Extreme Hydraulic Gradient Statistics in Stochastic Earth Dam

Abstract

The existence of large hydraulic gradients in regions of an earth dam where fine-grained soils are inadequately filtered can sometimes lead to internal erosion and piping failure. This paper investigates the stochastic nature of hydraulic gradients through two different earth dam cross sections, both with simple drains. In particular the magnitude and location of maximum hydraulic gradients are studied via Monte Carlo simulation to derive their probability distributions and assess their variability. These results can be used to guide designers with respect to minimizing the risk of internal erosion in the presence of uncertain soil permeability. The effect that the stochastic nature of the permeability field has on the hydraulic gradient distribution is compared to hydraulic gradients obtained in the deterministic case. This enables an evaluation of the importance of considering permeability randomness in the design process.