Abstract
This study presents a new approach for estimating the relative density (D(R)) of sand using particle configuration parameters from soil images. Focus was on utilizing soil assembly images depicting particles in group configuration. Soil images at various D(R) were prepared and adopted to analyze the assembly and shape configurations. The values of particle diameter (d), perimeter (p) and total perimeter (p(tot)) obtained from soil assembly images at different D(R) were evaluated and compared with those of individual bulk particles. As D(R) increased, d and p decreased, while p(tot) remained similar. The sphericity (S) and roundness (R) of soil assemblies in group configuration were evaluated. It was found that S was smaller than for bulk particles, whereas R was similar. The number of particles (NoP) from soil assembly images was newly introduced as an indicator to volume characteristics. Through the correlation analysis, a close relationship of D(R), p(tot) and NoP was found, where p(tot) increased linearly with NoP. Based on this finding, a unified correlation model utilizing combined parameters of p(tot) and NoP was established for estimating D(R). Verification tests were additionally conducted using different types of sands, confirmed the validity and efficacy of the proposed image-based D(R) estimation method.