Examination of the Physico-chemical Composition of Dispersive Soils

When it comes to flood protection, the established method is to use an impermeable material in dikes, to prevent seepage. This material is usually some type of clayey soil which is considered as watertight and erosion-resistant. Despite that, in many occasions not only seepage, but the failure of the dam occurred due to surface erosion, because dispersive behavior is barely investigated, and their presence are not considered during the phase of design. The term “dispersive clay” refer to a cohesive soil, which has an unfavorable property compared to other clays. Therefore the application of these kind of clays in flood protection structures, like dikes cannot be considered as a solution for the seepage problems. Dikes constructed from dispersive soils often fail to achieve the main idea of flood protection: keeping the downstream face relatively dry. Earlier experiences stated that the dispersive behavior is related to the physico-chemical composition of the soil, therefore in this paper a few Hungarian soils, which are identified as dispersive are examined with geotechnical, agricultural and phase analytical methods.