Slope reliability analysis of high rockfill dams considering stress-coupled spatial variability of friction angle

Due to the spatial variability of friction angle, which is related to the stress in the rockfill dam, its impact on slope reliability is significant and cannot be overlooked when evaluating the risk of instability in rockfill dams. By combining the finite element method with Karhunen-Loeve expansion, the impact of material parameter spatial variability on slope reliability can be comprehensively considered. However, in the slope reliability analysis of high rockfill dams, the number of random variables required to discretize the material parameter random fields is substantial. This can affect the accuracy of the reliability calculation results. To address this issue, a method for slope reliability analysis of high rockfill dams considering the stress-coupled spatial variability of friction angle is proposed in this paper. By combining the proposed method with a concrete-faced high rockfill dam, the effect of dam stress distribution on the spatial variability of friction angle is revealed. Furthermore, the slope reliability is calculated under both uncorrelated and correlated conditions for the nonlinear strength parameters. The results show that this method effectively reduces the dimensionality of the input variables. Furthermore, the optimal surrogate model constructed using this method achieves high prediction accuracy, significantly improving the reliability calculation accuracy.