Abstract
Stabilization of soils with additives is a widely used improvement method. With the mass production of nanomaterials in various fields, and their application in geotechnical engineering discipline, it is essential to investigate the characteristics of soils mixed with nanoparticles and examine their effect on the various chemical, physical, and mechanical properties of soils. This research is an attempt to examine the performance of clayey soils treated with nano-silica (NS) as an additive. To achieve this goal, the Atterberg limits, standard compaction, permeability, and unconsolidated undrained (UU) tests were performed on a fine-grained soil mixed with 1, 2, 3, and 4 wt% of NS. Scanning Electron Microscopy (SEM) was also used to observe the texture variation of NS-treated and non-treated samples. The X-Ray Diffraction Fluorescence (XRF) test was conducted on the soil specimen to find out the percentage of existing elements. The results showed that adding NS to the soil decreases the plasticity index, increases the maximum dry density, increases the optimum moisture content, and reduces the permeability coefficient. It was found that the permeability coefficient of the samples which were treated with NS, decreased, compared to that of the natural sample. Furthermore, an additional 60–68% maximum strength was achieved by conducting triaxial UU tests on the sample treated with 2% NS under a confining pressure. Additionally, the cohesion and internal friction angle of NS-treated sample increased in comparison to the sample not treated with NS. Furthermore, the SEM images of NS-stabilized samples represent the physical and chemical bonds between soil particles and NS