3 Gorges Dam potential failure

In summary, the Three Gorges Dam in China is a gravity dam that is held in place by the weight of the concrete and does not require piles driven into bedrock. The structures are connected together with rebar and expansion joints to accommodate changing temperatures. The dam sits on two major fault lines and is tied together with rebar to prevent lateral movement. The interior of the dam is filled with low grade concrete for compressive resistance while the exterior is made of higher strength concrete. Repairing the dam would require draining the lake and digging through meters of material, making it a lengthy process.
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Ranger Mike
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not sure Mech Eng is proper forum for this. The 3 Gorges dam in China has very high flooding up river and more rains coming. Will the lack of piling driven to bedrock matter?
The dam is a series of massive re-bar and concrete wide base tapering to narrower top. Does anyone know if these structures are " tied" togeather via connecting rebar sections? I researched and apparently no piles were drive into bedrock so only the shear weight is anchoring the massive structures. My thinking is the whole dam is tied togeather making one huge concrete chain acros the river and should be impossibel to fail if materials are to standard. Is this correct or fuzzy thinking?
 
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Someone had posted online sat photos showing the dam has bowed:

https://www.reuters.com/article/us-...re Three Gorges,landslide risks in the region.

However, China said it was the photo imaging that had the problem not the dam.

https://www.britannica.com/topic/Th...Gorges Dam, dam on,dam structure in the world.

More recently, a Chinese Hydrologist has questioned the Dam's safety:

https://www.taiwannews.com.tw/en/news/3951673

https://7news.com.au/news/disaster-...flooding-threatens-three-gorges-dam-c-1119460
 
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yes i saw the photos and looks like pixelation problem stiching photos togeather..concrete can not bow that much i think.
 
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https://www.publications.usace.army.mil/Portals/76/Publications/EngineerManuals/EM_1110-2-2200.pdf

Ranger Mike said:
Summary:: not sure Mech Eng is proper forum for this. The 3 Gorges dam in China has very high flooding up river and more rains coming. Will the lack of piling driven to bedrock matter?

Does anyone know if these structures are " tied" togeather via connecting rebar sections? I researched and apparently no piles were drive into bedrock so only the shear weight is anchoring the massive structures
Gravity dam = the weight of the concrete holds the dam in place, which in turn holds back the water.
Piles - not needed to hold the weight of the dam, as the dam would be constructed right on top of the bedrock formation.
Structures connected together = not sure what you mean, what structures?

Since the dam can be several meters wide ( or long, definition wise ) - the 3 gorge is over 2000 meters, some sort of expansion joints would have to in place, every several meters, to accommodate the changing temperatures over the year. Each section should be designed to be structurally stable. One whole solid piece of concrete ...?
 
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Ifin you got all that water building up behind you, one would think you would want to put a stake in the ground to anchor your dam. Drill intor bedrock and tie in the dam so lateral movement isnot going to happen. Especially since you decided to buildon unstable ground to begin with . Three Gorges Dam sits on two major fault lines -- Jiuwanxi and Zigui-Badong. i would have connected each concrete poured portion to the other with re-bar for tension and tied the whole thing togeather... now did this happen?
tell me this is not needed and i am full of beans?? does concrete flex and distort? we are only talkingh about 40% of chinas GDP going out when it brakes..
 
  • #6
Ranger Mike said:
does concrete flex and distort
It doesn't do well in tension.
Gravity keeps it in compression.

Another failure mode would be tipping.
The hydro static pressure underneath the structure has to be controlled so as to not make the upstream part begin to uplift, or the whole structure begin to attempt to float. Drainage, or no drainage condition, would have to be taken into account. Again, a suitable mass of concrete helps in this regard.
 
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Ranger Mike said:
tell me this is not needed
Not needed for a gravity dam.

The interior of the dam is just filler - say a low grade 10 to 1 mixture, to add compressive resistance and the weight.
The exterior is of higher strength concrete.

Concrete keys are what hold the sections from moving relative to one another, not metal that could corrode, expand and destroy the integrity of the structure. And how would anyone test for that. One would have to add interior walkways and inspection points.
To repair one would then have to drain the "lake" and dig through meters of material.
Out of service for years and years.

It's not like a road that can be ripped up and replaced in suitable time frame.
These things are massive.
 
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excellent info. this is why this forum is so valued! Thank you!
 

1. What is the 3 Gorges Dam and why is there concern about its potential failure?

The 3 Gorges Dam is a hydroelectric dam located on the Yangtze River in China. It was built to generate electricity, control flooding, and improve navigation. However, there have been concerns about its potential failure due to its location in a seismically active area and the immense pressure it puts on the surrounding land.

2. What are the potential consequences of the 3 Gorges Dam failing?

If the 3 Gorges Dam were to fail, it could result in catastrophic flooding downstream, displacement of millions of people, and disruption of water and electricity supplies. It could also lead to environmental damage and loss of valuable agricultural land.

3. How likely is the 3 Gorges Dam to fail?

The likelihood of the 3 Gorges Dam failing is a topic of debate among experts. Some argue that the dam was built with strong engineering and safety measures, making the chances of failure low. However, others point to the dam's location in a seismically active area and concerns about its design and construction, leading to a higher risk of failure.

4. What measures have been taken to prevent the potential failure of the 3 Gorges Dam?

To mitigate the potential failure of the 3 Gorges Dam, various measures have been taken, including regular inspections and maintenance, reinforcing the dam with additional concrete, and implementing an emergency response plan in case of failure. Additionally, there have been proposals to lower the water level in the reservoir to reduce pressure on the dam.

5. What are the ongoing efforts to address the concerns about the 3 Gorges Dam potential failure?

There are ongoing efforts to address the concerns about the 3 Gorges Dam potential failure, including conducting further studies and research, implementing additional safety measures, and considering the decommissioning of the dam in the future. The Chinese government has also allocated funds for disaster prevention and emergency response in case of a dam failure.

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