|Jun16-11, 04:00 AM||#1|
The geological issues of the Fukushima Daiichi
Just because there is a thick bottom concrete doesn't make it a floating box. If it's a floating box design then all of the bottom concrete is a supporting structure. To build it like this is expensive.
If it's not a floating box then there are weaker parts and stronger parts in the bottom concrete.
Another interesting thing is do they have a base isolation system or some other seismic vibration control system.
I guess the simplest/cheapest design would be this: there are footings that support the weight of the building and then there are beams to transfer weight from one footing to another if there happened to be a landslide underneath one footing.
These are interesting things to study on their own.
The first thing is a crack which is directly created by a fault line. I have an impression that these cracks rarely cut through hard rocks in Fukushima area although now this has happened:
How much this has happened in the Fukushima area is again an interesting thing itself.
At one point there was a news report where TEPCO said it cannot deny the possibility that in the number #3 reactor some major damage could have been done by the earthquake itself (I think it was a piping system).
It will take many years until they will finally conclude did the earthquake itself cause any major problem. And who is going to study it? TEPCO itself or some independent research team? (I hope the latter and I hope also not just an IAEA team.)
If at the end they would conclude that the earthquake itself actually did cause some major damage they would also start to find reasons behind it.
One thing is of course that ground acceleration numbers were above design parameters. But at this point they could also question if the whole plant has been built in a proper place / in a proper manner (soil amplification & foundation type etc).
The soil amplification studying as a branch of science is quite young, AFAIK, at least when it concerns the actual maps over different areas. Perhaps the theories are older. For instance: do they have soil amplification maps all over Japan? When I studied a little bit soil amplification maps from the U.S. I noticed some of them were made only quite recently. Like this one was presented in 2002, perhaps made a couple of years earlier:
So even if we don't know how is it going to proceed it is still an interesting thing to study. How well are the soil amplification aspects understood all over the world? What kind of foundation types are they using when they are not building on a top of granite/other hard rock? Should a proper soil amplification study be required in the future when building in seismic areas? How about existing NPP:s, should we force them to make soil amplification studies if none exists for that area?
These are interesting questions and I think one can study it a little further without speculating. Like: What kind of foundation type do they really have in Fukushima? Do they have soil amplification maps all over Japan?
|Jun16-11, 05:14 AM||#2|
Discussion about the definition of 'bedrock' from another thread:
This discussion could perhaps be directed here as it contains same issues that has also been discussed in the main thread.
One thing to note:
Edit: Could somebody (native-English) propose better tags?
Now I have: # foundation # geology # groundwater # rock # soil
|Jun16-11, 07:56 AM||#3|
I came across the following in an article in the German daily "Die Welt" published on March 15 about whether or not contamination of the water table was likely, which talks about the local type of rock:
English translation by me:
It also mentions that the base of the foundations is a 4 metre thick slab of reinforced concrete.
You can use Google translate or Google Chrome to read a rough translation of the complete article into the language of your choice.
|Jun16-11, 11:20 AM||#4|
The geological issues of the Fukushima Daiichi
Recently there has been a couple of great posts concerning groundwater contamination / geological structure of the Fukushima plant. I am linking them here so that they can be easily found later:
First one was by tonio who says he is a geologist, specialized in soil and groundwater contamination:
The second one was by Azby who was able to get some information from a Japanese specialist, a professor of geology:
My question for tonio: In one paper TEPCO said they are going to empty the contaminated sub-drain pits of the unit #1 - #4 at some point. How is it controlled that these sub-drain pits won't overflow? Is there some kind of automatic measurement of the water level in the sub-drain pits or are they controlled manually?
I have not noticed TEPCO saying that they have emptied the unit #1 - #4 pits. For units #5 - #6 they did it a long time ago. There might be more groundwater near #5 - #6 than #1 - #4.
|Apr18-12, 02:16 AM||#5|
What is the best university to study geology in Australia? I have applied for a BAs(geology) at UWA and don't know whether I have chosen the right uni. Are there any better ones to go to? Also, what are the chances of getting a job after completing the BAs in geology in the resource sector for Australia, I thought it looks good so thats why I'm changing my career. I'm 27 now and thought I still have time :) let me know your thoughts. Thanks!
|foundation, geology, groundwater, rock, soil|
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