Evolution of particle morphology of quartz sand during one-dimensional compression
Ting Yao, Xin Xing, Wei Li
Abstract
Particle breakage alters particle size, shape, surface roughness , and co-ordination number, which in turn changes macro-mechanical behaviour including compressibility and shear strength . This study conducted a series of one-dimensional (1D) compression tests on quartz sands with different initial void ratios , ending the tests at various stress levels up to 13.5 MPa. The size and shape of particles were quantified using a dynamic particle shape analyser, while the surface roughness of thirty randomly selected particles for each sample was measured by an optical interferometer and quantified using flattened root-mean-square roughness ( RMS f ). The results demonstrate that a unique normal compression line is defined due to extensive particle breakage, with denser sample exhibiting a higher yield stress. Prior to yielding (vertical stress < 6 MPa), the changes in the three shape descriptors are limited, as the primary particle damage modes are abrasion and grinding . Conversely, at high stress level, a greater number of particles undergo splitting or explosive damage, leading to the creation of more irregularly shaped particles. The occurrence of plastic deformation at particle asperities under one-dimensional compression is identified, resulting in a decrease in surface roughness. This study highlights the significant role of the initial void ratio in shaping the evolution of surface roughness of particles under 1D compression.