PROPER RESTRAINT

摘要

Arecurring landslide along a stretch of Route 220 in Wyoming approximately 15 mi south of Casper that is referred to as the Narrows has been a maintenance and safety problem for the Wyoming Department of Transportation (WYDOT) since the mid-1960s. Shear movement as land slides down an embankment toward the North Platte River some 40 to 45 ft below the elevation of the roadway has endangered a 500 ft long stretch of the highway, which extends southwest of Casper along what was once the Oregon Trail. The highway section experienced vertical drops in pavement of up to 1 ft per year between 1966 and 2012, and by 2012 the continual patching meant that the total asphalt depth in some portions of the roadway near the slide exceeded 18 ft.