On Two Approaches to Slope Stability Reliability Assessments Using the Random Finite Element Method

The random finite element method has been increasingly used in the geotechnical community to investigate the influence of soil spatial variability and to bridge the gap between a traditional design and a reliability-based design. There are two approaches to calculate the reliability curves as a function of the traditional/global factor of safety in the literature. However, it is not clear how these two approaches may be related and why. This paper is devoted to answering this question, through the aid of an implemented auto-search algorithm within the strength reduction method and the quantification of the potential sliding volumes in the various possible Monte Carlo realisations of the soil spatial variability. The equivalences and differences between the two approaches, and thereby their respective merits and disadvantages, are explained and discussed for the most commonly used distribution types of soil strength properties, that is, normal and lognormal distribution. Computational efficiency has also been addressed in the form of pseudocodes, which can be readily implemented.