Visual and quantitative investigation of the settlement behavior of an embankment using aerial images under large-size field loading

In this study, the settlement behavior of the embankment due to the surcharge loading have been visually and quantitatively investigated. The spatial variation of settlements of an oversized embankment have been monitored using aerial images taken at intervals. In order to achieve the deformations due to the surcharge loading in the field, two topographical three-dimensional models (before and after surcharge loading), derived from aerial images and ground control points, have been generated and compared. The aerial images were acquired by an unmanned aerial vehicle with autonomous flight capabilities. The topographies were compared by generating two cloud point models. The deformations, determined from the comparison of two cloud points, were visualized by assigning an intensity value, which was calculated based on the three-dimensional variations of each data point. The surficial settlement profiles nearby the surcharge load have been computed. It has been concluded that centimeter level accuracy on surficial settlement has been achieved by low altitude aerial images, although the illumination condition of the area has an influence on the measurements.