Integrated Digital Image Analyses for Understanding the Particle Shape Effects on Sand–Geomembrane Interface Shear

Abstract

This paper investigates the influence of particle shape on the multi-scale shear behavior of sand–geomembrane interfaces through advanced imaging techniques. Two sand specimens with similar particle size distribution but varying particle shapes were scanned using X-ray micro-computed tomography (µCT). The data were processed and analyzed using MATLAB to extract relevant shape parameters like sphericity, roundness, and fractal dimension. Interface shear tests were conducted using a modified direct shear apparatus, which allows image analysis of sand–geomembrane interactions by capturing the kinematics of particles at the contact plane. Additionally, micro-topographical analysis was carried out using a digital profilometer to measure the surface changes of the geomembranes after shearing. By combining the findings from the µCT of sands and micro-topographical analyses of sheared geomembranes, this study aims to gain insights into the macroscopic shear behavior and relate it to the underlying micro-mechanisms. The findings indicated that the increased shear strength observed in irregular particles has a direct correlation with the deeper indentations caused by these particles and the larger localized shear zones associated with these particles.