Strengthening of sand by calcite producing bacteria Lysinibacillus sp. DRG3 isolated from a naturally cemented site

Saswati Ghatak, Suvendu Manna, Debasis Roy

In the proceedings of: GeoRegina 2014: 67th Canadian Geotechnical Conference

Session: Engineering Geology and Rock Mechanics

ABSTRACT: A non-pathogenic soil-residing bacterial strain Lysinibacillus sp. DRG3 was isolated from naturally cemented tailings sand site in eastern India. DRG3 is capable of producing extracellular polymeric substances (EPS) and calcite through ureolytic or non-ureolytic pathways which is rare. The potential of DRG3 in strengthening sand by introducing calcite cementation through ureolytic and non ureolytic process has been investigated in this paper. No report of calcite-precipitating ability of DRG3 or soil strengthening using DRG3 as bio-calcifying agent was found in the literature. In the present study biomass of DRG3 was utilized by growing them in mineral salt media without or with added urea. Observed increases in drained shear strength and dilatancy of water pluviated sand samples, particularly loose, treated with DRG3 from static triaxial test results were found to correlate with the amounts of biogenic EPS and calcite.

RÉSUMÉ: Un non pathogènes du sol-résidant souche bactérienne Lysinibacillus sp. DRG3 a été isolée de naturellement cimenté sable résidus site en Inde orientale. DRG3 est capable de produire des extracellulaires substances polymériques (EPS) et calcite par ureolytic ou non ureolytic pathways ce qui est rare. Le potentiel de la DRG3 dans le renforcement de sable en introduisant calcite cémentation en caisse par ureolytic et non ureolytic processus a fait l'objet d'une enquête dans ce papier. Aucun rapport de calcite-précipitant capacité des DRG3 ou renforcement des sols utilisant DRG3 comme bio-agent de calcification a été trouvé dans la littérature. Dans la présente étude la biomasse de la DRG3 a été utilisé par leur culture en sels minéraux médias sans ou avec ajout d'urée. Ogoûtez augmente dans vidangée résistance au cisaillement et dilatancy d'eau sable pluviated échantillons, particulièrement lâche, traités avec le système DRG3 de sstatic test triaxial résultats trouvés pour mettre en corrélation avec les montants des EPS biogéniques et calcite.

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