Reliability Analysis of Slope based on Fellenius’s and Bishop’s Method

Abstract

This paper uses five reliability methods to analyze the stability of a slope. The stability of the slope is calculated by Fellenius’s method and Simplified Bishop’s method respectively. The main factors considered in slope stability are the cohesion and friction angle of soil. We assume that the cohesion and friction angle of soil are normally distributed, and their distribution is updated using the Bayesian method based on investigated field test data. We mainly studied the influence of the correlation coefficient between the cohesion and friction angle of soil and the slope angle on the stability of the slope. The results showed that methods of IRSM or AFORM are more accurate in reliability analysis of the slope, while MCS’s results fluctuate greatly for sample points and are not sufficient due to the limitation of calculation time.  The probability of failure increases as the value of the correlation coefficient between cohesion and friction angle increases. Results calculated by Fellenius’s method are more conservative, and Simplified Bishop’s method is recommended for steep slopes.