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Big Trouble in Little China

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  • #16
    Re: Big Trouble in Little China

    Originally posted by touchring View Post
    ... The controversy was the dam opened the flood gates in late June even when the water levels were much lower than a couple years before, leading to speculation that the dam was structurally weaker than it was previously...
    That is indeed pretty strong evidence the dam has serious problems. This dam is a major hydro power plant. Lowering the water level (the hydraulic "head" for the turbines) dramatically reduces power output. Head level for the turbines is fundamental to the design of the whole gigantic system. The authorities would not lower it without a lot of meetings and some pretty serious concerns.

    Those concerns might not be about the dam collapsing. It might be problems with the turbine runners, or wicket gates, or penstock, or tailrace... Some of the power machinery may be faulty and need reduced stress.

    I spent all of 5 minutes googling around this and didn't find any formal warnings from engineering societies or government bodies, but then this is China. Most of the chatter seems to be exactly as Mike originally posted, those before and after Google Earth photos. China says the photos are doctored and false. Here's what Google maps shows now

    https://www.google.com/maps/search/t.../data=!3m1!1e3

    This looks dramatically better than the photos in Mike's original post. I'll assume the direct google map image at the link here is a truthful image, the after image in the article is false, and the dam has not moved much.

    But if they've lowered the pool level and kept it down, something is seriously wrong somewhere.

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    • #17
      Re: Big Trouble in Little China

      In 2009 a Russian hydro dam had a catastrophic failure of the power machinery. The dam structure as a whole stayed intact and held back the river. The power plant is just finishing repairs now, a decade later.

      Here's some photos






      If you haven't spent time in big hydro dams you might not appreciate the enormous scale of this structure.
      In the rubble on the right, look at those yellow cranes. Those are big hundred ton cranes.
      In the "before" picture, notice the circles on the floor. Those are the top covers for the round generators; the water turbines are a few stories below, down in the water.

      Here's a shot of a generator rotor after the event. It's one of the circles on the floor. Notice the people standing on the rotor to get a sense of scale.
      There is not much empty space or air in such a rotor. You can think of it as a solid chunk of copper and steel.
      Hidden under it is the main drive shaft going down to the turbine. It's a solid steel shaft about 3 feet in diameter and maybe 30 feet long. Close under this rotor is a shaft coupling to disconnect it. The coupling is pretty close to the generator rotor, so the rotor stub shaft to the coupler might be eight or ten feet long.



      Hydro generators turn at low speeds, this one turns at about 140 RPM. I would expect this rotor to weigh about 250 tons; that's 40 fully loaded semi trucks.

      A rotor like this was the problem. I don't think it was this particular rotor because it looks like this one's still inside the ruins of it's stator.
      But one of these broke free at speed. It bashed through the structure around it, and went dancing across the generator deck on it's stub shaft like some gigantic child's spinning top. As it danced everything it bumped into or moved over disintegrated.

      The operators had foolishly pushed the failed generator to it's absolute maximum one too many times and all hell broke loose.

      This is one possible reason China might be reducing stress on it's power machinery at three gorges dam. To avoid something like this.
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      Last edited by thriftyandboringinohio; 07-25-20, 01:54 PM.

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      • #18
        Re: Big Trouble in Little China

        Originally posted by thriftyandboringinohio View Post
        https://www.google.com/maps/search/t.../data=!3m1!1e3

        This looks dramatically better than the photos in Mike's original post. I'll assume the direct google map image at the link here is a truthful image, the after image in the article is false, and the dam has not moved much.
        There's a lot of fake satellite photos showing the dam highly distorted which I read is impossible because concrete would have disintegrated if they could be seen distorted that way visually. I don't believe the dam would collapse just because of one flood, but if this flood repeats every year and along with some future seismic event, the lifespan of the dam could be reduced to maybe only decades instead of 100 years originally planned.

        Read this from the state media. This was 30 June before the flood became really serious in mid-July.

        . The move aimed at reducing the reservoir's water level from 147.51 meters days ago down to a safe level of 145 meters, following days of heavy rain.
        Last edited by touchring; 07-25-20, 02:10 PM.

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        • #19
          Re: Big Trouble in Little China

          Originally posted by thriftyandboringinohio View Post
          In 2009 a Russian hydro dam had a catastrophic failure of the power machinery. The dam structure as a whole stayed intact and held back the river. The power plant is just finishing repairs now, a decade later.

          Here's some photos






          If you haven't spent time in big hydro dams you might not appreciate the enormous scale of this structure.
          In the rubble on the right, look at those yellow cranes. Those are big hundred ton cranes.
          In the "before" picture, notice the circles on the floor. Those are the top covers for the round generators; the water turbines are a few stories below, down in the water.

          Here's a shot of a generator rotor after the event. It's one of the circles on the floor. Notice the people standing on the rotor to get a sense of scale.
          There is not much empty space or air in such a rotor. You can think of it as a solid chunk of copper and steel.
          Hidden under it is the main drive shaft going down to the turbine. It's a solid steel shaft about 3 feet in diameter and maybe 30 feet long. Close under this rotor is a shaft coupling to disconnect it. The coupling is pretty close to the generator rotor, so the rotor stub shaft to the coupler might be eight or ten feet long.



          Hydro generators turn at low speeds, this one turns at about 140 RPM. I would expect this rotor to weigh about 250 tons; that's 40 fully loaded semi trucks.

          A rotor like this was the problem. I don't think it was this particular rotor because it looks like this one's still inside the ruins of it's stator.
          But one of these broke free at speed. It bashed through the structure around it, and went dancing across the generator deck on it's stub shaft like some gigantic child's spinning top. As it danced everything it bumped into or moved over disintegrated.

          The operators had foolishly pushed the failed generator to it's absolute maximum one too many times and all hell broke loose.

          This is one possible reason China might be reducing stress on it's power machinery at three gorges dam. To avoid something like this.
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          Great post.

          I’ve been in a few hydro dams, very impressive examples of civil engineering.

          Hydro dams are increasingly in the headlines in recent years, due to their under appreciated importance.

          Iraq’s Haditha Dam seizure from Saddam Hussein’s forces to prevent its demolition and flooding...and eventual recommissioning.

          Ukraine’s Dnieper Dam kinetic cyber attack by Russia in 2015-2017

          Afghanistan’s Kajaki Dam 10 year battle against the Taliban to deliver a turbine and commission the dam to connect it to the national power grid

          Ethiopia’s Grand Ethiopia Renaissance Dam that is majority complete and currently having its reservoir filled violently opposed by Egypt(with military units specifically trained to seize upriver infrastructure recently trained by US/UK forces)

          Much as we under appreciate the importance of protecting against pandemic, the same can be said with national infrastructure of international importance.

          Comment


          • #20
            Re: Big Trouble in Little China

            Originally posted by touchring View Post
            There's a lot of fake satellite photos showing the dam highly distorted which I read is impossible because concrete would have disintegrated if they could be seen distorted that way visually. I don't believe the dam would collapse just because of one flood, but if this flood repeats every year and along with some future seismic event, the lifespan of the dam could be reduced to maybe only decades instead of 100 years originally planned.

            Read this from the state media. This was 30 June before the flood became really serious in mid-July.
            Those “after” photos are ridiculous.

            I wonder if a better comparison than ‘before/after’ photos might be with Fukushima’s nuclear plant, where everything was fine until it wasn’t

            In short, my concern is around non-linear communication of escalating bad news, which is a real risk due to both long-standing cultural and more recent communist cult of infallibility reasons.

            Comment


            • #21
              Re: Big Trouble in Little China

              Originally posted by lakedaemonian View Post
              Those “after” photos are ridiculous.

              I wonder if a better comparison than ‘before/after’ photos might be with Fukushima’s nuclear plant, where everything was fine until it wasn’t

              In short, my concern is around non-linear communication of escalating bad news, which is a real risk due to both long-standing cultural and more recent communist cult of infallibility reasons.
              Personally, if I have no information or the source is unreliable, I always assume the worst case scenario.
              Last edited by touchring; 07-26-20, 12:09 AM.

              Comment


              • #22
                Re: Big Trouble in Little China

                Originally posted by touchring View Post
                Personally, if I have no information or the source is unreliable, I always assume the worst case scenario.
                At the end of the day, we can always rely upon the professionalism of NASA. https://earthobservatory.nasa.gov/im...s-spill-water? There is no sign of anything wrong with the Three Gorges dam.

                Comment


                • #23
                  Re: Big Trouble in Little China

                  Originally posted by Chris Coles View Post
                  At the end of the day, we can always rely upon the professionalism of NASA. https://earthobservatory.nasa.gov/im...s-spill-water? There is no sign of anything wrong with the Three Gorges dam.
                  And then this turned up. https://youtu.be/5O1w2UelZZQ

                  Comment


                  • #24
                    Re: Big Trouble in Little China

                    Originally posted by Chris Coles View Post
                    And then this turned up. https://youtu.be/5O1w2UelZZQ

                    Great find Chris, thanks.

                    When historic flooding occurs, it gets pretty tricky to manage dams and levees.
                    Operators are forced into a retreating action, picking which areas to sacrifice and which areas to defend until the last.
                    If it rains long enough everything floods.

                    Once reservoirs are full the dams need to be opened to let floodwaters flow through just to preserve the dams.
                    So as the video said, they stop functioning as flood control.
                    Destroying levees is another way to surrender one area to flooding hoping to preserve another.

                    I recall flying over the Mississippi river a quite a few times in 1993 when it suffered huge floods.
                    The river was miles and miles wide in places with just the odd treetop or barn roof sticking out of the water.

                    Comment


                    • #25
                      Re: Big Trouble in Little China

                      VERY Little is being said on the MSM............mind you the CCP own most of it, except the Marxist BBC!

                      Comment


                      • #26
                        Re: Big Trouble in Little China

                        China will have to import a LOT of FOOD, Rice & others........demand drives prices.
                        On a side note I had my hair cut today & Ian my stylist tells me his wife works in the Casino in Liverpool.
                        Its been cracked down because it was used for Drug money.......however they have new clients......Chinese students!

                        One lad studing at Liverpool Uni likes to loses around £11,000 on a Saturday night!

                        Comment


                        • #27
                          Re: Big Trouble in Little China

                          Originally posted by Mega View Post
                          China will have to import a LOT of FOOD, Rice & others........demand drives prices.
                          On a side note I had my hair cut today & Ian my stylist tells me his wife works in the Casino in Liverpool.
                          Its been cracked down because it was used for Drug money.......however they have new clients......Chinese students!

                          One lad studing at Liverpool Uni likes to loses around £11,000 on a Saturday night!
                          He is no doubt funding the operation.

                          Comment


                          • #28
                            Re: Big Trouble in Little China

                            Yes, but suddenly he (& the rest of them) are not there..........

                            Comment


                            • #29
                              Re: Big Trouble in Little China

                              Originally posted by Mega View Post
                              Yes, but suddenly he (& the rest of them) are not there..........
                              In which case, "& the rest of them", were cover and his job is finished.

                              Comment


                              • #30
                                Re: Big Trouble in Little China

                                This is a good analysis of the devastation that would ensue and second-order effects if the dam breaks:
                                EDIT: this is a better link: https://twitter.com/man_integrated/s...36336012038145

                                The Yangtze River Economic Basin has a GDP of more than $6.5 trillion, or about half of all China's GDP. Recall, China represents 28% of all manufacturing output - globally. More than half of that is in the YREB. 15% of the world's production would go offline in 24 hours.
                                ...

                                Most companies do not have the cash reserves or lending flexibility to sustain a year of no revenue while they change sourcing/factories.

                                They'll simply fold.

                                Last edited by shiny!; 08-01-20, 06:55 PM.

                                Be kinder than necessary because everyone you meet is fighting some kind of battle.

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