Multi-scale understanding of sand-geosynthetic interface shear response through Micro-CT and shear band analysis

• Published in: Geotextiles and geomembranes Vol. 51; no. 3; pp. 437 - 453
• Main Authors: Khan, Rizwan, Latha, Gali Madhavi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2023
• Subjects: Digital image correlation; Geosynthetics; Interface shear; Laser profilometry; Micro computed tomography; Shear band; Geosynthetics; Micro computed tomography; Interface shear; Shear band; Digital image correlation; Laser profilometry
• ISSN: 0266-1144; 1879-3584
• DOI: 10.1016/j.geotexmem.2023.01.006

To understand the process of mobilisation of shear strength in sand-geosynthetic interfaces at a fundamental level, it is essential to precisely characterize the size and shape of the grains and the shear-induced surface changes in geosynthetics. In the current study, shear behaviour of dilative and non-dilative geosynthetics interfacing with sands of different morphological characteristics was analysed through interface shear tests and a gamut of digital imaging techniques. 3D shape parameters of sands such as sphericity, convexity, roundness, aspect ratio, and roughness were quantified at different scales using X-ray micro computed tomography (μCT) and optical profilometry. Interface shear tests revealed higher peak and residual friction angles for particles with greater irregularity, angularity, and surface texture. The surface texture of geotextile surfaces resulted in higher interface friction and higher vertical displacement compared to geomembrane surfaces, which showed completely non-dilative behaviour. Surface changes in geomembranes were quantified using laser profilometry. High resolution images obtained at different stages of shearing were analysed for quantifying the shear zone thickness using digital image correlation (DIC). Thickness of the shear bands, microscopic shearing mechanisms and shear strength are correlated to the multi-scale shape parameters of sands and surface changes in geosynthetic surfaces. •Shear tests are carried out on sands, sand-geotextile and sand-geomembrane interfaces.•Sand particle shape is characterized using μ-CT scanning and spherical harmonic particle reconstruction.•Shear zone thickness is measured using DIC correlations.•Surface changes to geomembrane are quantified using laser profilometry.•Particle shape effects on interface shear strength is quantified.