The large-radius vertical and horizontal curves necessary for high speed ground transportation require cuts and fills that modify the natural topography so much that many new drainage channels are required. The capacity of natural channels may be overtaxed by quick runoff from impervious paved areas. Methods of protecting channels against erosion are described and the deficiencies of current practices are explained. Experimental and field evidence is presented showing the necessity of using Terzaghi's inverted filter to minimize loss of soil by leaching. Terzaghi conceived the idea of preventing this type of failure by covering the danger zone with a filter layer incorporating material many times as pervious as the soil that might be washed away, but with interstices small enough to keep the soil particles from penetrating it. He formulated criteria for the necessary grain size relationships and patented and successfully used the system in Austria 50 years ago. It has since been universally accepted among dam designers. Experience and research indicate that only slight modifications of his original quantitative relationships are necessary for channels.

  • Corporate Authors:

    Planning Transport Associates, Incorporated

    P.O. Box 4824, Duke Station
    Durham, NC  United States  27706
  • Authors:
    • Posey, C J
  • Publication Date: 1974

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00095258
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Jul 15 1975 12:00AM