Effects of anisotropy in correlation structure on reliability-based slope stability analysis of a landfill

Abstract

In this study, a reliability-based analysis of slope stability in a landfill considering the spatial variability of shear strength (c and φ) and unit weight ( γ) of municipal solid waste was performed using the random finite difference method. The effect of the anisotropic correlation (AC) structure of random variables including c, φ, and γ on mean and coefficient of variation (CoV) of safety factor values was investigated using Monte Carlo simulation. Also, probability of failure was determined through probability distribution fitting to a series of safety factor data. The results showed that the AC of the random variables has a significant effect on the stochastic safety factor of landfill slope. In general, the mean of the stochastic safety factor decreases with increasing horizontal and vertical correlation lengths (CLs). Also, the CoV of the safety factor increased with increase in horizontal or vertical CLs or both. Moreover, it was found that failure probability increases with an increase in the horizontal and vertical CLs and assuming isotropic structure for the correlation of random variables leads to the underestimation of failure probability. Overall, the results indicate that assuming an AC structure results in different failure mechanisms in the landfill slope, which are different from the deterministic cases.

Reliability of Municipal Solid Waste Landfills within the Eurocode Framework

“…where X m is the mean value of the property and COV X is the coefficient of variation in the property. In structural reliability analyses, variables with a larger coefficient of variation exert a greater impact on the outcomes, whereas variables with a smaller coefficient of variation have a lesser impact [2,29]. Consistent with this principle, in the reliability analyses conducted within this study, both the friction angle and cohesion are treated as random variables, and the MSW unit weight is considered a constant.…”

“…Therefore, various potential operational issues, such as high leachate levels, gas build-ups, and inadequate shear strength at the liner-MSW interface, have not been considered in these analyses. Analyses on simplified models, which include similar assumptions, are also introduced by other authors in studies that explore similar topics [2,12,22]. The model of the MSW landfill slope used in this study is shown in Figure 1.…”

“…considered in these analyses. Analyses on simplified models, which include similar assumptions, are also introduced by other authors in studies that explore similar topics [2,12,22]. The model of the MSW landfill slope used in this study is shown in Figure 1.…”

“…Environmental challenges, land constraints, and global governmental regulations are prompting engineers to optimize the use of existing landfills and to design new ones with greater volume and height. The increase in landfill capacity highlights the critical importance of their geotechnical performance [2].…”