Experimental study on the influence of particle morphology on compression characteristics of coral sand in South China Sea

Abstract

Particle morphology is an important physical parameter that influences the engineering properties of coral sand, especially its compressibility. According to the quantitative analysis of particle morphology via the dynamic image analysis technology, a series of one-dimensional compression tests on coral sand and quartz sand with different particle morphology and densities were performed to reveal the effect of particle morphology on the compressibility of coral sand. The results demonstrated that the morphology of particles can be quantified using the shape-angularity group indicator (SAGI), whereas the SAGI of coral sand was greater than that of quartz sand. Coral sand exhibited a yield stress ranging from 1 to 2.5 MPa, and compressive deformations in both coral sand and quartz sand were dominated by irreversible plastic deformation. As the SAGI and densification increased, the number of particle coordination increased while the contact stress between grains decreased, which caused the yield stress of coral sand specimens to increase as well as the compression index and particle crushing rate to decrease. The SAGI of quartz sand particles remained relatively unchanged while that of coral sand particles gradually decreased after crushing, i.e., the coral sand particles developed a more regular shape after crushing.