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.
I was reading the ASCE News, January edition which announced the 5 finalists for the 2010 Outstanding Civil Engineering Achievement (OCEA) Award and I was struck by the significant geotechnical engineering and geoengineering components of these projects. Read on as I highlight some of things hidden beneath the ground of these remarkable projects. […]