Optical Flow Analysis of Internal Erosion and Soil Piping in Images Captured by the VisCPT

Internal erosion and soil piping are caused by the migration of fine soil particles through a skeleton of coarse grains or by progressive mass movement of soil grains under the tractive forces produced by concentrated subsurface flow, which may lead to the failure of dams and levees. The ability of the Vision Cone Penetrometer (VisCPT) to record internal erosion and soil piping in the laboratory and in-situ has previously been reported. The present paper focuses on developing a video-processing algorithm to quantify the soil particle motions. An optical flow technique is adopted to compute particle migration velocity fields. This makes it feasible to detect, track and quantify the movement of soil particles by the VisCPT. The research defines the eroded area percentage (EAP) and the sum of the absolute velocities of mobilized fine soil particles (SAV) which may eventually be used to quantify soil erosion and piping susceptibility.