Seepage Analysis through Earth-fill Dams Having Random Fields

Abstract Characteristics of seepage flow through earth-fill dam bodies have been investigated intensively since this phenomenon adversely affects dam stability. In conventional approaches, seepage analyses are commonly carried out in a deterministic manner in which hydraulic and soil characteristics were accepted to be constant. However, possible variations in material characteristics may alter the flow and hydraulic head distribution in the dam body substantially. The aim of this paper is to investigate the effect of uncertainty in the analysis of steady state two-dimensional flow through a heterogeneous and anisotropic earth-fill dam with Monte Carlo simulations. In the course of the study, hydraulic conductivity of the porous media is considered to be a spatially random field which can be characterized by log-normal distribution. The flow domain is presented by a grid and finite difference method is used to solve the governing differential equation of the free surface flow. Hydraulic conductivity values are generated randomly for each node of the grid. The developed probabilistic model is applied to a hypothetical earth-fill dam problem. Then, the results gathered from this model are evaluated statistically, discussed and compared with those obtained from the deterministic solution.

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