Particle breakage has a great influence on the mechanical properties of coarse-grained soil materials. In the structure, a particle usually contacts with several surrounding particles when breakage occurs. The crushing mechanism of spherical particles under three-point contact conditions was investigated theoretically and experimentally. In the theoretical analysis, the contact force required for particle breakage is solved by using a stress superposition method based on the ball–ball contact model. To verify the theory, particle contact tests of gypsum spheres under three-point contact conditions were carried out. The experimental results are consistent with the theoretical prediction. Different from the ball–ball contact test, the rupture surface after breakage is a fixed plane passing through all three contact points under three-point contact conditions. Under multi-point contact conditions, the size of the conical core depends on the normal force on the contact point at the moment of particle breakage. Multi-point contact makes particle breakage more difficult, and the stronger the constraint of surrounding spheres, the more difficult it is for the particle to break. Both the theory and the experiment provide evidence that the arrangement of particles affects the overall strength of the coarse-grained soil structure.
Experimental study on particle breakage and fractal characteristics of coarse-grained soil
