Aske Mikkelsen

I dont know if this topic is placed in the rigth category, but if not please redirect it I am student in geotechinal engineering at Aarhus University and I am doing an experiment where I apply vertical load to a slope in granular soil. The experiment is made in a 1.6m x 1.6m concrete box and I am interested in measuring the movement of the soil particles during excecution of the experiment. I was thinking about tagging some of the particles and then tracking them with some kind of tracking device (radio active e.g), but I have no idea if that is possible. A more simple way is much appreciated too, such as painting some of the particles and measure the placement of the particles before and after, but I dont know if that is too much work for too imprecise results. Regards, Aske Mikkelsen