SLOPE STEEPNESS FACTOR FOR PREDICTING EROSION ON HIGHWAY SLOPES

A number of field soil erosion tests were successfully accomplished on newly constructed highway fills at Putnamville and Evansville, Indiana, in 1985 and 1986. The slope steepnesses ranged from 9 to 50 percent. It is possible to use the Universal Soil Loss Equation (USLE), which is widely applied for prediction of soil erosion, for highway slopes. However, the empirical slope steepness factor (S) in the USLE has been developed for slopes of from 3 to 18 percent. Because most highway slopes exceed this range, it was necessary to generte original experimental data. The modified rainfall simulator needed to obtain the data and its use are briefly described. The S factor reflects the development of rills, and the impact of raindrops, and appears to reach a maximum value of 1.5 at an intermediate value of slope steepness of 20 percent (11.2 degrees). The S factor may change with slope length, soil properties, and elapsed time, and accordingly is not an independent factor. In this study, the ratios of total erosion (which consists of the erosion in dry, wet, and very wet runs) to the erosion due to very wet runs are close to a constant. The mean value is 6.348 with a coefficient of variation of 4.90 percent.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1988/1188/1188-007.pdf
• Record URL:
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• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1188, Effects of Geosynthetics on Soil Properties and of Environment on Pavement Systems. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Fan, Jen-Chen
  • Lovell, C W
• Publication Date: 1988

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 63-73
• Monograph Title: Effects of geosynthetics on soil properties and of environment on pavement systems
• Serial:
  • Transportation Research Record
  • Issue Number: 1188
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Data analysis; Erosion; Field tests; Fills; Highways; Mathematical analysis; Rain; Simulation; Slopes; Soils
• Old TRIS Terms: Slope steepness factor; Test results
• Subject Areas: Geotechnology; Highways; I42: Soil Mechanics;

Filing Info

• Accession Number: 00488605
• Record Type: Publication
• ISBN: 0309047579
• Files: TRIS, TRB, ATRI
• Created Date: Oct 31 1989 12:00AM