Computation of Seepage through Non-Homogenous Earth-Fill Dams Resting on Pervious Foundations

Abstract

Excessive and uncontrolled seepage through an earth-fill dam is detrimental to its stability. In this study, an empirical correlation was formulated for calculating the rate of seepage discharge through a non-homogenous earthen dam resting on a pervious foundation. Seepage analysis has been performed on SEEP/W program with three different values of each physical and geometrical parameter of the embankment (upstream slope, dam’s height, downstream slope, crest width, core’s slope, depth of pervious foundation, free board, permeability of foundation material, and permeability ratio of core to shell material). Altogether 4374 dam models were analyzed to obtain the seepage datasets. The comparison of seepage values obtained from SEEP/W program with the analytical equations revealed an average percentage error of less than 15 %. Non-linear regression analysis was then performed on the seepage datasets using SPSS-19 software to obtain an empirical equation for seepage calculation. Furthermore, a seepage prediction model was developed using artificial neural networks via MATLAB software. The difference of seepage discharge determined from SEEP/W against its amount computed from the developed empirical correlation and ANN model gave coefficient of determination (R2) of 0.96 and 0.971 corresponding. Sensitivity analysis indicates that a minor change in the dam’s height brings a huge change in the rate of seepage (31.26%), while variation in the upstream slope has the least impact on the rate of seepage (0.93%)