Impact of Microbial Metabolic Products on the Cone Penetration and Liquefaction Resistance of Sand

Microbially mediated liquefaction mitigation of soil relies on multiple strategies, e.g., biomineralization, biofilm and EPS (Extracellular polymeric substances) production, and biogenic gas formation. In this research, the impact of microbial metabolic products produced in situ by an endemic species of soil bacteria Bacillus megaterium RB-05 isolated from a naturally cemented site on cone penetration resistance and liquefaction resistance has been investigated for two minimally sustained different metabolic pathways. Toward this, a series of miniature cone penetration tests and shake table tests were performed in the laboratory on loose sand specimens inoculated with the endemic soil bacteria and bacteria-free control specimens. Results obtained from both tests clearly indicate a significant enhancement of cone tip resistance and liquefaction resistance of loose saturated sand specimens due to the production of microbial metabolic products such as EPS and Calcite within the sand matrix.