Establishing Long Term Seepage Behavior of Zoned Embankment Dams with Three-Dimensional Seepage Analysis

Paper in proceeding, 2009

Since seepage-related problems are the main cause of more than fourty percent of dam failures, seepage analysis is one of the most important stages in the design process of an embankment dam. Seepage factors must be monitored in the dam’s body, abutments, and foundation during dam's operating life for evaluating safety and conducting risk assessments [1]. Most of e designing analysis is performed two-dimensionally and therefore, little attention is paid to seepage through abutments. On the other hand, the extension of the grout curtain inside the abutments, abutment material properties and dam site inhomogeneities, such as fault and crushed zones are inevitably neglected when performing 2D seepage analyses by this reason, 2D seepage analysis does not reflect real seepage factors and parameters [2]. In this case study, two and three-dimensional finite element (FE) models of an earth-fill dam are generated. Several steady state seepage analyses, as long term seepage behavior evaluation, are performed; the results are compared with the seepage monitored data from the instrumentation system installed in the dam body and foundation. It is concluded that conventional two-dimensional seepage models lead to results that are somewhat unrealistic; instead, three-dimensional (3D) models are much more representative of reality and can be used to evaluate seepage parameters in embankment dams.