Safety and safety factor in geotechniqui

Abstract

Attention is called to the great diversity of values of the safety factor used in Geotechnique, it being emphasized that such a diversity does not necessarily imply differences in safety, i.e. different probabilities of failure, for the corresponding works. The influence of the magnitude of the shearing-failure surface over the value of the safety factor is then considered and, by means of an example, it is shown that as that magnitude increases the safety factor corresponding to a given safety decreases. Finally in a study of brittle soils, which present a peak strength, it is shown that higher safety factors have to be adopted for taking that strength into account in the stability computations, the conclusion then being that peak strength need not be considered unless it markedly exceeds residual strength.