Abstract: The main study of this paper focus on the problems that the absolute breakage amount of particles in a certain size range can not be acquired and the hidden breakage amount can not be considered in the particle breakage rate in a sample. Three kinds of calcareous sands, rich in coarse, medium and fine sands respectively, are subjected to the confined compression test. Particles with different sizes are dyed in different colors, and pictures contain the breakage information of particle in all certain particle size range are taken. Then, the Image J software is employed to segment and binarize these pictures and records the area of particles with different colors, which is used to calculated the content of the particles with different colors after failure. Finally, an accumulated particle breakage Ba, which considers the absolute breakage amount of particles in a certain size range, is proposed. Test results show that with the increase of pressure or the concentration of particle distribution, overlapping breakage of samples increases. Among these calcareous sand samples consisting of particles in different sizes, the sand in intermediate particle sizes (0.25-1 mm) is breakable, and edge and corner breakages are the dominant break pattern in the particles with different sizes. The accumulated particle breakage Ba is larger than the relative breakage Br, and has a linear relationship with the logarithmic value of vertical pressure. The study of this paper provides a new method for the research on particle breakage.

Key words: calcareous sand, particle breakage, dyeing tracking method, particle image segmentation, accumulated particle breakage