Seepage through earth dam with clay core and toe drain: the Casagrande–Numerov analytical legacy revisited

Seepage through a zoned earth-filled dam with a vertical clay core, two permeable shoulders and toe drain are studied. Seepage through the core and the downstream shoulder are coupled. The flow rate and phreatic surface are found. The hodograph method is used, viz. a conformal mapping of a rectangle in the complex potential plane onto a circular triangle. Numerically, MODFLOW 2005 simulated seepage with the refraction of the streamlines at the interfaces between the core and both shoulders.