Bottom sediments from a dam reservoir as a core in embankments-filtration and stability: A case study

Abstract

A possibility of using bottom sediments from dam reservoirs in earth structures was considered. Sediments from the Rzeszow reservoir (Poland) were used as research material, which, according to geotechnical standards, were classified as low permeable silt with high organic content. As fine, cohesive soil with a low coefficient of permeability, the sediments can be used in sealing elements of hydraulic engineering embankments. In order to verify the suitability of the sediments, stability and filtration calculations were carried out for embankments with a sealing in the form of a core made of the sediments. It was stated that by using a core made of sediments, the volume of seepage on the downstream side during continuous or variable backwater was significantly lower in relation to an embankment without a core, and the phreatic line did not extend to the downstream slope. It is estimated that, in the case of a planned dredging in Rzeszow Reservoir, the amount of dredged sediment would exceed 1.5 million m3, and therefore, the possibility of their economic use is essential. The search for materials that could replace natural soil in earthen structures is an important issue from both the ecological and economic points of view.