SEEPAGE ANALYSIS THROUGH PERMEABLE FOUNDATION OF FINITE DEPTH UNDER A WEIR USING FEM

Abstract

Hydraulic structures such as weirs and barrages are generally designed on the basis of Khosla's theory. One of the assumptions on which Khosla's theory is based is that the depth of permeable stratum below the foundation is infinite. However, in reality the depth of permeable stratum is generally of limited depth. Moreover Khosla's theory is applicable if the foundation is homogeneous which is not the case in a number of instances. In actual situations foundation strata varies with depth. The seepage condition in such situations can be worked out by using the electrical analogy, the finite difference or finite element methods. With the computing facilities available these days, finite element analysis can be carried out in such cases. Analytical studies have been conducted by finite element method to determine the seepage pressure and exit gradient under a standard form that is a horizontal floor with three rows of pile lines. In one case of the finite depth of one homogeneous stratum has been considered and the results are compared with the Electrical Analogy results. In another study the effect of stratification of foundation has also been studied.