Effects of diatom content on rheological properties of marine diatomite

Abstract

Diatomites, or natural soils containing diatoms are found in the marine environment all over the world. Diatomites tend to have skeleton microstructures, resulting in unique rheological behaviors. In marine areas, the rheological behavior of diatomite significantly contributes to geohazards, especially submarine landslides. Predicting and preventing submarine landslides require a profound understanding of the rheological characteristics of diatomites. Therefore, to assess the rheological characteristics of diatomite with different diatom and water contents, we prepared different diatom–kaolin mixtures (diatom contents ranging from 0 to 100 % and water contents from 66.8 % to 640 %) and subjected them to rheological shearing tests. The Herschel–Bulkley model and the Cheng's model were used to analyze the critical rheological parameters (i.e., dynamic and static yield stresses) and the flow behaviors of the samples. The results show that kaolin mixed with 20 % diatoms exhibits the highest value in yield stress. Also, the addition of diatoms alters the microstructure of kaolin which may lead to static yield at low water content and shear thickening at high water content. This study offers valuable references regarding critical rheological parameters and flow regimes for simulating submarine landslides in regions covered by natural sediments containing diatoms.