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Thread: Three Gorges Damn might fail

  1. #1
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    Default Three Gorges Damn might fail

    If it does, it will impact over 400 million people downstream:

    https://www.ntd.com/chinas-three-gor...ns_478009.html
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    Default Re: Three Gorges Damn might fail

    Wasn't it predicted to be failure prone from its inception?

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    Default Re: Three Gorges Damn might fail

    Wang said after a serious flood in 1998, China’s then-premier hired Western experts to assess the quality control of the build. The experts said the steel bar welding of the dam didn’t meet with standards.

    Chinese workers were unhappy and said the Western expert’s criticism was racial discrimination. But the criticism came too late.
    I wonder if the subsequent damage downstream will be called "racist", too?

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    Default Re: Three Gorges Damn might fail

    Damn that dam.

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    Default Re: Three Gorges Damn might fail

    Hope it holds.
    I was born on a wooden boat that I built myself.

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    Default Re: Three Gorges Damn might fail

    That's crazy. 400 million humans potentially in harms way.
    Stay calm, be brave....wait for the signs. Possibly precariously prevaricating.
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    Default Re: Three Gorges Damn might fail



    Note the structural deformation.



    https://www.organiser.org/Encyc/2020...y-experts.html

    Are there evacuations?

    Or is the government, characteristically, denying that there's a risk?
    Last edited by Chip-skiff; 07-09-2020 at 04:03 PM.
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    Default Re: Three Gorges Damn might fail

    "State experts said the dam had moved a few millimeters, but within the normal safety range."

    Looks like quite a few millimetres…………..

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    Default Re: Three Gorges Damn might fail

    Bad leadership - authoritarian, demogic, laissez-faire, Republican, or what have you - often results in corruption, incompetence, and other forms of dysfunction. For which the governed pay the preponderance of the costs.
    Last edited by David G; 07-09-2020 at 05:31 PM.
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    Default Re: Three Gorges Damn might fail

    Quote Originally Posted by Chip-skiff View Post


    Note the structural deformation.



    https://www.organiser.org/Encyc/2020...y-experts.html

    Are there evacuations?

    Or is the government, characteristically, denying that there's a risk?
    BotB will be along shortly to tell us that structure has already suffered initial failure, with catastrophic failure coming at any time.
    Rattling the teacups.

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    Default Re: Three Gorges Damn might fail

    What the overhead photo shows is that the dam is now longer than when it was built, that is some parts are pulling away from others. Since it was built of rigid materials, that suggests there will eventually be one or more cracks and it will be breached.

    That might be an oversimplification, but I wouldn't bet on the structure surviving for a long time.
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    Default Re: Three Gorges Damn might fail

    Quote Originally Posted by Chip-skiff View Post
    What the overhead photo shows is that the dam is now longer than when it was built, that is some parts are pulling away from others. Since it was built of rigid materials, that suggests there will eventually be one or more cracks and it will be breached.

    That might be an oversimplification, but I wouldn't bet on the structure surviving for a long time.
    This is what is known as 'initial failure'.
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    Default Re: Three Gorges Damn might fail

    Quote Originally Posted by oznabrag View Post
    BotB will be along shortly to tell us that structure has already suffered initial failure, with catastrophic failure coming at any time.
    YIKES! Are those 2018 pics real and not doctored?

    EDIT: Uh, nah, looks like the images were distortion in the satellite images. I hope so: https://www.dailymail.co.uk/news/art...ne-rumors.html

    When the dam was built, my thoughts were, well the environmental side of me opposes, however with the periodic floods before it, and the clean power generation, I can understand them building it. I was actually impressed with it, and thought that with the cost of labor there, it would have been built first rate, like the large public works dams constructed during the Great Depression, over-designed. Hoover Dam. Grand Coulee Dam.

    I sure hope the suspicions are wrong, that dam is HUGE, a collapse would be catastrophic.

    Has anyone here seen the movie Force 10 from Navarone (1978)?

    Barnsby : Now, look. Our experts have been studying that bridge for weeks, and they say it'll blow. I don't know where you learned your job, but I'm talking about the best construction engineers in the business!
    Miller : Yes. Well, they're probably experts at building things, whereas I'm an expert at blowing them up, and you can take it from me that one would need a good eight hours to make a decent job on that bridge.
    Mallory : [thoughtfully] Miller, what would happen to the bridge if that central arch were suddenly hit by several million tons of water?
    Miller , Barnsby : Water?
    Mallory : I think we've been talking about the wrong target. Remember that dam we passed by on the way up here?
    Miller : [suddenly all ears] Dam? What sort of dam?
    Barnsby : It's just up the road, about half a mile that way.
    Miller : Well, my dear chap, why didn't you say so before? Oh, I could do a tremendous job on the dam! See, with the dam, you've got your natural elements working for you. It's like having an enormous bath - what have you got to do? Pull the plug!
    Last edited by Bob (oh, THAT Bob); 07-09-2020 at 05:56 PM.
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    Default Re: Three Gorges Damn might fail

    Those overhead shots are scary to say the least. If and when it goes I’m hoping there are lots of cameras in position. Gonna be quite a sight.
    Fight Entropy, build a wooden boat!

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    Default Re: Three Gorges Damn might fail

    epoxy, that’ll fix it

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    Default Re: Three Gorges Damn might fail

    Quote Originally Posted by CWSmith View Post
    I wonder if the subsequent damage downstream will be called "racist", too?
    What an odd thing to say.
    ​"Life is under no obligation to give us what we expect." Irrfan Khan. RIP

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    Default Re: Three Gorges Damn might fail

    This will be the second time the dam has affected millions- the first was when they kicked everybody out to build it, not to mention wiping out some of the worlds most significant archaeology- back to the beginning of civilisation (at least six thousand years, wink grin) Actually 1.6 million years. JayInOz

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    Default Re: Three Gorges Damn might fail

    History of Glen Canyon Dam during peak flood, important details:

    The 1983 floods



    During the El Niño winter of 1982–1983, the Bureau of Reclamation predicted an average runoff for the Colorado River basin based on snowpack measurements in the Rocky Mountains. However, snowfall during April and May was exceptionally heavy; this combined with a sudden rise in temperatures and unusual rainstorms in June to produce major flooding across the western United States.[87] With Lake Powell nearly full, the USBR did not have enough time to draw down the reservoir to accommodate extra runoff. By mid-June, water was pouring into Lake Powell at over 120,000 cubic feet per second (3,400 m3/s). Even with the power plant and river outlet works running at full capacity, Lake Powell continued to rise to the point where the spillways had to be opened. Other than a brief test in 1980, this was the only time the spillways had ever been used.[88]

    At the beginning of June, dam operators opened the gates on the left spillway, sending 10,000 cubic feet per second (280 m3/s), less than one-tenth of capacity, down the tunnel into the river below. After a few days, the entire dam suddenly began to shake violently. The spillway was closed down for inspections and workers discovered that the flow of water was causing cavitation – the explosive collapse of vacuum pockets in water moving at high speed – which was damaging the concrete lining and eroding the rock spillway tunnels from the upper ends of the diversion tunnels, which connect to the bottom of the reservoir.[89] This was rapidly being destroyed by the cavitation and it was feared that a connection would be made to the bottom of Lake Powell, compromising the dam's foundation and causing the dam to fail.[89]

    Meanwhile, snow continued melting in the Rockies and Lake Powell continued to rise rapidly. To delay having to use the spillways, the USBR installed plywood flashboards (later replaced by steel) atop the gates to increase the lake level.[90] Even this additional capacity was exhausted; discharges through the left spillway reached 32,000 cubic feet per second (910 m3/s), and the right spillway was opened to 15,000 cubic feet per second (420 m3/s). At Lee's Ferry, the Colorado River peaked at 97,300 cubic feet per second (2,760 m3/s), which was and still is the highest water flow recorded there since the dam was built.[91] On July 14, Lake Powell reached 3,708.34 feet (1,130.30 m) elevation, a level that has not been exceeded since.[92] Just as it seemed inevitable that the dam would fail, inflows fell and the dam was saved. Upon inspection, it was found that cavitation had caused massive gouging damage to both spillways, carrying away thousands of tons of concrete, steel rebar and huge chunks of rock.[93]

    Repairs to the spillways commenced as soon as possible and continued well into 1984. Air slots were installed at the bottom of each spillway to break up and absorb the shock of the bubbles formed by cavitation. In 1984, the Colorado River basin produced even more runoff than 1983, peaking at 148,000 cubic feet per second (4,200 m3/s) in early June.[94] This time, the USBR had drawn down the reservoir enough that it absorbed most of the early high flows. Nevertheless, Lake Powell rapidly approached the top of the spillway gates and construction efforts were subsequently focused on the left spillway in order to get it in operation in time. On August 12, the left spillway gates were opened, releasing water at a rate of 50,000 cubic feet per second (1,400 m3/s). The spillway was undamaged, proving the worth of the re-engineering and suggesting that Glen Canyon Dam will also be able to hold against future floods with the magnitude of 1983.[95][96]
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    Default Re: Three Gorges Damn might fail

    Glen Canyon Dam is very different to Three Gorges. First, like Hoover Dam, it's an arch dam in a narrow canyon with no provision for spilling water over the dam itself. Second, the spillways are concrete-lined tunnels through bedrock, which is why they were so vulnerable to cavitation at extreme flows. The openings of the tunnels are visible on either side.



    The problem was that the water threatened to overtop the main dam, not massive structural failure, as has been predicted for Three Gorges. The recent problems with the Oroville Dam, an earthfill structure in California, resulted from high flows over the damtop spillway which damaged the poorly-designed concrete structure and allowed water to fall to the side, tearing out massive volumes of soil and rock and undercutting the spillway.



    A structural failure took place when the earthfill Teton Dam in Idaho, started leaking and then breached as the reservoir was being filled.



    I'm not aware of a large concrete dam suffering massive structural failure. Which is not to say it can't happen.
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    Default Re: Three Gorges Damn might fail

    I never thought much of bamboo rebar

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    Default Re: Three Gorges Damn might fail

    Here's another image showing the deformation of the structure. If it was a matter of atmospheric distortion, etc. on a satellite image, the roadways and structures on the banks would show similar distortion. But that doesn't appear to be the case. It looks like the structure is shifting on its foundations, perhaps a differential response to the pressure and weight of the water upstream.

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    Default Re: Three Gorges Damn might fail

    Hate to break it to y'all, but those dam images are either fake, or the unfortunate result of two overlapping images stitched together. It should, perhaps, be obvious that if the dam is actually as badly distorted as those images above claim to show, the dam should already have collapsed.

    This is the current sat image on Google Maps. It was taken this year.
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    Default Re: Three Gorges Damn might fail

    But when this year Oyvind? They've just had thirty eight straight days of rain and the situation is apparently dire. JayInOz

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    Default Re: Three Gorges Damn might fail

    Quote Originally Posted by Chip-skiff View Post
    Glen Canyon Dam is very different to Three Gorges. First, like Hoover Dam, it's an arch dam in a narrow canyon with no provision for spilling water over the dam itself. Second, the spillways are concrete-lined tunnels through bedrock, which is why they were so vulnerable to cavitation at extreme flows. The openings of the tunnels are visible on either side.

    The problem was that the water threatened to overtop the main dam, not massive structural failure, as has been predicted for Three Gorges. The recent problems with the Oroville Dam, an earthfill structure in California, resulted from high flows over the damtop spillway which damaged the poorly-designed concrete structure and allowed water to fall to the side, tearing out massive volumes of soil and rock and undercutting the spillway.

    I'm not aware of a large concrete dam suffering massive structural failure. Which is not to say it can't happen.
    Yes, Glen Canyon is an arch dam, and stronger because of it. But Grand Coulee (which I mentioned earlier), like Three Gorges, is not arched.

    Correct me if I am wrong, but the Oroville spillway failure started with cavitation from high speed flows that ate through the concrete, then spilling over the side. I had wondered about solutions when they rebuild, and the solutions to combat cavitation with the Glen Canyon spillways may apply despite the spillway shapes being completely different, as it is a surface flow effect.

    Whether a dam is designed for spilling over the top or not, when the water gets that high, it spills over the top.

    As I suspected, the images in the story dated 2018 do not appear to be legit. Something about the original image was off to me, one of those fuzzy logic things that you can't place, your mind just tells you something is off, it looked like image distortion.
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    Default Re: Three Gorges Damn might fail

    I was stationed in Taiwan when the thing was first under construction. I got to see the PRC's national propaganda magazine (think Life, but without ads, and all in Mandarin) with articles extolling the virtues of our beloved leader Chairman Mao, with pictures of the progress of the excavations for the dam, and the new modern villages they built for the displaced. We also got to see the CIAs satellite images of the same thing.

    As for the genuiness of these photos, I've no comment, but it is a bit ironic when I remember that in the magazine articles, the pics of the new construction, and also the official pics of the model villages, like the ones built across strait and just outside the mainland portion of Hong Kong, pristine for propaganda value, were doctored, air-brushed, in exaclty the same manner as the Russians, who used to, for pulblished photos of Kremlin personnel, airbrush out the faces of those who had been unceremoniously removed from office with regime change. Decades before the internet and Photoshop, you could still see faint images of parts of the peasant village, with what looked like homeless encampments on the bank of the river.
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    Default Re: Three Gorges Damn might fail

    Three views from Google Earth Pro as of this morning.







    Seems like they would have some fairly precise geolocations on the dam to check for movement. The data is probably not available to the public.
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    Default Re: Three Gorges Damn might fail

    OK, I know what is happening.

    Google Earth has a terrain simulator function, which uses topo maps to "bend" the satellite image to simulate mountains and slopes.

    Topo maps provided by many countries are notoriously coarse, inaccurate, and poorly georeferenced, and I would expect China to provide some pretty mean ones of a "strategic" location like the dam. Those images are being distorted by the software to simulate ondulations in the "terrain" that don't exist.

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    Default Re: Three Gorges Damn might fail

    ^This.

    Any number of the English Lake District waters have slopey-up edges.

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    Default Re: Three Gorges Damn might fail

    ^ Yeah, look at the center spillway seawall edges in the top view, straight, then massive distortion in the side view.

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    Default Re: Three Gorges Damn might fail

    The sky is falling?
    Simplicity is the ultimate sophistication. Leonardo da Vinci.

    If war is the answer........... it must be a profoundly stupid question.

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    If trump loses the election he will be like a balloon that after it's inflated is let go without tying the knot and it farts about the room bouncing off walls, ceiling and windows, in a fatally erratic implosion! Those near him will be blown away!

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    Default Re: Three Gorges Damn might fail

    My comment a few days ago about fear that the dam might collapse wasn't because of dodgy satellite images. It was because of something I read about Chinese officials being seriously concerned about the dam giving way, and the government trying to keep a lid on it. And now I can't find the site the story was on! JayInOz

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    Default Re: Three Gorges Damn might fail

    Quote Originally Posted by JayInOz View Post
    My comment a few days ago about fear that the dam might collapse wasn't because of dodgy satellite images. It was because of something I read about Chinese officials being seriously concerned about the dam giving way, and the government trying to keep a lid on it. And now I can't find the site the story was on! JayInOz
    One would think that any dam other than earthen would be designed for water loads right up to the top, at which point it's gonna spill over whether there is a spillway or not.
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    Default Re: Three Gorges Damn might fail

    The purpose of my post was not to cast doubt about the veracity of those reports, but simply to point out that distorted sat imagery can not be taken as proof of the dam's structural state.
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    Default Re: Three Gorges Damn might fail

    Well there is a bit of a flood downstream at the moment:
    Dam in China's Hangzhou opens all 9 floodgates for first time in history | Taiwan News

    TAIPEI (Taiwan News) — With torrential rain and massive flooding ravaging much of southern China, the Xin'anjiang Dam on Wednesday (July 8) opened all nine of its floodgates, causing 12 villages downstream to be inundated, impacting over 300,000 people.
    Simplicity is the ultimate sophistication. Leonardo da Vinci.

    If war is the answer........... it must be a profoundly stupid question.

    =-=-=-=-=-=-=-=-=-=-=
    If trump loses the election he will be like a balloon that after it's inflated is let go without tying the knot and it farts about the room bouncing off walls, ceiling and windows, in a fatally erratic implosion! Those near him will be blown away!

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    Default Re: Three Gorges Damn might fail

    ....and the Damn thing slowed down time!

    increasing the length of a day by 0.06 microseconds!
    Simplicity is the ultimate sophistication. Leonardo da Vinci.

    If war is the answer........... it must be a profoundly stupid question.

    =-=-=-=-=-=-=-=-=-=-=
    If trump loses the election he will be like a balloon that after it's inflated is let go without tying the knot and it farts about the room bouncing off walls, ceiling and windows, in a fatally erratic implosion! Those near him will be blown away!

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