A customized fragment for seepage beneath a dam with a vertical wall

Based on the method of fragments for the analysis of steady confined seepage, a customized type E fragment is developed, with results presented in the form of charts for the estimation of seepage quantities and exit gradients under embedded water-retaining structures with a vertical cut-off wall. The type E fragment is shown to be an extension of previously derived type A and type D fragments, allowing for both embedment and a cut-off wall. The charts are generated using finite element analysis and cover both isotropic and anisotropic permeability cases. Validation of the fragment is confirmed by comparison with existing method of fragments and full finite element analysis. The charts are shown to predict the flow rate and exit gradient more precisely than existing methods of fragments. The design charts presented in this paper cover a wide range of confined flow problems of practical interest. © 2021 The Author(s).