Tridimensional seepage through a dam foundation

Abstract

This paper concerns a method for the tridimensional study of the seepage in porous, heterogeneous and anisotropic media, being specially applied to the study of dam foundations.

The general equation of seepage defining phenomenon

(δ²h/δx²) kx+(δ²h/δy²) ky+(δ²h/δz²) kz=0

is integrated by finite differences. The definition of the upper seepage surface is obtained through sucessive approaches.

The occurrence of springs and some saturated zones in the natural ground downstream form the foundation by the toe of the right bank of the Massingir dam, in Mozambique, made pertinent the application of this method. Different hipotheses of the layering and geotechnical characterization of the foundation were formulated, based on the available information. This work enabled to quantify the efficiency of some studied solutions, regarding the flood and percolation gradients. The results of this study were an important element in the option taken for the performance of the diaphragm wall through alluvionar formations of the dyke.