Issue |
E3S Web of Conf.
Volume 382, 2023
8th International Conference on Unsaturated Soils (UNSAT 2023)
|
|
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Article Number | 14010 | |
Number of page(s) | 6 | |
Section | Hydro-Mechanical and Thermal Properties of Bentonites and Bentonite-Based Mixtures - Part I | |
DOI | https://doi.org/10.1051/e3sconf/202338214010 | |
Published online | 24 April 2023 |
Microstructure and hydro-mechanical behaviour of compacted granular bentonite
1 Universitat Politècnica de Catalunya (UPC), Barcelona, Spain
2 International Centre for Numerical Methods in Engineering (CIMNE), Barcelona, Spain
3 Italian Institute for Environmental Protection and Research (ISPRA), Rome, Italy
* Corresponding author: hao.zeng@upc.edu
In recent years, granular bentonite GB has become a reference material since it facilitates the backfilling operation due to high-density compacted granules with extended grain size distribution(maximum sizes around 10 mm). This investigation explores the initial microstructure of MX80-type GB and the hydro-mechanical HM response observed at the phenomenological scale. Samples were statically compacted at a fixed dry density (1.55 Mg/m3 ), encompassing dry and wet sides of the optimum. Themicrostructural study was performed using a combination of X-ray micro-computed tomography and mercury intrusion porosimetry. The results indicate that the pore size density function of compacted GB can be simplified as a double-porosity network with micropores (intra-granular/aggregate pores) and macropores(inter-granular/aggregate pores). Compacting at the dry side increases macropores, making the sample more compressible on loading under as-compacted states despite the higher matric suction. The time evolution of the swelling pressure displays a double-peak pattern attributed to the particular microstructure of the samples. Moreover, the initial microstructure does not significantly influence the water retention properties without a marked hysteresis in the high-suction range under confined wetting/drying cycles. This work’s outcomes highlight the microstructure’s significance in the HM behaviour of compacted GB and provide further insight into the geotechnical properties of this material.
© The Authors, published by EDP Sciences, 2023
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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