Empirical Relationships for Grain Size Parameters of Calcareous Sand on Oahu, Hawaii


  • David A. Smith
  • Kwok Fai Cheung


Bioclastic sediments, equivalent diameter, calcareous sand, nominal diameter, shape factor, settling analysis, sieve analysis, sieve size


This paper provides quantitative comparisons and relationships for the grain size parameters obtained from 11 medium to very coarse calcareous sand samples collected on Oahu, Hawaii. Sieve and settling techniques separate each sample into groups by sieve size and fall velocity, respectively. Individual grain properties such as shape, fall velocity, intermediate dimension, nominal diameter, and equivalent diameter are presented. The distributions of the nominal and equivalent diameters within the sieve and settling groups are analyzed to provide the respective median diameters for the samples. The wide range of particle shapes in the sand explains the scatter of size parameters within each group obtained from sieve analysis. Settling technique, which separates grains by their hydraulic characteristics, precisely defines the median equivalent diameter for calcareous sand. Correlation of the results provides empirical relationships between the nominal and equivalent diameters of the individual grains as well as the median sieve size of the sand samples and the corresponding nominal and equivalent diameters. The proposed empirical relationships allow the more representative grain size parameters of calcareous sand to be determined directly from the commonly used sieve analysis.