Rising Costs and Delays in Seattle Area Wastewater Plant and Tunnels

London’t mega-project known as Crossrail that involves the construction of 118 km (73 mi) of new rail line with 42 km (26 mi) of new tunnels. The geotechnical investigation for Crossrail included rock coring, and […]

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)

[…]

The Norwegian government wants to build a tunnel linking two fjords that would be large enough to pass 16,000 tonne cargo and passenger ships. The treacherous stretch of waterway has seen 46 accidents and 33 […]