Influence of the particle morphology and internal porosity characteristics of coral sand in the South China Sea on its limit void ratio

Abstract

An essential physical parameter for describing the characteristics of cohesionless soil is the limit void ratio. A type of cohesionless soil made up of pieces of coral skeleton is known as coral sand. The limit void ratio of the aggregate will be significantly impacted by its distinct particle morphology and internal pores. The influence of particle morphology and internal pores on the limit void ratio of coral sand is investigated in this paper based on the quantitative evaluation of particle morphology and internal pores. The comparison test with natural quartz sand, artificial broken quartz sand, glass balls, and other loose aggregates reveals the impact of mineral composition on aggregates' limit void ratio. The findings indicate that: (1) the roundness of sand particles increases with particle size. (2) The roundness and internal porosity of the sample show an upward trend with an increase in the content of cube-shaped particles. (3) The internal porosity of particles is controlled by the shape of the particles. The internal porosity of cube-shaped particles is the highest, with an average internal porosity of 20.19%, followed by bar-shaped particles, and the lowest in flake-shaped particles. (4) The particle size will not affect the limit void ratio. The limit void ratio of quartz sand and glass ball has a linear negative correlation with roundness, the limit void ratio of coral sand is affected by roundness and internal porosity together, and internal porosity has a significantly greater impact than roundness. (5) Coral sand also largely follows the linear relationship between maximum void ratio and minimum void ratio which is based on terrigenous cohesionless soil.