Experimental investigation on mechanical response of soil reinforced by carbon nanotubes and silica dioxide nanoparticles

Abstract

In the present study, three-axis dynamic tests were performed on different samples of soil, and the effect of montmorillonite based carbon nanotubes (CNT) and amorphous silica dioxide nanoparticles presence, density, hydrostatic pressure and moisture percentage on the elastic modulus and equivalent damping ratio of soil was investigated. Considering that in the present research, experimental studies and tests were carried out on three samples of sandy soil reinforced with 2 % volume fraction CNT, sandy soil reinforced with 8 % nanosilica and sandy soil reinforced with 0.5 % CNT and 4 % nanosilica. Also, the optimum moisture percentage has been determined for these types of soils. In general, with the increase of hydrostatic pressure and compaction of sand, the elastic modulus increases, and the amount of increase is different according to the type of nanoparticles. For 1 % applied strain and soil sand, with the increase of hydrostatic pressure from 100 kPa to 300 kPa, the elastic modulus of sand with 2 % CNT and 8 % nanosilica increases by 36 % and 214 %, respectively. This shows the favorable effect of silica nanoparticles on increasing the Young's modulus of sand by increasing the amount of hydrostatic pressure. The effect of CNT on improving the elastic modulus of sand in dry state is much higher than the effect of nanosilica. At 1 % strain and 4 % compaction, adding 2 % CNT to sand increases the elastic modulus of sand about 4 times compared to sand reinforced with 8 % nanosilica.