Particle Crushing and Morphology Evolution of Saturated Crushed Gangue under Compaction

Abstract

In this research, the deformation, particle crushing, and morphology evolution of saturated crushed gangue under variable axial stresses (0, 2, 4, 8, 12, 16, and 20 MPa) were investigated by performing a series of laboratory tests with our self-designed compacting device. The research results showed that the relationship between compression modulus and axial stress can be expressed by an exponential function. The relative breakage varied from 0 to 0.3685 and increased monotonously with the increase of axial stress. The relation between relative breakage and axial strain was described by a linear function. The particle circularity varied from 1.179 to 1.361 and decreased gradually with the increase of axial stress. When the axial stress increased from 0 MPa to 2 MPa, the relative breakage increased rapidly by over 39.15% of the total increase, and the particle circularity of large particles in the range of 15–20 mm sharply decreased by over 48.34% of the total decrease. 2 MPa was a key value in controlling the particle crushing of the saturated crushed gangue during compaction. Particle crushing was predominantly divided into three types: fracture, crushing, and grinding. At the early stage of compaction, fracture and crushing took place in large numbers. At the end, grinding was the main form of particle crushing. The axial strain was influenced by the initial gradation, and a larger Talbot exponent corresponded to a larger strain. However, the initial gradation had little effect on the relative breakage.