Development and Evaluation of a Sand Pluviator

An Approach to Standardized Sample Preparation for Physical Modelling in Geotechnics

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Abstract

For preparing standardized sand specimens for physical modelling in geotechnics, especially for the geo-centrifuge tests, a “line-style” sand pluviator has been recently developed by TU Delft. Controlling the falling height of sand hopper, the width of hopper’s bottom gap and the relative moving speed between the hopper and the sample box, specimens with bulk relative density ranging from 50% to 100% can be prepared by this automated machine using the coarse Merwede River sand. Besides, the periodic variation of local relative density along depth was observed using the macro-CT scanner and the features of the fabrics were investigated using the micro-CT scanner. It was also proved by a set of shallow foundation modelling tests that the sand specimens having the same bulk relative density but different heterogeneity and fabric features behaved significantly differently and further research works are recommended to explore the influences of these differences. Additionally, a partially substantiated hypothesis was proposed to conclude the general rules of the sand pluviation process, and the reliability of this hypothesis has been proved by a series of tests on the Geba sand.