Abstract
In this study optical flow method is used for soil deformation measurement in laboratory tests. The main objective was to observe how the deformation distributes along the whole height of cylindrical soil sample subjected to torsional shearing (TS test). The experiments were conducted on dry non-cohesive soil samples under two different values of isotropic pressure. Samples were loaded with low-amplitude cyclic torque to analyze the deformation within the small strain range (0.001-0.01%). Optical flow method variant developed by Ce Liu (2009) was used for motion estimation from time-ordered series of images. This algorithm uses scale-invariant feature transform (SIFT) for image feature extraction and coarse-to-fine matching scheme for faster calculations. The results show that while the displacement values change approximately monotonically along sample's height, displacement field is very different for samples under different isotropic pressure. Moreover, the deviations from assumed linearity distribute differently during different stages of the same TS test.
Abstract (translated)
URL
https://arxiv.org/abs/2101.07005