Development and performance analysis of FBG-embedded geogrids employing 3D printing and UV-curing techniques

Abstract The integration of fiber Bragg grating (FBG) with geogrids has led to the development of intelligent geogrids with exceptional reinforcement and monitoring capabilities, making them highly suitable for geotechnical engineering applications such as slopes and roadbeds. This study introduces a fabrication technique for FBG-embedded geogrids, employing 3D printing and UV adhesive encapsulation. Laboratory tensile and out-of-plane compression tests were conducted to evaluate the repeatability, linearity, and strain-sensing performance of the FBG-embedded geogrids, confirming the reliability of the proposed fabrication method. A coupled fiber-adhesive-geogrid analytical model was developed to elucidate the strain transfer mechanism, and a theoretical strain transfer coefficient was derived. The model was validated through finite element analysis simulations and laboratory experiments, with experimental results at the rib center—showing a strain transfer coefficient of 93.88%—deviating by approximately 6% from theoretical predictions. Further parameter analysis revealed that the elastic modulus, height, width of the adhesive layer and the embedding length significantly influence the strain transfer coefficient. Comparisons with geogrids featuring surface-mounted FBGs demonstrated the superior strain transfer efficiency of the proposed FBG-embedded geogrids. As the encapsulation length decreased from 160 mm to 20 mm, the strain transfer advantage of the FBG-embedded geogrid over the FBG-bonded type increased from 0.6% to 14.3%. These findings provide practical insights into optimizing FBG-embedded geogrid parameters for improved strain-sensing performance, offering valuable guidance for their application in engineering scenarios.