The City of Fort Collins (Colorado) recently completed construction of a tunnel underneath BNSF Railway tracks to connect more than 30 miles of trails. The prospect of tunneling under an active rail line is a pretty big deal, and the railroad had strict requirements. The original concept of the tunnel was modified by the contractor and their engineer to utilize secant pile retaining walls to allow the construction of the portals closer to the rail line and decreasing the overall tunnel length. The tunnel was constructed by BT Construction and Lithos Engineering was their design engineer. Yenter construction was responsible for the retaining walls, including segments of sheet pile wall used to start things off. Anderson Drilling constructed the shafts for the secant pile wall and for the thrust wall. Read more about the project at TBM.
[Editor] National Science Foundation (NSF) Press Release – June 30, 2008. Screenshot Credits: Jeramy Decker, Kiewit Corp [/Editor]
Running for more than 1,000 kilometers along picturesque coastline, California’s Highway 1 is easy prey for many of the natural hazards plaguing the region, including landslides.
The California Department of Transportation (Caltrans) is currently building a kilometer-long tunnel to bypass one of the most landslide-prone stretches of the highway, the Devil’s Slide, to help ensure drivers’ safe passage.
Using a new software package developed by researchers at Virginia Tech in Blacksburg, Va., project engineers are getting a detailed 3-D view of the rock exposed in the excavation, adding a new tool for improving both safety and construction progress.
[Editor] Click through for the rest of the press release. [/Editor]
The Devil’s Slide Tunnel Project was originally scheduled to open at the end of 2012, but it has been delayed slightly to an early 2013 opening. If you look at some recent photos, you can hardly tell that there is anything left to finish. I’ve been following this project since it started, since to me it represents the essence of geoengineering, with important roles played by geotechnical engineers, geological engineers, hydrogeologists, and of course geotechnical contractors and tunneling specialists. I thought it would be interesting to list a few of the posts I’ve written about the project over the years and present a bit of information I only recently learned. Click through for more. [Image: kxyoung on Flickr]