Quantitative characterisation of the geometry of discret particles

A new technique is described to quantify particle shape and angularity using an image analyser. The method relies on discretising the two-dimensional projection of the particle and comparing the projected outline with that of a standard geometric shape, namely a circle. Two new parameters for particle shape and angularity were formulated and their values were determined for various materials. The relationship between the new parameters and large-strain (steady-state) internal friction angle as well as pluviated void ratio was examined. Overall, the results indicate that as shape and angularity parameters increase, the drained friction angle and pluviated void ratio increase. In addition, shape and angularity were found to influence the measured maximum void ratio and, to a lesser extent, the minimum void ratio.