State-of-the-Art Review of Utilization of Microbial-Induced Calcite Precipitation for Improving Moisture-Dependent Properties of Unsaturated Soils

Unsaturated soil is a form of natural whose pores are filled by air and water. Different from saturated soil, the microstructure unsaturated consists three phases, namely, solid phase (soil particle), vapor phase, liquid phase. Due to matric suction pores, hydraulic mechanical behaviors soils present significant dependence on moisture condition, which usually results in series unpredictable risks, including foundation settlement, landslide, dam collapse. Microbial-induced calcite precipitation (MICP) novel environmentally friendly technology that can improve water stability soft or expansive soils. This paper reviews microscopic mechanisms MICP its effect properties The process mainly affected concentration calcium ions urea, apart bacteria. moisture-dependent were comparatively analyzed through models influence factors experimental data among various It suggests variations resilient modulus permanent deformation strongly related extent applied Finally, problems application, environmental challenges, further research directions suggested.