Numerical Study of Three-Dimensional Seepage Effects on the Design of Horizontal Drainage in Homogeneous Earth Dams

Statistics show that about ۴۰ percent of earth dams’ collapse is due to the problems caused by their seepage. The flow of water from the body of earth dams causes leak force, pore water pressure and hydraulic gradient, which may cause problems such as downstream slope instability, leaching of dam materials, internal erosion, dam displacement, liquefaction, stirrup, piping and flake of dam’s downstream side. So, seepage analysis is one of the most important steps in design and safety control of an earth dam. One of the methods for designing the seepage of an earth dam, is using three-dimensional analysis to provide designers a more real view of the amount of seepage. This is because in narrow valleys that transversal section of the dam is highly variable along the valley, or in the case that a special form of heterogeneity exists in the dam site, two-dimensional analysis can give results much away from reality that results in an uneconomical design or non-utilizable dam. Drainage is a part of dams that is affected by this difference, so its design is an important step in designing dams. In this paper, the case study of seepage analysis using finite element method with saturated and unsaturated flow assumptions has been considered on the Freeze paper of ۱۹۷۱. Finally, studying the results of seepage analysis in the case of three-dimensional steady flow, drainage design is performed.

کلیدواژه ها:

Earth Dam ، Seepage Analysis ، Drainage ، There-Dimensional Model ، Case Study