Bernardo Caicedo

Diatomaceous soils, which are frequent in lacustrine or marine deposits, emerged as a singular type of materials showing unusual geotechnical properties characterized by high values of Atterberg limits, high natural water content, and high compressibility but complemented with high shear strength. The high liquid limit accompanied by high friction angles seems contradictory to the classical soil mechanics. However, several studies have shown that the unusual geotechnical properties of diatomaceous soils are related to the micromechanical features of the diatoms.

This investigation considers two diatoms species (Aulacoseira granulate and Centric Coscinodiscus) and identifies the effect of each type of diatom into the overall macroscopic behaviour of the soils. The study involves several tests of Atterberg limits as well as oedometric and triaxial tests on samples having different proportions of diatoms of the two different species. Results evidence that the shape of the diatom at the micro scale has observable trends in the macroscopic response of the soils.