Estimation of the Phreatic Line for One-Dimensional Unsteady Seepage Flow Using Similarity Transformation

An approximate solution that can predict phreatic line through similarity transformation by directly using second-order nonlinear partial differential equations, which is used for one-dimensional unsteady seepage flow analysis is proposed. The proposed approximate solution, derived using similarity transformation, confirms the change of the phreatic line over time in the earthen dam. To evaluate the applicability of the approximate solution, the prediction of the phreatic line using similarity transformation is then compared with that of conventional methods by Kozney, Casagrande, and Schaffernak-Iterson, as well as with numerical and experimental test results. It is noted that the approximate solution can predict the phreatic line reasonably well in homogeneous earthen dams.