Seepage through Dams with Horizontal Toe Drain

The position of the free surface in a homogeneous and isotropic earth dam with a horizontal toe drain is determined using complex function theory and conformal mapping of the inverse velocity, and complex potential planes into the same upper half of an auxiliary plane. Calculations are carried out for dams with an angle between the upstream face and horizontal equal to 15°, 30°, 45°, 50°, and 90°. The results are partly given in the form of graphs from which the seepage quantities, the length of the drains, and the values of the unknown parameters that are necessary for calculation of the coordinates along the free surface can be obtained. Comparisons are made between the computed free surface, profiles and the profiles obtained by other investigators.