Evaluation of Dispersive Properties of Clays to be Used in Embankment of Arsuz - Gönençay Dam

Dispersive clays can easily be eroded when they contact with water having high percent dissolved sodium ion in pores. Colloidal clay minerals in these types of soil produce suspension even in stagnant water by dispersion and decomposition. Use of dispersive clays as an impervious material in embankments and dams can cause serious problems of internal erosion (piping) and failure induced by these problems. In this paper, impervious material areas of Arsuz Gönençay dam are discussed as an example of evaluation of usability of dispersive clays in dam fills. The dam type was selected as zoned earth fill at the stage of feasibility. 80 test pits having the depth of 2.1-7.5 m were performed. In order to determine the engineering characteristics and dispersive properties of impervious soils, samples taken from these pits were tested by using description and engineering tests, pore water analysis, double hydrometer, pin-hole and crumb tests. In case of a stability problem due to dispersibility, design of the embankment of Arsuz-Gönençay dam is revised by the design of clay core with an envelope zone at the downstream, upstream and foundation parts