An Experimental Study on The Effects of Pore-Fluid Parameters on Microstructural Behavior of Clay Core Materials in Embankment Dams

The abundance of saline water at ground level and their progression to freshwater and onshore sources, landfill leachate chemicals, or industrial plant effluents into the soil are factors that can change the amount and type of soil salinity and, as a result, their geotechnical properties (Ouhadi et al, 2015). Also, due to the size of the large dams reservoirs and the impossibility of changing the axis of the dams due to different constraints, it is possible that after the filling, the dam lake water will come into contact with the salt formations and may cause risks such as changing the geotechnical behavior of the clay core, after exploiting embankment dams. Therefore, due to the presence of contaminants, which is sometimes unavoidable, an understanding of basic mechanisms in modifying the physical and engineering properties of soils under the influence of chemicals or chemical salts is essential (Sen et al, 2017). In general, the concentration of ions affects the intermolecular forces of the soil (ie double-layer repulsion and van der Waals attraction) and the structure of the materials (Weimin et al, 2014; Zhu et al, 2015). As a result, such changes in soil structure alter its engineering properties (Yan and Chang, 2015). According to the extensive studies on the influence of pore fluid on clay soils, however, a comprehensive study from the microstructural perspective with regard to permeability coefficient changes on clay soils has not been conducted. The purpose of this study was to investigate the permeability coefficients and engineering properties of clay soils with a special attitude to clay core in the presence of sodium chloride solution salt as a pore fluid from a microstructural perspective..