Mechanical and Fluid Flow Behavior of Granular Mixtures in Response to Intraporous Grain Contents

초록

The behavior of diatom mixtures is different from that of classical geomaterials because of their intraporous characteristics. This study aims to investigate the mechanical and fluid flow behaviors of sand-diatom mixtures; sand-diatom mixtures were prepared with various diatom contents DC = 0%, 2%, 5%, and 20%, and they were remolded (70 mm diameter and 140 mm height) for consolidated-drained triaxial tests. For fluid-flow behavior, the extracted hydraulic conductivity data were analyzed using a gravimetric-volumetric framework. The test results showed that dilatancy arises during shear when the confining stress and diatom content are low. Even 2% addition of a diatom significantly decreased the shear strength because of the softer diatom particles. For hydraulic conductivity, the extracted data and model capture the dramatic decrease at low diatom content although the model overestimates the hydraulic conductivity at diatom content DC > 30%. The overlapped functions indicate that 50% reduction takes place at diatom content DC approximate to 10% for shear strength and diatom content DC approximate to 2% hydraulic conductivity when the extracted data are normalized. Consequently, diatoms represented by the soft grain property and intraporous grain lead to distinct influences on the mechanical and fluid flow properties.

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