Influence of Single-Dose Biocement Treatment on the Hydraulic Conductivity of the Riverbank Sand

Abstract

Biocementation through Microbially Induced Calcite Precipitation (MICP) is proven for amending the geotechnical properties of soil without disturbing the innate soil structure due to the water like consistency of cementation solutions. This study emphasizes the effect of single dosing of bio-cementation on the hydraulic conductivity of the Brahmaputra sand by one of the prominent soil bacterium Bacillus megaterium (NCIM 5472). The bio-calcification potential of Bacillus megaterium (BM) is first evaluated by its ability to produce urease and calcium carbonate. This is followed by the application of the biocementing culture into sand columns via injecting the cementation solution. The changes in the microstructure and mineralogy of the treated specimen were also analyzed. The saturated hydraulic conductivity is evaluated as a measure of change in pore space of treated sand at two different relative densities of soil. The major findings of the present study are that the change in the pore space via precipitation is more evident in low-density soil and at higher concentrations of the cementation solutions.