UJI DISPERSIVITAS BAHAN TIMBUNAN BENDUNGAN DURIANGKANG

Abstract

Dispersive clays have been identified as soils which highly erosive because they have a higher percentage of dissolve sodium in their pore water than ordinary clays. The dominant sodium ions increase the thickness of the diffused double water layer surrounding the individual clay particles. This causes the repulsive forces to exceed the attractive forces so that the individual clay particles go into suspension in the presence of water. Their detrimental effect on the performance of dams, canals has been recognized. Piping in earth dams which lead to the failure of dams due to the presence of dispersive clays has been identified in Australia, United States, South Africa and many countries throughout the world. This research presented the tests using various available methods to identify the degree of dispersive of embankment material for Duriangkang dam, the first estuary dam in Indonesia. Analyses to the results were also discussed. The decision not to include the suspected dispersive and moderate dispersive clays in the embankment of Duriangkang dam was taken in order to minimize the risk of eroded and piping progress in the dam body.