A Investigation of Coral Reef Sand Permeability and Factors Influencing Road Reconstruction and Expansion

For road reconstruction and expansion, the application of coral reef sand is warranted to improve the permeability. The relationship between pore ratio, grade, max particle size, coarse–fine particle content, and permeability of coral reef sand blow-fill materials was examined with applied with an indoor normal head permeameter. The permeability of the same level of calcareous sand was examined at different pore ratios. This study investigates the effects of the inhomogeneity coefficient, curvature coefficient, maximum particle size, and coarse and fine particle content on coral reef sand permeability. According to the results, the permeability coefficient of coral reef sand blow-fill mixes decreases with increasing pore ratio. It increases with increasing inhomogeneity coefficient, curvature coefficient, maximum particle size, and coarse particle content. The coarse & fine material content in the specimen is closely related to permeability performance size. Through the analysis of the indoor test results, considering multiple factors, the model of coral reef sand permeability coefficient: k20 = 2.38 × 10–4 × e2·Cu·Cc·d210·D is proposed. The present study provides reef sand formation permeability assessment and hydrology & environmental geology data support for the expressway reconstruction and expansion of coral reefs.