Preliminary evaluation of the technical feasibility of using different soils in waste disposal cover system



Engineered cover system is considered as an essential component required by the long-term safety concept for radioactive waste disposal, landfills, and contaminated land. In this article, a design procedure that can be used in the prebasic design phase for the investigation of the technical feasibility of candidate capillary barrier materials from hydrological and geomechanical point of view has been proposed. The proposed procedure relays on using well-developed pedotransfer functions (PTFs) to estimate some important engineering properties. A case study to illustrate the procedure was performed using three different soil samples taken from the radioactive waste disposal site in Egypt. The results of the preliminary characterization of the samples were used as input parameters for the selected PTFs. The results of the particle size distribution (PSD) analysis were used to quantify the uniformity of the PSD and to identify the internal stability of the studied samples. The estimated soil hydraulic properties values were found to be comparable to that of the literature; the critical and breakthrough pressure head were evaluated. The results indicate that the suggested capillary barrier profiles will work successfully in dry conditions, and the finer layer thickness was calculated based on the storage capacity of this layer. The precompression stress was estimated, and it was found that the clay is unstable in terms of soil compaction. The factor of safety was calculated, and it was found that the sandy loam has higher safety factor for all studied slope angles. © 2010 American Institute of Chemical Engineers Environ Prog, 2011