关键词: 钙质砂, 级配, 颗粒形状, 球度, 圆度, 渗透性

Abstract: Calcareous sand is widespread in tropical marine regions (including the South China Sea). It is one type of special geomaterial with unique hydro-physical properties different from terrigenous sands. Through the conventional constant head permeability tests, the effect of particle size distribution with varied uniformity coefficients and curvature coefficients on the permeability of the calcareous sand has been investigated. In light of the unique shape of calcareous sand particle, the ratio, , of sphericity to circularity X was introduced to quantitatively describe the particle shape based on the SEM images. To explore the effect of particle shape on the permeability of the calcareous sand, an investigation was performed by comparing with Fujian standard sands and glass beads with the same particle size distribution and relative compaction. The test results indicate that the permeability of the calcareous sand increases with the growth of uniformity coefficients and curvature coefficients, being consistent with the effect of particle size distribution on common sands. Compared to the other two kinds of granular materials, the particle shape of the calcareous sand has significantly structural and nonuniform properties, which can significantly reduce the permeability. The results of the present study will provide a guide for the designs of the island building and platform foundations.

Key words: calcareous sand, particle size distribution, particle shape, sphericity, circularity, permeability