Internal Piping Erosion Evaluation of Embankment Dam Considering the Spatial Variability of Soil Properties

Piping erosion is a crucial trigger for dam breaches. However, the effects of inherent spatial variability on seepage properties have not been considered adequately, which could lead to a significant underestimation of the risk of piping-erosion-induced dam failure. Additionally, the complex formation mechanism of erosion pipe formation poses challenges in determining the seepage path. This study proposes a probabilistic evaluation framework which combines a hydraulic-mechanical coupling method with random finite-element analysis. Failure indicators, namely hydraulic gradient and kinetic energy, are utilized within this framework. Based on the proposed framework, the spatial variability of soil properties can be considered effectively, and three cases of dams were analyzed. The results show that the proposed framework can provide a macroscopic visualization of the erosion pipe process. In addition, this framework reveals piping erosion occurrence in approximately 40% of hydraulic samples, whereas deterministic analyses fail to detect any instances of piping erosion. This suggests that deterministic analysis considerably underestimates the risk of piping erosion in practice. The effects of the depth of antiseepage measurements on the formation process of piping erosion are discussed. The results indicate that a medium-depth cut-off wall can meet the impervious requirements and reduce the construction cost in engineering practice.