Determining the grain size distribution according to DIN EN ISO 17892-4

Using a sieve analysis or a slurry analysis, the mass proportions of grain fractions in the soil are determined and presented as a grain distribution curve. The grain size distribution is a basis for classifying soil and estimating its soil mechanical properties, e.g. compactibility, frost sensitivity, water permeability, filter stability, injectability.

The grain size distribution is determined by sieve analysis for grain sizes of 63 to 0.063 mm, by sedimentation for grain diameters smaller than 0.125 mm or as a combined sieve and sedimentation analysis for mixed-grain soils. In sieve analysis, the dried sample is shaken through a set of sieves with graduated mesh sizes. The residues on the individual sieves are weighed, converted into a percentage of the total dry mass, and summed up as a grain line. In sedimentation analysis or slurry analysis, the grain sizes are determined by their different sinking speeds in water. The soil sample is stirred to form a suspension. The density of the suspension is measured at predefined time intervals with an areometer.