I've got the post-earthquake blues. I'm haunted by my own dream images of Haiti, and my current writing compulsion is dead. As well, I get the same number of ad clicks if I have 500 or 50 hits a day. And I've got a head cold!
So, I was excited about the Ottawa tunnel. My contention was that it could be constructed with intelligence, just like the Niagara Tunnel could have been constructed with intelligence. My 'Weenie' series would look at tunnels with the same horrible geology at Ottawa, but totally successful. My first look was the Seikan Tunnel, which isn't, successful, that is.
The Seikan Tunnel is currently the worlds longest tunnel, and may still win as the worst conditions in the world (until Ottawa comes along!). It was built through volcanic beds that were wrenched up to vertical, so it had lots of porous channels to the sea. And in Japan, you can't spit without hitting an active fault!
They constructed first a pilot tunnel, then a medium tunnel, and finally the main tunnel. Even with that (and an infinite amount of grout!), they still got pissed out of the tunnel once.
The tunnel can be considered an economic failure. They only made it wide enough to hold one standard train, and one dinky train. You can't go too fast because of air pressure. When you ride in it, you constantly hear the sea pouring in, to remind you that if there were to be an earthquake, you're dead! Needless to say, everybody takes the cheaper air flights!
So, this tunnel does not get on the candidate list. The new 'longest' tunnel will be the Goddard Base Tunnel, but that's TBM with excellent rock conditions. BAH!
2 comments:
I'm not so sure about the 'excellent rock conditions' of the Gotthard Base Tunnel. Trapped between the Aar and Gotthard Massifs is a sliver of Mesozoic sediments including some soft dolomites connected to the surface. I don't think I would have wanted to be anywhere near when they were drilling that section. "In some areas the rock was as soft as butter".
Neat.
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