The statements in this article are based on reliable sources and are repeated at the end of this article
If you want to say where the Chinese are most experienced, this water control must be the number one in the row, as early as thousands of years ago, our ancestors have realized the importance of water control. [Floating clouds]
Whether it is the Xia Dynasty in 2200 B.C., or the construction of Dujiangyan presided over by Li Bing and his son in 251 B.C., they all show us the wisdom and action of the ancients.
The contemporary Three Gorges Dam is also hailed as one of the wonders of the world and enjoys a global reputation.
As a modern man-made dam, how long does the Three Gorges last? How has it changed over the years?
If it were to be dismantled at the end of the day, what would be the impact?
01
When the Three Gorges construction project was promoted, the opposition was never small, but it still started to do it in doubt, and the reason has to start from our Yangtze River.
Do you remember the devastating flood of 1998? This is the third major flood in the last century, which has caused disasters in many provinces, affected 223 million people, lost tens of millions of homes, and the number of injuries and deaths is even more heart-wrenching, and the economic losses have reached 100 billion.
The impact of the 1931 floods was even more immeasurable, with the largest number of deaths in a flood on record.
The death toll of that disaster was even unbelievable and unheard of in modern society.
The Yangtze River looks calm on the surface, but when it rains in the summer, how can people not feel frightened by the soaring water level and the accelerated speed of the water?
Under the premise that the flood has taught us a lesson of grief, how to prevent and avoid the recurrence of such events in the future has become the primary task, so the "Three Gorges Dream" that was put forward as early as the time of Mr. Sun Yat-sen has finally begun to advance.
After several years of construction, our Three Gorges Dam was officially completed in 2006.
The United Nations has conducted a survey of some water conservancy projects around the world, and has come to the conclusion that by 2050, tens of thousands of water conservancy projects will reach the end of their life, and I dare not imagine how devastating disasters will occur at that time.
But the name of the Three Gorges Dam was not seen in this list, and many voices began to fill the environment, with some people believing that the Three Gorges Dam must also be "inescapable".
In fact, the Three Gorges Dam was not surveyed by the United Nations at that time, so this is not a partial generalization.
02
The skeleton of the Three Gorges Project is made up of giant dams, massive hydroelectric dams and ingenious locks, and at the heart of it is the world's largest concrete gravity dam, with an unprecedented 16 million cubic meters of concrete.
Concrete gravity dams get their name because they rely on the sheer mass of concrete to withstand water pressure and other loads, maintaining the safety and stability of the dam structure.
Due to the huge amount of concrete used in this type of dam, comprehensive temperature control measures must be taken during the construction process; There is an overflow section at the top of the dam for flood discharge, and there are numerous drainage holes inside the dam body.
The construction of the Three Gorges Dam consumed nearly 28 million cubic meters of concrete and 460,000 tons of steel, and the weight of the entire dam reached 100 million tons.
In the formulation of C100 concrete, materials such as iron slag powder, high-efficiency superplasticizer and silica fume are also added, and this high-grade concrete is usually only used in military engineering.
The construction of the Three Gorges Dam coincided with a humid and muggy climate south of the Yangtze River, with outdoor temperatures soaring to 30 or 40 degrees Celsius under the scorching sun.
The temperature of concrete made in this environment is naturally high, often exceeding 40 degrees.
If the dam is constructed with these hot concrete, the temperature of the core of the dam may surge to more than 70 degrees, and once it comes into contact with cold water, the concrete structure is prone to cracks, leading to the failure of the entire project, and the consequences are quite serious.
Building & Construction experts have come up with an ingenious solution: adding ice to the mixing process to reduce the temperature of the concrete.
This practice effectively overcame the difficulties caused by high temperatures and ensured the quality of the construction of the Three Gorges Dam.
03
As a world-class water conservancy project, the construction standards of the Three Gorges Project are very high, which are not comparable to ordinary military projects.
Not only can it withstand a powerful earthquake measuring 10 on the Richter scale, but it can also stand under the nuclear attack of megaton TNT explosives, and unless it is destroyed from within, there is almost nothing that can be done to destroy the Three Gorges Dam, and the sturdy dam body with a design life of 150 years is a matter of course.
In fact, the construction of the Three Gorges Dam is not unique to China, and the iconic Hoover Dam in the United States is another outstanding example.
For engineering structures such as gravity dams, the end of their life is usually not due to the inability to continue service, but because the long-term operation exceeds the initial design life, or the long-term erosion of the flowing water in the dam body weakens the structural stability of the dam body, and eventually leads to collapse.
It is also possible that the dam may unexpectedly collapse in the event of a natural disaster such as an earthquake that exceeds the dam's designed capacity.
The Three Gorges Dam project, which cost more than 200 billion yuan, is a spectacular project in the history of water conservancy construction in the world.
Since the Three Gorges Dam was officially opened in 2004, hydropower generation alone has brought 100 billion yuan in revenue to the mainland.
It generates more than 20 million kilowatts of electricity, equivalent to the power generation of five Daya Bay nuclear power plants.
At the same time, the Three Gorges Dam plays a role in regulating the flow of water, and the Yangtze River, as an important inland waterway on the mainland, is responsible for water transportation in the east and west.
However, due to the influence of the monsoon climate, the seasonal and annual fluctuations of rainfall on the mainland affect the stability of the waterway, and the establishment of the Three Gorges Dam has effectively solved this problem.
It precipitates sediment in the dam area through water storage function, improves downstream water quality, and at the same time adjusts the water balance in the dry and flood seasons, which improves the navigation of the Yangtze River, and attracts many tourists after the dam is completed.
04
The Three Gorges Project is magnificent and sturdy, with a design life of 150 years, but this does not mean that the Three Gorges Reservoir can operate for so long, and the problem of sediment accumulation in the reservoir may become a major hidden danger.
There is no shortage of discussion on the Internet, with some arguing that the Three Gorges Dam could be at the end of the tunnel in just 50 years due to the limitations of construction materials.
In fact, in order to ensure the safety of the Three Gorges Dam, the designers have arranged 16,252 monitoring instruments in key areas of the dam, such as concrete gravity dams and asphalt core walls, to monitor the safety status of the dam in real time.
The existence of this system means that even if there are signs of age, such as carbonization of concrete, people can repair them using cutting-edge technology to extend the life of the dam.
This means that the dam may not be decommissioned until 2156 from the date it is built, and it could last longer if it is properly maintained.
Some voices have also asked: If the Three Gorges Dam really needs to be dismantled due to various factors, then how should we face the possible consequences of the demolition?
In fact, we can find inspiration in the history of the Fengman Dam, which has been in use since it aged in 1988 and has been used, repaired and strengthened over the years, and has cost far more than a new dam.
In 1988, half a century of wind, frost, rain and snow made the Fengman Reservoir show its old state under the combined action of weathering, severe cold and erosion.
The dam surface of the reservoir has been severely damaged, softening and falling off.
The damage of 1,300 square meters on the upstream side and the 6,100 square meters on the downstream side irrefutably tell us that there is not much left of the Fengman Reservoir.
We have given it a new lease of life through continuous reinforcements and repairs, but it was also officially demolished a few years ago and a new dam was built nearby.
In the same way, the actual life span of the Three Gorges Dam will surely exceed our expectations under human care.
05
Although we try to maintain it as much as possible, the Three Gorges Dam will still have an end of its life cycle, and what if the Three Gorges Dam reaches the point where it cannot be repaired?
In fact, we can rest assured that although the construction of the Three Gorges Dam is not a one-time project, the mainland's technology in the construction and maintenance of dams and other large-scale projects has been perfected.
Even if the dam does need to be replaced in the distant future, we have the confidence and ability to choose a new site near the original dam and start new construction to build a new Three Gorges Dam to continue to provide safety for the residents of the middle and lower reaches of the Yangtze River, and then the old dam can be safely dismantled.
We must first realize that the removal of the Three Gorges Dam will not directly cause flooding in the lower reaches of the Yangtze River.
Because the regulation of the Yangtze River's water volume is not the sole responsibility of the Three Gorges Dam, there are 25 large hydropower stations embedded in the mountains of the upper reaches of the Three Gorges, including the well-known Baihetan, Wudongde, Xiluodu and Xiangjiaba.
These hydropower stations are located on the main road of the Yangtze River, and they play a significant role in regulating the water volume of the Yangtze River.
In addition, about 38 kilometers below the Three Gorges Dam, stands Gezhouba, known as the "first dam of the Yangtze River".
With a height of 47 meters and a total storage capacity of 1.58 billion cubic meters, Gezhouba has sufficient flood control capacity to ensure the safety of nearby areas.
Even if the Three Gorges Dam is gone, we still have some control over the amount of water in the Yangtze River basin.
What's more, we are fully capable of planning and building a dam in advance in the upper reaches of the Three Gorges that is comparable to the function of the Three Gorges Dam.
So don't worry about these problems, whether it is the maintenance now or the maintenance value is not high in the future to rebuild nearby, basically will not have an impact on our lives, after all, today's continent is famous in all aspects, especially infrastructure, the world.
Reference Sources:
People's Daily - January 1, 2021 Report on "Withstanding the Triple Test, the Three Gorges Power Station Sets a World Record for Annual Power Generation".
China Economic Weekly - July 16, 2020 on "How much pressure is the Three Gorges Dam on the Yangtze River Basin?" Will the dam burst? ".
CCTV News - August 19, 2020 About "Shock! The Three Gorges Dam opened 10 holes for flood discharge, and the role is very critical."