Influence of Consolidation Pressure on Stress-Deformation Responses of Bio-mediated Residual Soil in Malaysia

Abstract

ABSTRACT Microbial-induced calcite precipitation has recently emerged as an attractive sustainable ground improvement technique. In present study, the stress-deformation responses of a bio-mediated residual soil in Malaysia were investigated through undrained triaxial compression tests with different isotropic consolidation pressures. A practical and effective bio-mediation treatment method for residual soil was proposed. Bio-mediation increased the residual soil isotropic yield stress from 40 kPa to 100 kPa attributed to the greater inter-particle resistances contributed by calcite precipitation. The soil compression index was also reduced from 0.188 to 0.071. The bio-mediated residual soil showed a greater radial resistance than its untreated counterpart when subjected to an isotropic pressure. Under isotropic consolidation pressure below the yield stress, the shear strength of bio-mediated soil was governed predominantly by the calcite content. However, beyond the yield stress, the calcite bonds would diminish and only a slight increase of ultimate shear strength was observed attributed to calcite densification.