Monday, August 10, 2009
Niagara tunnel goes for immediate casting
That's the giant floor caster moving down the tunnel. It can be seen that the rest of the tunnel has been finished by shotcrete. So, they are just going to follow the overbreak, and let the tunnel vary in cross-section. Perhaps this doesn't do too much to water flow, not as much as all the corner-cutting they're doing.
It's very interesting in that they are going against decades of developed practice with the rock squeeze in this area. However, the contractor will be all cleaned up and gone before any trouble shows up. I'm not really going to harp on it any more, since this will only show up in 10 years.