The Electrical Analogy technique has been developed for three-dimensional studies of the seepage flow below a dam or a barrage to get the solution of one of the most complicated problems in Civil Engineering where when designing a structure on homogeneous foundations, an impervious rock layer of irregular shape is encountered in sub-soil below the foundation. The studies reported (1) before relate to cases where the layer is of uniform shape (horizontal or sloping) and could be tackled as cases of advanced applications of the electrical method in the two-dimensional field. But for a case of an irregular stratification like the above, the solution of the problem connected with the design of underground parts of a hydraulic structure (known as sub-structure) has been attempted by using the electrical method for the three-dimensional study of this nature and this is the only means to obtain the solution of such problems.
