Influence of Particle Size on the Long-Term Resistivity of NaCl-Polluted Sandy Soil

The size of soil particles can change the conducting channels through which an electrolyte solution flows in a soil mass, which has an influence on the tortuosity of pores in soil mass, thus further changing the conductivity of the soil mass. By carrying out laboratory tests, the influences of moisture and particle size of sandy soil on the resistivity of sandy soil polluted with sodium chloride were evaluated. Furthermore, the models for analyzing relationships linking the resistivity of sandy soil polluted with sodium chloride with moisture and particle size of sandy soil under experimental conditions were separately established. The test results showed that the resistivity of sandy soil polluted with sodium chloride at different moisture contents linearly decreases with increasing particle size. Based on the Archie resistivity model, the influence of particle size on the resistivity of polluted sandy soil was explored by carrying out laboratory tests. On this basis, the formula (ρ = [(3 − 2ω)(3ω − 35)][(ω + 3) + g]) for predicting the resistivity of polluted sandy soil with changes in moisture content and the particle size of the system of sandy soil is established, where ω, g, and ρ separately refer to the moisture content, particle size, and resistivity of the system, respectively. Finally, by analyzing the influence of particle size on tortuosity, a resistivity model (ρ=Aρωτe(θ)θ) for analyzing the influence of tortuosity on the resistivity of sandy soil is established, where τe(θ), θ, and ρω separately refer to tortuosity, porosity, and resistivity of pore water, respectively.