly important. For this reason, China has also made a polar planning map of Jinsha River hydropower.

In this plan, from the Tanggula Mountain in the southwest to Yushu, to the Tiger Leaping Gorge and to Yibin, the altitude once dropped, from 6622 meters to 4200 meters and then to 1800 meters, and finally Yibin was only 800 meters. It is this huge gap that has created a huge water resource.

But it is also because Baihetan Hydropower Station is huge and needs a lot of construction equipment. Baihetan is located in the deep V Gorge, with steep terrain and little space for construction equipment.

So we can only choose to dig underground caves to store construction equipment. Baihetan underground cavern is huge and complex, with an amazing amount of excavation, reaching 25 million cubic meters, with a height of 88.7 meters and a top arch span of 34 meters. It is the largest underground cavern in the world.

Some people may think: How difficult is it to dig underground caves? Isn't it just digging a hole to put things in?

It's not that simple. We can think of the underground cave as a plastic bag full of things. It is difficult for us to take out the contents and keep the plastic bag in its original state.

In the process of underground cavern excavation, in order to ensure the layout and safety of the cavern, designers also adopted three-dimensional design and numerical simulation technology. With these technologies, China has also gained many technological innovations.

After completion, the distance between underground caverns of Baihetan Hydropower Station will add up to 217km, which is equivalent to the distance from Wuhan to Jingzhou.

According to incomplete statistics, Baihetan Hydropower Station has spent more than180 billion, so is it worth it? Did China miscalculate the benefits of Baihetan Hydropower Station and make a loss-making business?

In fact, although the construction of Baihetan Hydropower Station in China has spent a lot of manpower, material resources and financial resources, it is definitely a success.

First of all, Baihetan Hydropower Station is located at the junction of Asia-Europe plate and Indian Ocean plate. We all know that plate collision will lead to geological disasters, which is extremely unfavorable to people's lives and property safety.

Therefore, in the early stage of the construction of Baihetan Hydropower Station, China has resettled the surrounding residents. After these residents emigrated, their income increased and their quality of life improved. The most important thing is to avoid serious geological disasters at any time.

From this point of view, Baihetan Hydropower Station has become the "protector" of soil and water.

Secondly, the Jinsha River itself has a large gap and is not suitable for ships to pass.

With Baihetan Hydropower Station, not only hydropower can be utilized, but also sand can be stopped, flood control can be carried out, navigation conditions in the downstream port area can be improved, and everything can be made the best use of, giving Jinsha River a "useful place".

Finally, as a hydropower station, the reason why the country is willing to spend "blood" on it is naturally that it has a crush on its hydropower generation capacity. Baihetan Hydropower Station has the largest single unit capacity in the world, with a hydropower unit of one million kilowatts.

You know, as the largest hydropower station in China, the Three Gorges Hydropower Station has only 700,000 kilowatts, and it is not only the largest single-machine capacity. Baihetan Hydropower Station has installed 8 million kilowatt hydropower units on the steep river bank.

Under this configuration, Baihetan Hydropower Station will generate about 70 billion kWh of electricity every year after it is fully put into operation. If such a huge amount of electricity is used for production, it will bring huge economic effects to China, even if Baihetan Hydropower Station is a "printing machine".

Baihetan Hydropower Station, as a major project in the development of the western region, can also "transmit electricity from the west to the east" after its completion, which has a high economic development capacity.

We should know that Baihetan Hydropower Station is located in the west of China, while the real "big power users" in China are basically distributed in the east.

At this time, how to transport power resources from the west to the east is the most important, and the emergence of Baihetan Hydropower Station can just solve this problem.

At present, the 800 kV DC UHV transmission project from Baihetan to Suzhou has started construction, with a total length of 2,088 kilometers.

Through Sichuan, Chongqing, Hubei, Anhui and Jiangsu, it can transmit 30 billion kWh of electricity every year after completion. It can solve the problem of uneven distribution of resources in China and fully improve the utilization efficiency of resources in China.

To sum up the above points, we can easily draw a conclusion: China spent all its money on the construction of Baihetan Hydropower Station, not "stupid people spend more money", on the contrary, it reflected China's long-term strategic vision.

Baihetan Hydropower Station is not only the first large-scale use of low-heat concrete; Underground caves are the largest; The hydropower station with the largest single unit capacity has the highest seismic parameters of arch dams. The water surge chamber is the largest; The largest hydropower station without spillway tunnel has won six world firsts, which also reflects China's strong infrastructure capacity.

Baihetan Hydropower Station has amazed the world before it was built. I believe that on the day it is completed, the world will once again look at China with new eyes. After all, this is China that our Chinese sons and daughters are proud of.