The pressing need to recognize and track individual sand particles in fundamental research on geomechnics has promoted the rapid development of particle tracking techniques in recent years. This talk presents the latest development of a few innovative pattern recognition techniques for identifying and atching intact and crushed sand particles. These techniques include particle volume-based tracking (PV-track), particle radius -based track (PR-track), spherical harmonics-based tracking (SH-track) and point cloud -based tracking (PL-track). Specifically, PV-track and PR-track are suitable for tracking particles within a neighborhood area but the tracking accuracy and reliability decreases with the increasing deformation of the sand specimen. SH-track is a much more powerful and robust technique which makes use of the SH invariant describing the multiscale morphological features of sand particles. However, the common limitation of PV-track, PR-track and SH-track is that they can only be applied to intact particles with solid structures (i.e., non-porous structure). In contrast, PL-track can deal with both intact and crushed sand particles and has been successfully used to match a group of crushed quartz particles. More importantly, PL-track can be integrated with machine learning techniques to achieve intelligent recognition and tracking, and has been successfully used to identify a group of highly porous carbonate sand particles. The implementation of all these particle tracking techniques is based on the X-ray microtomography scanning of a miniature specimen of sands, which provides the source data for the pattern recognition exercise.
Jianfeng Wang is currently an Associate Professor at City University of Hong Kong. He is internationally well known for his works in the field of micromechanical characterization and modelling of granular soils. He has been awarded the prestigious international prizes of 2011 Geotechnical Research Medal (UK Institution of Civil Engineers) and 2010 Higher Education Institutions Outstanding Research Award - Natural Science Award (the Ministry of Education of China). His research has attracted over 7 million HKD of external grants including the Research Grant Council (RGC) of Hong Kong SAR and National Science Foundation of China (NSFC). He is currently serves as a Scientific Editor of Journal of Rock Mechanics and Geotechnical Engineering (The Chinese Academy of Science), and an Editorial Board Member of Soils and Foundations (The Japanese Geotechnical Society).
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