Flood-Erosion Protection for Highway Fills

As a result of a series of investigations sponsored by the Highway Research Board of the Iowa State Highway Commission, a method was developed for constructing highway fills that would not be appreciably damaged by inundation even when subjected to high velocities of flow over the grade or along the side slopes. Preliminary investigations gl1ve considerable insight into the mechanism of failure of erosion protection and provided a rational basis for a design capable of being used for any required degree of resistance to scour. The recommended design embodies properly graded layers with the topmost layer bound in “rock sausages.” The size of the sausages required for various exposures was not determined, but full-scale tests showed that a minimum practicable size would be ample to protect highway fills under the most severe conditions likely to be encountered.