Uplift and Seepage under Dams on Sand

The basic principles of flow under dams on sand are presented briefly in this paper in the hope of stimulating scientific study of this much neglected subject. Analytical methods applicable to some familiar types of foundations, and graphical and electric analogy methods of general application are described, by which can be determined the theoretical laws governing: (1) The hydrostatic pressure along the foundation contact; (2) the hydraulic gradient with which the water escapes upward at the toe; and (3) the approximate leakage under the structure. These theoretical laws are to be used as scientific nuclei around which to build future experimental data and field observations to the end that the order of magnitude of field variations from scientific principles and the safe coefficients or factors of safety for practical applications may be determined.