The Breakage Behaviour of Irregularly–Shaped Particles

This study is an investigation into the breakage behaviour of irregularly-shaped particles through experiments and DEM simulations. Experiments were performed on both uniform and non-uniform (well-graded) soils, while the DEM simulations were performed on 20 particles obtained from outlines of particles from one of the soils. The experiments on the uniform gradings explored the effect of increasing cycles and varying maximum normal stress, initial particle size and material on the breakage behaviour under repetitive compression. The uniform gradings were also sheared in either a small-diameter ring shear apparatus (SRS) or a large-diameter ring shear apparatus (LRS). This produced a non-uniform soil in order to explore the similarities and differences between the breakage behaviour of uniform and non-uniform soils under repetitive compression. The ultimate state grading under repetitive compression was compared with a theoretical terminal state grading (with a fractal dimension of 3). Repetitive compression and LRS tests were also performed on other non-uniform gradings in order to explore the competition between cushioning and particle size. An existing two-dimensional DEM model (described in Alonso-Marroquin & Wang, 2009) was modified in order to allow breakage of the particles. Various assemblies with different bond strengths were repetitively compressed to explore the effect of material strength on the breakage behaviour. It was noted that the breakage behaviours of the uniform and non-uniform soils had similarities, including the formation of a limiting compression curve (LCC) and a reduction of one standard deviation of aspect ratio. These behaviours were also noted in the DEM simulations, showing that the model is suitable for use in the exploration of breakage behaviour