PROBABILITY OF SLIDING OF SOIL MASSES. ABRIDGMENT

Statistical analysis and probability theory can be used as alternatives to conventional (deterministic) methods for evaluation of slope stability. In this paper, the reliability of a soil slope against sliding was evaluated from its probability of failure. This was defined as the probability that the resisting moment M sub R was exceeded by the driving moment M sub S. Sliding was assumed to occur along a log-spiral path. This assumption is consistent with results obtained through stochastic modeling of the propagatin of failure surfaces. As the variation of the unit weight (gamma) of the soil is relatively small, gamma was assumed to be constant. Thus, moment M was expressed as a function of only two random variables: strength parameters c and t. The variability of c and t in the expression for the moment M was investigated by means of a Taylor series expansion. It should be noted that this method gives only approximate values for the mean and variance of M. If greater accuracy is required, a more precise procedure, possibly a simulation approach, should be employed. In the illustrative example it was found that the probability of failure of the slope was approximately 3.2 percent or, out of 100 identical slopes, on the average, 3.2 would fail. The reliability of this slope is then said to be equal to 36.8 percent. Based on the results of this study, it is concluded that the probabilistic model developed here can be used to find a value of the probability of failure (or, the reliability) of a soil slope (This depends on the slope geometry and on the statistical values of the soil parameters.) and the method can be applied to either deep or shallow failures (The kind of failure is reflected in the probability density functions of the coordinates of the center of the sliding surface). /Author/

Media Info

  • Media Type: Print
  • Features: Figures; References;
  • Pagination: pp 50-53
  • Monograph Title: Tolerable Movement of Bridge Foundations, Sand Drains, K-test, Slopes and Culverts
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00196580
  • Record Type: Publication
  • ISBN: 030902823X
  • Files: TRIS, TRB
  • Created Date: Aug 28 1979 12:00AM