A nifty BIM-type view of the proposed bored tunnel for Washington SR 99, the tunnel to replace the aging Alaskan Way Viaduct along Seattle’s waterfront. It’s pretty neat to see the piles and foundations for other structures and major utilities as the bore passes by them. A little on the longer size, at around 5 minutes.
Project Related
Crossrail – the engineering geology
For those outside the UK, the Crossrail project is a mega-project upgrade to the London metro area’s subway system. The tunneling portion of the project will consist of 21-km of twin-bore tunnels excavated by eight […]
Project Related
Geothermal Rig Drills Into Subway Tunnel in Stockholm, Sweden
And a train was actually hit! Fortunately it was stationary on the tracks, but it crushed the side panel of the driver’s carriage. Neither the driver nor any passengers were injured in the incident. The […]
Failures
Cologne Tunnel Collapse: Investigations Focus on Tiebacks and Groundwater
The latest information to come out of the collapse of a subway tunnel excavation in Cologne, Germany is that investigators are evaluating the ground anchors or tiebacks that were holding open the subway tunnel excavation. There doesn’t appear to be much information available to the public yet, and the New Civil Engineer article mostly quoted academics saying an anchor failure “could” have caused the collapse. Apparently at the time of the collapse, the excavation had reached the bottom depth after the slurry walls had been constructed along with the ground anchor system. Crews were supposedly working on the base slab which would have undoubtedly stiffened up the whole system. For what its worth, an anonymous comment left at the bottom of that article indicated that after half of the debris had been excavated, the diaphragm walls were still intact and without apparent displacement. So what other theories have been floated? Read on for more info. (Image Credit: New Civil Engineer)