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Merged 8.8 quake in Sendai, Japan

I am very familiar with liquefaction because I live in Christchurch.
it is particularly nasty stuff. about 50% of the roads in Christchurch are damaged, and a lot have liquefaction. a hole appeared in the middle of one of the roads near where I live. it was about 2m across, round, and about 1m deep, and this was in an area not affected particularly badly by liquefaction.

I haven't been to see the eastern suburbs, but it is really bad over there.

also liquefaction amplifies the shaking, causing more damage, and is possibly why two relatively modern buildings fully collapsed, and several others are going to be demolished.

I have noticed that a lot of people seem to think that liquefaction is caused by burst mains. it is not, although it does look like it with the rate it shoots out sometimes.
the property on the corner of our street literally had a river of liquefaction coming out of it.
here is a good video showing the effects.

it is also really heavy, so it is nasty stuff to move, and when it dries, it literally gets EVERYWHERE! it is really light too, so even a light wind can start blowing it into the air.
 
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I saw a show on TV where they used a machine to shake the sand/soil mixture as they filled in the land, so that it wouldn't do that later.

Oh yeah, it was for those artificial islands they built in Dubai. It would make the mixture expel all the air and settle, so it wouldn't be a problem later.
 
BenBurch said:
My thought is that buildings in areas like that should be boats. That is they should be buoyant in a fluid that has the same density as the soil they sit on.
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Wouldn't that cause them to raise up out of the ground though? That doesn't sound like a good idea.
 
If the Japanese are going to rebuild in the tsunami zone, a building that would float isn't a bad idea. Put big pole in so it only goes up and down. Problem solved.

Well, except for the sewage.
 
Here's a story I just found on Bloomberg about this very subject:

Tokyo Bay Home Demand to Sag After Land Turned to Mud

Developers in Tokyo’s bayside neighborhoods, where apartments were built on reclaimed land, are halting sales after Japan’s earthquake turned some of the landfill into mud, shattered pipes and severed water supplies.

While most of Tokyo avoided major damage in the March 11 quake because of stringent building codes, in some parts of Tokyo Bay the magnitude-9 temblor triggered liquefaction, a phenomenon where soil loses its strength after violent shaking. The most affected suburb was Urayasu, one of only three residential areas in greater Tokyo where land prices rose last year, and the home of the Tokyo Disneyland resort.
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I'm telling you, they have this machine that shakes the soil as they put it in to keep that from happening. I'm surprised Japan doesn't force builders to do that.
 
r-j said:
I'm telling you, they have this machine that shakes the soil as they put it in to keep that from happening. I'm surprised Japan doesn't force builders to do that.
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I don't know but I would guess that they do in fact use that technique, but it may not be 100% effective. Dubai hasn't had an earthquake to test the actual effectiveness yet.
 
r-j said:
I'm telling you, they have this machine that shakes the soil as they put it in to keep that from happening. I'm surprised Japan doesn't force builders to do that.
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Well, it's possible that they do, now. I know liquefaction was a big problem in the Kobe quake, and I heard that they modified their building practices after that, but that wouldn't necessarily help land reclaimed before that.
 
commandlinegamer said:
Flexible piping exists.
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I don't know of any utility piping flexible enough to cope with a localized uplift of several ft. or more, especially when connected to or passing through a manhole structure.

I don't even know of any cabling which could handle that. Merely passing through a building expansion joint which is only designed for a couple of inches requires special efforts and fittings.

I'd be interested in finding out what other solutions are available.
 
They were concerned about quakes in Dubai, so they did all this shaking of the ground to cause the fill to settle, so that it wouldn't do so in an earthquake. (it seems they do get earthquakes there, rarely, but they do)

It was on a show about how they built the artificial islands. They were very concerned about the matter, even boring holes and checking after the fact to make sure it was all up to snuff.
 
I guess if a tsunami hits you wouldn't care if the flexible plumbing was sheared off. The important thing would be the house going up, floating, rather than washing out to see in a pile of rubble.
 
quadraginta said:
I don't know of any utility piping flexible enough to cope with a localized uplift of several ft. or more, especially when connected to or passing through a manhole structure.

I don't even know of any cabling which could handle that. Merely passing through a building expansion joint which is only designed for a couple of inches requires special efforts and fittings.

I'd be interested in finding out what other solutions are available.
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I believe that something similar has been proposed for use in the Netherlands.

Of course, this is for flooding and at a slow rate compared to a tsunami.
 
I don't think this short youtube video has been posted yet. It illustrates the effects of liquifaction in (to me) a highly disconcerting way, I mean where I come from the ground under my feet remains solid right??? All I can say is WOW.....




Compus
 
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