It's just a rumor, so there's no way the breakdown is real. Hi, it's time for the dam log.
It is well known that this year's rainy season has been unusually wet and caused considerable damage in Kumamoto Prefecture, but in China, as in Japan, rivers have been overflowing here and there due to the continuous heavy rains. Our hearts go out to all those who have suffered in both Japan and China.my deepest sympathyAt the same time, we sincerely hope for the earliest possible recovery and that everyone will be able to return to their daily lives as soon as possible.
The rumors of the collapse of the Three Gorges Dam, one of the largest dams in China, have been making the rounds on the Internet for some time now.
This was the result of the mass media (especially Taiwanese and anti-Chinese media) all agitating for the possibility of the Three Gorges Dam to break. In response, Japanese media also wrote articles about it, and so-called YouTubers posted about it, resulting in the spread of rumors on social networking sites as well. (The order may have been social networking sites first.)
So, as a dam enthusiast, I would like to verify, albeit briefly, whether this rumor is true. The best way to be sure is to go there and see it with my own eyes. Unfortunately, however, the new coronavirus is still raging around the world, so it is not possible for me to visit the site.
Also, the rumors are invariably interspersed with political talk. That would be true too. This is a country that buries trains in the ground whenever there is a train accident and poses a military threat to neighboring countries, including our own country, Japan. It is tempting to follow up on these rumors.
However, dams are a universal civil engineering infrastructure. It should not be so easy to break a dam. Therefore, I would like to summarize the results of my research based on feature articles in past issues of Dam Nippon Monthly and as much research as I could find on the Internet, without discussing politics at all.
I will indicate the prerequisites for writing the article.
- I'll leave all political talk out of it.
- Don't conclude gossip.
- I myself don't support the CCP, and of course I'm not a party member.
I would like to say this last part especially strongly. I am a Japanese who was born and lives in Japan, and I have never been to China in my life. In fact, when I was working as a server administrator about 15 years ago, I was hacked many times from China, so I do not have a very good impression of China.
There are other places in the text where the phrase "there were people saying" is used, but this basically refers to statements made on social networking sites. Although we should probably embed social networking posts or take screenshot images for evidence, we use this expression because it is not intended to be a personal attack.
Please note that if anyone who believes that the Three Gorges Dam is distorted or broken reads this article and submits a comment, please submit it with numerical and scientific evidence, not based on Internet rumors. Please be aware that if your comment is based on a rumor, we will delete it.
- Basic Knowledge of the Three Gorges Dam
- Is it true that the levee is distorted?
- Are the distortions allegedly admitted by the Chinese government true?
- Is it true that they don't regulate flooding because they are dedicated to power generation?
- Is it true that you only generate electricity to sell and make money?
- Is it true that cracks and fissures are developing?
- Is it true that the ground of the Three Gorges Dam is limestone and weak?
- Is it true that the Three Gorges Dam will be overturned?
- Finally.
Basic Knowledge of the Three Gorges Dam
Since some people may not be familiar with the Three Gorges Dam in the first place, we would like to explain it as a basic knowledge. The dam specification table often appears on this site, but it has been slightly rearranged because the notation may differ between Japan and China.
| Location | Sanduping, Yiling District, Yichang, Hubei Province, China |
| River Name | Yangtze River (Yangtze River) |
| Objective | F (flood control, agricultural disaster prevention) P(Power generation) *Other water transportation is also a part of the project. |
| Model | G(gravity-fed concrete dam) |
| Bank height | 181m (Japan Grand Dam Conference) |
| Bank length | 2,309.5 m (China Grand Dam Conference) |
| Dam volume | 16,000,000 m3 (dam handbook) |
| Total storage capacity | 39,300,000,000 m3 (China Grand Dam Conference) |
| Flood control capacity | 22,150,000,000 m3 (China Grand Dam Conference) |
| normal level of water supply | EL.175m (dam Japan) |
| Flood stage limit water level | EL.145m (dam Japan) |
| Year of launch | 1993 |
| Year Completed | 2009 |
The height of the embankment is described as 185m in some places, but according to the PDF document of the Great China Dam Conference, 185m is described as "crest elevation", so it is not the height of the embankment, but the height of the embankment.Ceiling elevation(EL).
Is it true that the levee is distorted?
First of all, this is a screenshot image of the "Google Earth photo shows the Three Gorges Dam distorted" which has been said for over a year.
The following image is the current (7/27/2020) Google aerial photo of the Three Gorges Dam. The distortion of the image has now been corrected. 3D images, but flat images, are originally projected in the center of the lens, so the difference in distance between the center of the lens and the object causes a misalignment. This is called ortho-rectification, and it is necessary to correct the image to one with no misalignment as if it were viewed from directly above. In the past, aerial photographs were simply not processed properly.
Previously, Google's aerial photos had distortions here and there, but these have now been corrected at quite a few points. Still, there are some areas where the correction has not caught up. The image below is an aerial view of a portion of the Seto Ohashi Bridge as seen on Google as of 7/28/2020, but it is quite distorted. However, we have not heard of any problems with the bridge itself.
The reason for this is that the Seto Bridge is a distortion of the image and the Three Gorges Dam is an actual distortion of the image. (The image below is blocked and the text is faded.)
Above all, China Telecom, a local telecommunications company, has been providing real-time transmission to the Central China TV (CCTV) video platform, Central View Frequency, so that the current status of the Three Gorges Dam can be seen at a glance.
and in addition to thatright bank (shore)The video is distributed from various angles, downstream and upstream. The following video is a screen shot video of each angle that I took, edited, and connected.
As far as I can see, it doesn't look distorted like it does on Google Earth, much less like it's breaking or about to break.
'This is footage from a few months ago!' Some people seem to be saying that, but I have been watching daily and there have been no changes or signs of deformation of the levee for a long time, and I have confirmed that the video matches the local weather conditions from looking at Windy and other sources. Thus, nothing like David Copperfield's illusions.
Come to think of it, there were times when the resolution was temporarily lowered, perhaps due to a deteriorating communication environment, which only made it look as if some of the cranes and power lines had disappeared, but they're covering it up! It's a fake video! Some people said.
Some people say that the live-streaming videos and the social networking videos from the field described below are CG or composite, but anyone who can produce such videos using CG or compositing must have received a lot of offers from Pixar, Polygon Pictures, and other prominent CG production companies by now.
If you watch the video calmly, you can see this, but it seems to be filtered by the Chinese Communist Party and interpreted by your brain in a way that suits you.
Are the distortions allegedly admitted by the Chinese government true?
Various media outlets distributed news of the Chinese government's supposed admission of the above distortion.
The weight of the water seems to have distorted the concrete dam, and the official Chinese media and the Chinese government have acknowledged this distortion.
Nico Nico News
I thought what you are saying is that the video shows no distortion, but I believe this is a mistranslation or misinterpretation. In fact, the dam does not distort, it deflects. It is possible that this "deflection" was misinterpreted as "distortion.
What this means is that the embankment of a dam is affected not only by water pressure but also by temperature and other factors, causing it to deflect several to several dozen centimeters, depending on the dam. The graph below shows the amount of deflection, with the vertical axis indicating the reservoir level and the horizontal axis indicating the amount of deflection.
A dam has a variety of measurement devices, but the device used to measure "deflection" is called a plumb line. Basically, deflection moves back and forth throughout the year, but when there is an abnormality in the embankment, the graph is obviously "completely different from usual," so the values are measured periodically at the dam.
While there are some uncertainties regarding the detailed measurement conditions at the Three Gorges Dam, it is common knowledge that the embankment itself deflects, and it is quite possible that "deflection" was mistakenly recognized as "distortion".
The Shonai River Office of the Ministry of Land, Infrastructure, Transport and Tourism recently tweeted this. I think it is quite easy to understand about plumb line and deflection.
Incidentally, "deflection" may be called "strain" in some dams.
Is it true that they don't regulate flooding because they are dedicated to power generation?
As mentioned earlier, the purpose of the Three Gorges Dam is flood control. The Three Gorges Dam has power plants on both the left and right banks of the embankment, and the center section is the flood discharge section.
The flood discharge section has the cross section shown in the figure below, with a surface hole near the top of the embankment (crest gateThe 22 gates are deep pits around the midsection (conduit gateThere are 23 gates, each of which is set at an alternating distance from the other.
The pictures and videos in the news footage show the water flowing out of the conduit gate. In other words, this is a situation where flood control is in progress. Therefore, it is a lie to say that the Three Gorges Dam does not regulate floods.
In addition, the water level, inflow and discharge at the Three Gorges DamChangjiang Hydrological NetworkThe data was disclosed on the website of the giant bulletin board 5ch, and the volunteers of the giant bulletin board 5ch scraped the data andProcessed and published as a hydrographThe company has been
The fact that the discharge rate is changing in this case clearly indicates that flood control is being carried out.
Incidentally, some people have been complaining that the data is sometimes missing and that "they are covering it up! However, missing data is a common occurrence at water level stations in Japan, and as shown in the graph, it is clear that data can be obtained by shifting the time, so it should be ignored.
Is it true that you only generate electricity to sell and make money?
As mentioned above. Since flood control is provided, it is not possible to only generate electricity.
On the contrary, some people made the mysterious statement that they were not generating electricity, see the video below.
This is a nighttime video of the Three Gorges Dam. The water in the foreground looks like the movement of "water after it has worked at the power plant," which is often seen in Japanese dams.
The reason for this movement is that water discharged from the power plant of the Three Gorges Dam is discharged underwater. The figure below shows a cross-sectional view of the power station section, with the left side on the lake side of the dam and the right side downstream. Water taken in from the dam lake is used for power generation through a water wheel in the building downstream, and is then discharged underwater downstream. This discharged water flows slowly as shown in the video above.
Is it true that cracks and fissures are developing?
None of this raises eyebrows when there are no field photos, but I believe the cracks are hair cracks less than 0.2 to 0.3 mm wide and the cracks are joints.
Hair cracking is a phenomenon that is bound to occur as long as the product is concrete, and its presence does not immediately affect the quality or structure of the dam.
In addition, according to Dam Nippon, the main body of the Three Gorges Dam has joints in six sections from 17 to 21 meters using a vibrating cutter. Joints are like rail joints on a railroad, which rather prevent cracks by reducing stress by allowing expansion and contraction of the concrete to occur within an acceptable range.
Incidentally, the photos in this Dam Japan are construction photos at the Three Gorges Dam.
Is it true that the ground of the Three Gorges Dam is limestone and weak?
It is a mystery where this information came from, but it is a rumor that is often mentioned on social networking sites and video sites.
According to Dam Japan, the granite exposed in the area of the Three Gorges Dam site is also granite. The basement rock is also composed mainly of medium- to coarse-grained granite, megacrystalline rock (pegmatite, megacrystalline granite), pyroxene and veins, and the two are always in close contact with each other.
Nowhere is there any mention of limestone, but rather it seems to be of good quality.
The geological conditions are favorable, and the high-quality rock body accounts for about 98% of the total.
However, weathering and unloading may have increased permeability by partially spreading into faults and fracture planes, and there were also rock bodies with medium to large permeability within the microweathered zone, mainly within the 20 m depth range, which may become water loopholes after water storage.
However, this problem is solved by grouting, described below.
Is it true that the Three Gorges Dam will be overturned?
You may have seen images of ocean breakwaters being overturned by tsunamis.
However, the way breakwaters are built is completely different from that of dams. In addition, the amount of concrete used for the main body is completely different, and the environment and way of thinking of each is completely different, so there is no comparison to be made.
In addition, the foundation rock is grouted with curtain grouting, in which cement milk is injected in a curtain-like pattern into the gaps between the bedrock. This improves the impermeability of the dam lake and prevents water pumping.
According to Dam Nippon, the construction journals and other documents contain very detailed descriptions of the installation of the curtain grouting and consolidation grouting, which are summarized as follows.
It would be unthinkable in Japan to see such detailed grouting work being done on such a hard dam site, and I could sense China's enthusiasm for the Three Gorges Dam, which is a prestigious project.
From Dam Nippon No. 842 "Literature on the Construction of the Three Gorges Dam, Part 14: Body Works (4)
Japanese dam experts have observed that the dam is more solidly constructed than in Japan.
Finally.
I summarized this and that, but just the other day a Chinese person who went to the Three Gorges Dam to cover the event reported it almost in real time on Twitter. This is it, this is what I've been waiting for! I was so happy to see it.
I think it can all be summed up in this video. It is clear from the fire that it is not distorted, it is not broken, and it is not about to break.
This person has also been active in interviewing engineers of the Three Gorges Dam. In the case of dams in Japan, it is often said that the downstream of a dam was submerged because the dam released water, but this was not caused by the dam releasing water but by flooding, and the heavy rainfall in China this time was caused by the fact that the rainfall area was quite extensive to begin with. I think the report is easy to understand and compact.
In addition, they also tweet about lodging and dining in the vicinity of the Three Gorges Dam, which may be helpful when visiting the Three Gorges Dam.
Incidentally, it seems that "if you upload photos taken at the Three Gorges Dam on SNS, you will be detained by the local police" was also a rumor, and this A-chan also took a clear stand, saying, "That's not true at all. All et cetera related to China may consist of rumors. In a sense, that is an unavoidable aspect, but I would like to look at it from a clear, unfiltered perspective.
I believe that the Three Gorges Dam was built with national prestige, but above all, I believe that it was built with the souls of civil engineers. In addition, although the construction is being carried out solely by China, many technologies and theories from advanced dam countries, including Japan, have been appropriated and diverted. In fact, some of the construction machinery is also American. Geological surveys were conducted by the Soviet Union before the war and by the U.S. immediately after the war.
If this should happen, it could shake the very foundations of dam construction, or civil engineering in general, not only in Japan but throughout the world. That is why we should refrain from making rash statements based on mere rumors.
Anyway, the Three Gorges Dam is not distorted. It has not burst. Nor is it likely to break.
That is all.
Comment
Because it's China.
This makes most of the sense, and the suspicion of about 501 TP3T is true.
This article itself is already 3 years old, and people have been saying it will break for over 10 years to begin with, but when in the world will it break?
Isn't it too easy to just say, "Well, it's China.