Implementation of Particle Image Velocimetry for the Evaluation of the Bearing Capacity and the Failure Mechanism of Strip Footings on Reinforced Sand Slope

This study presents a series of small-scale physical model tests designed to investigate the bearing capacity and failure mechanisms of strip footings located on the crest of reinforced and unreinforced sand slopes using Particle Image Velocimetry (PIV) techniques. A total of 30 laboratory model tests were performed under varied conditions of setback distance, relative density, and reinforcement. A single geotextile-reinforced layer was used in this study. PIV analysis was employed as a non-intrusive method to capture the particle soil displacement fields and display the deformation behavior while footing loading. It was found that both the bearing capacity and the failure mode are extremely sensitive to the footing's position proportional to the setback distance ratios (D/B). The footings nearby the slope exhibited unsymmetrical failure wedges with slip surfaces extending to the slope face, resulting in a face failure mode, while the footings with larger setback distances transitioned to bearing capacity failures. The inclusion of a geotextile reinforcement layer improved the bearing performance, particularly at setback distance ratios of D/B = 1 and D/B = 2. The optimum improvement was observed when reinforcement was placed at a depth not exceeding half the footing width. Two distinct modes of the footing on a slope are revealed: peak load resistance and a sudden jerking phenomenon, with the latter consistently associated with slope influence. Overall, the application of PIV provided a deeper insight into the soil–structure interaction and proved to be a reliable tool for assessing the deformation mechanisms in slope-footing systems.