Experimental Investigation of Geotechnical Behavior of Collapsible Soils Improved with Nanomaterials

Collapsibility is the sudden volume change of the soil due to the increase degree of saturation. This phenomenon occurs in sands due to the grains sliding on each other and in clays due to the loss of electron bonds between particles. The percentage of soil collapsibility depends on various conditions such as soil type, mineral composition, moisture percentage, dry weight, stress applied during wetting, and the amount of initial soil moisture increase. This paper has been conducted to investigate the effect of nanomaterials on soil collapsibility potential. The soil was selected from the Allahabad region of Kerman in south east of Iran with a high loamy index. For this purpose, Nano-silica, Nano-clay, aluminum Nano-oxide, and Calcium-Nano-Carbonated additives with percentages of 0.5, 1, 1.5, and 2% were used to improve the soil. Double consolidation and direct shear tests were the two main criteria for evaluating the performance of nanomaterials. The results showed that the collapsibility index of the desired soil due to the addition of Nan- clay compared to the addition of calcium Nano-Carbonate, Nano silica, and aluminum oxide causes a greater decrease in the collapsibility index. Furthermore, the results obtained from the SEM images indicate that the collapsible soil has microscopic and macroscopic holes, which the addition of an additive destroys larger holes and creates a correlation between soil particles. This problem reduces the amount of collapsibility index.