Transparency optimization of transparent soil based on fluid ratio and particle size

High transparency is the prerequisite and guarantee for conducting large-scale transparent soil visualization experiments under complex conditions. In order to evaluate and configure transparent soil with high transparency, this study takes transparent soil as the research subject, with n-dodecane and No. 15 white mineral oil as pore fluid and fused silica sand as aggregate. We proposed a modified formula for the configuration of Christensen transmissivity based on optical principles, and verified the transparency optimization method through experiments. Results indicate that: ① Differences in solid-liquid refractive index and the particle size of solid particles are factors influencing transparency related to configuration of transparent soil itself. ② For transparent soil samples with the thickness of 100 mm, the upper and lower limits of the differences in refractive index were ±0.002 between solid and liquid. Within the theoretical temperature range of 0~50 ℃ (under normal pressure), for every 1 ℃ increase, the refractive index of the pore fluid decreased by about 0.000 4. ③ The ideal refractive index of pore fluid (1.458 5) at higher temperatures corresponded to a lower volume ratio of alkane to oil. ④ Transparent soil in the grade of light absorption coefficient in the colorless optical glass was between Grade 5 and 6.