Interface shear response of geometry and surface-modified 3D-printed geogrids in sand

Purpose Surface modification in the form of textures has been widely used in polymer sheets and geomembranes to enhance soil-geosynthetic interfacial performance by promoting frictional engagement. Despite the proven benefits of textures in geomembranes, surface modification concepts to geogrids and their interaction with aperture geometry remain largely unexplored. This study aims to examine the coupled effect of aperture geometry and rib surface texturing on the interface shear behaviour of additively manufactured geogrids. Design/methodology/approach Geogrids with square, hexagonal and rhombal-hexagon apertures were fabricated using 3D-printing technique. Three surface textures including cone, strip and chevron patterns were independently incorporated on geogrid ribs. The effect of texture and geometry on stress displacement relationships were evaluated through interface direct shear tests at normal stresses of 50, 100 and 150 kPa. Interface shear resistance, texture efficiency index, surface roughness and energy dissipation were used as performance indicators. Findings The results show that hexagonal apertures exhibited maximum interface coefficient of 1.01 among the shapes. Surface texturing further enhanced the interface response with the chevron texture contributing up to 7.30% compared with untextured geogrids. Correspondingly, textured hexagonal variants recorded the highest energy dissipation, reaching up to 1561 J/m² at 150 kPa. The component wise analytical quantification indicated that increasing normal stress results in a friction-dominated interface response (50–54%) in textured geogrids. The interlocking remained the second major contributor (42–45%). The passive resistance contribution decreased from about 15–22% at 50 kPa to below 5% at 150 kPa. Originality/value The originality of this work lies in exploring different geometry and surface-modified geogrids through 3D printing, which remain largely unexplored in commercial geogrids. The study further provides insights into the interfacial interaction mechanism using both experimental and analytical approach. This can be beneficial in improving pullout resistance and stability of reinforced soil structures under practical field conditions.