Environmental Engineering Reference
In-Depth Information
The authors' view is that the overwhelming problem in too many cases is that those
doing the analysis have neither the proper understanding of the mechanics of the problem
and what are reasonable properties, nor a good, detailed understanding of the computer
programs. The result is an unfortunate waste of time and money.
The techniques are very valuable, done by competent persons, who understand dams,
material behaviour and numerical analysis.
11.8
PROBABILISTIC ANALYSIS OF THE STABILITY OF SLOPES
The use of probabilistic methods for assessing the stability of dam or other slopes, other
than mine pit slopes, is not common. This is despite a large body of research and publi-
cation into the topic, which have brought the state of the art to a relatively high degree of
sophistication.
Mostyn and Fell (1997) gives a thorough overview of the state of the art method. Other
reviews are given in Christian et al. (1992) and Wu et al. (1996).
Given the low incidence of slope instability failures of dams and the fact that many
accidents and failures can be attributed to weaknesses in the dam (e.g. by softening) or the
foundation (e.g. the presence of bedding surface shear in the rock), which would be
missed in probabilistic analysis just as they were in the deterministic, factor of safety
approach, the authors do not see a great need to use probabilistic analysis. The exception
could be for embankments built on soft clay foundations, where the method may help
demonstrate that a considerable degree of conservation in selection of the factor of safety
is required. See Duncan (2000) and Christian et al. (1992) for examples.
