Effect of Statistically Anisotropic Undrained Shear Strength on the Probability of Slope Failure

Due to large-scale geological deposition processes, slope structures are often stratified, which means that the spatial distribution of the parameters involved in slope reliability evaluation is statistically anisotropic. This paper studies the effect of the statistical anisotropy of undrained shear strength on the probability of slope failure (p(f)) based on the Monte Carlo simulation. The results show that for the horizontally layered slope, the larger the horizontal correlation scale of undrained shear strength (lambda(x)) is, the larger p(f) is, especially when lambda(x) is smaller than the slope length; for the vertically layered slope, the larger the vertical correlation scale (lambda(y)) is, the smaller p(f) is, especially when lambda(y) is smaller than the slope height. Additionally, the mechanism of the above results is discussed by analyzing the displacement distribution at different correlation scales. The findings indicate that in the reliability evaluation of undrained slopes in stratified structures, either underestimation of lambda(x) or overestimation of lambda(y) leads to an unconservative estimate of p(f), resulting in an overestimation of the slope stability.