Study of Slope Stability Using the Bishop Slice Method: An Approach Combining Analytical and Numerical Analyses

Abstract

The importance of slope stability in civil engineering cannot be underesti-mated, as failure of these structures can result in significant damage to down-stream infrastructure and property. In this study, we used the Bishop slice method, combining both an analytical approach and a numerical approach using the SLOPE/W module of the Geostudio 2018 R2 software. The results obtained from these two methods showed that increasing soil cohesion helps to improve slope stability. The safety coefficients obtained by the analytical method vary between 0.621 and 1.422, while those obtained by the numerical method vary between 0.622 and 1.447, for cohesion values ranging from 4 kPa to 20 kPa. The results obtained by these two methods show a linear rela-tionship between the safety coefficients and soil cohesion. The equation of the analytical method is y = 0.0496x + 0.4407, while that of the numerical method is y = 0.0512x + 0.4357. The results of the analytical approach indicate that a safety coefficient of 1.5 is reached when the cohesion reaches a value of 22 kPa, while the numerical approach shows a safety coefficient of 1.5 reached at a cohesion of 21 kPa. The difference between these two cohesion values can be explained by the number of slices used, which is smaller in the analytical method. However, the equation derived from the analytical method can be used as a general guide to assess the evolution of the safety coefficient of an overloaded slope in long-term behaviour with an increase in cohesion. How-ever, it is important to stress the importance of verification using specialised software based on the finite element method.