A simple first order uncertainity analysis is described which demonstrates how uncertainity in the factors which contribute to safety in an embankment influence the uncertainity of the factor of safety. Simular procedures can be applied to settlement, lateral movements or any other quantity that must be predicted before construction. A reliability index may be defined from the best estimate of the factor of safety and variance of the factor of safety. The reliability index is a measure of safety and is demonstrated by a figure which shows the number of standard deviations the expected value of the factor of safety is above a factor of safety of one. A decision on the factor of safety applicable to a project can be formulated from an uncertainity analysis using the reliability index. A minimum reliability index seems to be a better specification for safety than factor of safety alone. The influence of uncertainity on the factor of safety for a design based on a specified reliability is illustrated. The analysis is described of a case history of a highway embankment failure. Since construction and maintenance costs may be closely related to the factor of safety, the cost implications should be considered when a design factor of safety is chosen.

  • Supplemental Notes:
    • This paper is part of the proceedings of the Ohio River Valley Soils Seminar held in Lexington, Kentucky, October 5, 1973.
  • Corporate Authors:

    Kentucky Soil Mechanics and Foundations Group

    ASCE, Kentucky Section, 345 West 47th Street
    New York, NY  United States  10017
  • Authors:
    • Baker, W J
  • Publication Date: 1973-10-5

Media Info

  • Features: Figures; References; Tables;
  • Pagination: 10 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00262160
  • Record Type: Publication
  • Report/Paper Numbers: Proceeding
  • Files: TRIS
  • Created Date: Oct 22 1974 12:00AM