For a long time, pure plastic clays have been used extensively as the core material of most embankment dams all over the world. Nevertheless, the differences between the stiffness of the fine cohesive core materials and coarse granular shell materials, have caused many construction difficulties and design problems. Adding some granular soils to pure plastic clay will increase the stiffness of the clay material and decrease the differential behavior between these two zones of the earth dams.
In this paper the geotechnical and physical properties of the mixed-clays, prepared for the core materials of the earth dam are explained and described. The behavior of this material in connection with the shell materials of the earth dams are studied and discussed. Finally, for a large storage embankment dam of Karkheh, with mixed-clay core recently constructed in southwestern part of Iran, the overall performance of this material are assessed and justified.
KEYWORDS: dams, embankments, clay, gravel, mixed-clay, field observations, finite element method