Effect of Superhydrophobic Nano-SiO2 on the Hydraulic Conductivity of Expansive Soil and Analysis of Its Mechanism

The present work determined the influence of superhydrophobic nano-SiO2 on hydraulic conductivity and pore size distribution expansive soil, analysed mechanism modification between soil from a microscopic view. Superhydrophobic was added to as modifier. Our samples were two types, i.e., unmodified (without nano-SiO2) modified (with 0.2%, 0.4%, 0.6%, 0.8%, 1.0% by weight parent soil). decreased with increasing content. Fourier transform mid-infrared test revealed that some silanols in dehydrated condensed form siloxanes. We inferred can attach onto surface particles hydrophobic membrane, which reduced expansion change distribution. And tests showed volume hydrophilicity SiO2 According Young–Laplace equation, minimum permeable radius calculated hydraulic-conductivity test. With content, decreased. It had an excellent linear relationship containing different contents. Therefore, could effectively reduce changing soil.