Hydrological uncertainty in stochastic heterogeneous soil slope

Understanding the impact of hydrological uncertainty on soil slope stability is crucial for assessing slope failure risks in heterogeneous terrains. This study aims to investigate how heterogeneity in hydraulic properties influences slope stability and groundwater dynamics.

A total of 3,500 realizations of hydraulic conductivity fields were generated, with heterogeneities inclined at a 20-degree dip to mimic realistic subsurface conditions. To generate stochastic hydraulic conductivity fields, we employed a Gaussian random field model with specified mean, variance, and spatial correlation lengths. These fields were transformed into log-normal distributions to represent the natural variability of hydraulic conductivity in soils. Similarly, saturated water content was also generated as a random field to account for its spatial variability and its correlation with hydraulic conductivity heterogeneity. Using FEMWATER, we simulated unsaturated and saturated flow processes for each realization, capturing the spatial and temporal variability of water movement within the slope. Uncertainty analysis was then performed to evaluate the statistical properties of the flow and groundwater levels, including variance, covariance, and cross-variance.

The results highlight the variability in groundwater flow patterns and the envelope of groundwater levels under stochastic conditions. The uncertainty analysis revealed significant influences of hydraulic conductivity on flow behavior, characterized by variance, covariance, and cross-variance. These findings provide a comprehensive understanding of the stochastic behavior of hydrological processes in heterogeneous slopes and contribute to a more robust framework for predicting slope stability under uncertain hydrological conditions.