Laboratory Study of the Effect of Clay and Silica Nanoparticles on the Behavior of Silty-Clay Soils in Mashhad

According to the expansion of cities, the necessity of high-rise buildings construction and the need to retrofitting the old buildings is inevitable, particularly in metropolises such as Mashhad with expanded urban areas and neighbor areas of Imam Reza shrine built on the fine-grained deposits, the necessity of improvement and reinforcement of soil is evident. Nanotechnology can be significantly efficient as one of the most useful modern technologies in the recent century to meet the needs of the construction industry. The technology has a significant effect on the improvement of strength and mechanical parameters of soil because of a considerable increase in particle surface. In this regard, this study has investigated the effect of adding clay nanoparticles of type Montmorillonite and Silica of type "S" on the strength and mechanical parameters of silty-clay soils adjacent to Imam Reza's Shrine using laboratory studies. The results showed a significant increase in shear and compressive strength parameters and a decrease in settlement of soil in the Nanosilica-improved samples compared to nanoclay-improved ones. In this way, adding 1% nanosilica and 2.5% nanoclay could cause a 620 and 134% increase in bearing capacity of silty-clay soil, respectively.