عنوان مقاله [English]
Nowadays, new construction on weak soils has become inevitable owing to the growing worldwide scarcity of land. The weak soil deposits are commonly characterized by low strength and high compressibility. Cementation or grouting is an important soil improvement method. It significantly strengthens soil static and dynamic properties, although artificial cementation, such as Portland cement, has been used widely in engineering practice, it may have potentially adverse environmental effects (e.g., significant CO2 emissions) or it may have limited injection distance due to high viscosity. It is important to use modern soil improvement and environmentally friendly methods. Therefore, calcium carbonate is formed in the process of biological improvement by using microorganisms in the soil and during biochemical reactions. This sediment improves the soil's hydraulic and soil properties by attaching soil grains. In this regard, the results of this study showed that the effective parameters on compressive strength, shear strength and soil permeability of biological systems (biomass) are microorganism type, soil compatibility of microorganisms, distribution and stabilization of bacteria in soil, concentration of bacterial solution, concentration of cementation solution, pH, temperature and injection method.