Effective control of erosion on highway slopes involves assessing the erosive environment correctly, predicting the erosion resistance of materials before their placement or exposure on the slopes, and using slope maintenance and traffic control in order to minimise slope erosion-resistance damage. A laboratory testing process was developed that simulates the typical slope erosion environment. The relative importance of precipitation and flow over the slopes was explored. The relationship between precipitation and overland flow to slope erosion is such that both must be considered or erosion resistance will be overestimated. The erosion resistance of soil and prospective slope protection systems are evaluated and compared with field erosion damage. Excellent agreement between the predicted slope response and field observations was found. Crushed rock, resistant to weathering, was found to function effectively when placed on slopes as steep as 2:1. Angular particles, larger than 0.187 In., Were stable on slopes for the 50-yr, 30-min event when the concentration of these particles was greater than 20 percent. Erosion resistance was found to increase as the ratio of longest particle axis length to the shortest particle axis length increases. The phenomena of natural slope armoring was examined and guidelines were developed for recognising soil armoring.
Samenvatting