Effects of particle size on the particle breakage of calcareous sands under impact loadings

Abstract

Particle breakage of calcareous sands under impact loadings, closely related to marine and geotechnical engineering, has attracted a great deal of attention. This paper presents the results of a study on the effect of particle size on particle breakage characteristic of calcareous sands that underwent different degrees of particle breakage. Calcareous and quartz sands of four different particle size (i.e., 5.00–2.00 mm, 2.00–1.00 mm, 1.00–0.50 mm and 0.50–0.25 mm) were subjected to impact loadings with different input energies. By defining particle size distribution (PSD) using fractal methods, it is found that the PSD evolution of quartz sands is similar to that of calcareous sands. Compared with quartz sands, the particle size related fractal behavior of calcareous sands is more easily affected by the initial particle size. The compressibility of calcareous sands is greater than that of quartz sands. The volumetric deformation of the above two kinds of sand can be divided into three typical stages: initial compression stage, failure stage and stability stage. Unlike calcareous sands, quartz sands can reach the stability stage at a low input energy. For calcareous sands or quartz sands, the breakage sensitivity of fine particles is more significant than that of coarse particles. This could be attributed to their different coordination numbers. Particles with smaller coordination numbers undergo larger impact loadings, resulting in the higher breakage sensitivity than particles with larger coordination numbers. Finally, an empirical model for estimating the degree of particle breakage by volumetric deformation is proposed.