Practical reliability analysis of slope stability by advanced Monte Carlo simulations in a spreadsheet

2011 ◽  
Vol 48 (1) ◽  
pp. 162-172 ◽  
Author(s):  
Yu Wang ◽  
Zijun Cao ◽  
Siu-Kui Au
Keyword(s):  
Monte Carlo ◽  
Slope Stability ◽  
Spatial Variability ◽  
Soil Properties ◽  
Reliability Analysis ◽  
Slip Surface ◽  
Probability Of Failure ◽  
Critical Slip Surface ◽  
Microsoft Excel ◽  
Mcs Method

This paper develops a Monte Carlo simulation (MCS)-based reliability analysis approach for slope stability problems and utilizes an advanced MCS method called “subset simulation” for improving efficiency and resolution of the MCS at relatively small probability levels. Reliability analysis is operationally decoupled from deterministic slope stability analysis and implemented using a commonly available spreadsheet software, Microsoft Excel. The reliability analysis spreadsheet package is validated through comparison with other reliability analysis methods and commercial software. The spreadsheet package is then used to explore the effect of spatial variability of the soil properties and critical slip surface. It is found that, when spatial variability of soil properties is ignored by assuming perfect correlation, the variance of the factor of safety (FS) is overestimated, which may result in either over (conservative) or under (unconservative) estimation of the probability of failure (Pf = P(FS < 1)). When the spatial variability of soil properties is considered, the critical slip surface varies spatially and such spatial variability should be properly accounted for. Otherwise, the probability of failure can be significantly underestimated and unconservative.

An efficient search method for finding the critical circular slip surface using the Monte Carlo technique

2001 ◽  
Vol 38 (5) ◽  
pp. 1081-1089 ◽  
Author(s):  
AI Husein Malkawi ◽  
W F Hassan ◽  
S K Sarma
Keyword(s):  
Monte Carlo ◽  
Stability Analysis ◽  
Slope Stability ◽  
Factor Of Safety ◽  
Global Minimum ◽  
Reliable Method ◽  
Slip Surface ◽  
Search Method ◽  
Monte Carlo Technique ◽  
Critical Slip Surface

Locating the critical slip surface and the associated minimum factor of safety are two complementary parts in a slope stability analysis. A large number of computer programs exist to solve slope stability problems. Most of these programs, however, have used inefficient and unreliable search procedures to locate the global minimum factor of safety. This paper presents an efficient and reliable method to determine the global minimum factor of safety coupled with a modified version of the Monte Carlo technique. Examples are presented to illustrate the reliability of the proposed method.Key words: factor of safety, method of search, critical slip surface, circular, global, Monte Carlo.

Analysis of Earth-Rockfill Dam Slope Stability by Strength Reduction Method Based on Nonlinear Strength

2011 ◽  
Vol 243-249 ◽  
pp. 2271-2275
Author(s):  
Shu Yu ◽  
Li Hong Chen ◽  
Ze Ping Xu ◽  
Ning Chen
Keyword(s):  
Shear Strength ◽  
Slope Stability ◽  
Reduction Method ◽  
Slip Surface ◽  
Strength Reduction ◽  
Strength Parameter ◽  
Strength Reduction Method ◽  
Critical Slip Surface ◽  
Rockfill Dam ◽  
The Earth

In the design process of the earth-rock dam, the slope stability problem was always focused on. The shear strength of rockfill in the earth-rock dam had strong nonlinear characteristics. The characteristic directly affected the factor of safety (FOS) of stability of dam slope and the determination of the critical slip surface. The shear strength parameter of rockfill was related to the minimum principal stress σ3 closely. And the value of σ3 had close relationship with the deformation characteristics of filling material and the process of dam filling etc. Strength reduction method has been widely used in solving the FOS of slope stability, and this method has the advantage on the searching of the critical slip surface. Combining the deformation and stress analysis of earth-rockfill dam filling process and the strength reduction method, this paper proposes a comprehensive method of dam slope stability analysis.

A Comparative Study on Locating Critical Slip Surface in 2D and 3D Limit Equilibrium Stability Analysis of Slopes

2012 ◽  
Vol 446-449 ◽  
pp. 1905-1913
Author(s):  
Mo Wen Xie ◽  
Zeng Fu Wang ◽  
Xiang Yu Liu ◽  
Ning Jia
Keyword(s):  
Stability Analysis ◽  
Slope Stability ◽  
Safety Factor ◽  
Slip Surface ◽  
Limit Equilibrium ◽  
Three Dimensional ◽  
Slope Stability Analysis ◽  
Equilibrium Stability ◽  
Critical Slip Surface ◽  
Minimum Safety Factor

The Various methods of optimization or random search have been developed for locating the critical slip surface of a slope and the related minimum safety factor in the limit equilibrium stability analysis of slope. But all these methods are based on a two-dimensional (2D) method and no one had been adapted for a search of the three-dimensional (3D) critical slip surface. In this paper, a new Monte Carlo random simulating method has been proposed to identify the 3D critical slip surface, in which assuming the initial slip to be the lower part of an ellipsoid, the 3D critical slip surface in the 3D slope stability analysis is located by minimizing the 3D safety factor of limit equilibrium approach. Based on the column-based three-dimensional limit equilibrium slope stability analysis models, new Geographic Information Systems (GIS) grid-based 3D deterministic limit equilibrium models are developed to calculate the 3D safety factors. Several practical examples, of obtained minimum safety factor and its critical slip surface by a 2D optimization or random technique, are extended to 3D slope problems to locate the 3D critical slip surface and to compare with the 2D results. The results shows that, comparing with the 2D results, the resulting 3D critical slip surface has no apparent difference only from a cross section, but the associated 3D safety factor is definitely higher.

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