Probabilistic slope stability analysis using limit equilibrium, finite element and random finite element methods

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2015

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Akbaş, Burak

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In recent years, geotechnical engineers are moving more towards decision-making processes based on reliability assessment, since accounting for soil variability and carrying out probabilistic analyses result in significant savings in designs, and possible prediction of failure events. Objectives of this study are to investigate and compare different methodologies for probabilistic slope stability analyses as well as with deterministic methodologies, in terms of factor of safety, the probability of failure, and the critical failure surface. For this purpose probabilistic limit equilibrium tools (Slide and Slope/W) and probabilistic finite element tools (Phase 2 and PLAXIS2D) are utilized. Furthermore spatial variability of shear strength of soils is considered by Rslope2D software and newly-developed PLAXIS2D-Python scripting in this study. The effect of coefficient of variation and spatial correlation length is also studied. The most significant findings of this study are: (1) a deterministic FS value greater than 1.00 does not always mean that the slope is “safe” in traditional-sense, examples are shown where factor of safety of 1.50 can have a probability of failure of 30%. (2) As the coefficient of variation (COV) value increases, the probability of failure (PF) increases. (3) The results of probabilistic slope stability analyses are significantly influenced by the spatial correlation length. The results of this study are believed to be useful for further understanding of the probabilistic slope stability concept and the effects of soil heterogeneity on slope stability evaluations with the aim of better geotechnical risk management and communication.

Subject Keywords

Slopes (Soil mechanics), Finite element method., Soil stabilization., Equilibrium.

URI

http://etd.lib.metu.edu.tr/upload/12619091/index.pdf
https://hdl.handle.net/11511/24970

Collections

Graduate School of Natural and Applied Sciences, Thesis

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Citation Formats

B. Akbaş, “Probabilistic slope stability analysis using limit equilibrium, finite element and random finite element methods,” M.S. - Master of Science, Middle East Technical University, 2015.