Muskeg Soil Stabilization Using the Microbially Induced Calcite Precipitation Technique by the Urease Active Bioslurry Approach

Abstract

Muskeg soil is widespread in Canada. It covers around 15% of the Canadian landscape. Its problematic nature is attributed to its high compressibility and low shear strength when subjected to loads because of its high initial void ratio and water content. Therefore, in this study, microbially induced calcite precipitation (MICP), an emerging and potentially environmentally friendly technique for soil stabilization, is used for enhancing the compressibility and shear strength properties of muskeg soil. The urease active bioslurry approach is adopted in this study, which comprises the mechanical mixing of bioslurry with soil and the injection of cementation solutions in subsequent phases. Muskeg soil was collected from Bolivar Park, Surrey, British Columbia, Canada. Different bioslurry concentrations were tested for the compressibility properties to determine the optimum concentration. Afterward, the optimum concentration was used to check the effect of the bioslurry percentage by weight and the number of cementation solutions injected on the soil stiffness and strength. Microstructure analysis by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were conducted for untreated and treated samples to check the change in the soil microstructure due to stabilization. The results showed that the 0.4 mol/L bioslurry concentration demonstrated the best compressibility properties.