Effect of Cementation on Calcium Carbonate Precipitation of Loose Sand Resulting from Microbial Treatment

Microbe-induced calcite precipitation is a sustainable improvement technique for sandy soil, which can alter the properties of sand via microbial activity. In this study, we investigated the loose-sand-consolidation eff ect by controlling the injection velocity, bacterial and cementingsolution concentrations, and hold times. The results demonstrate that, as the cyclic batch increases, the utilization rate of the bacterial fl uid increases and both the optical density(OD600) of the bacteria and urease activity decrease. Moreover, it was determined that a 3-h hold time for a 0.5 mol/L cementing solution with a cementing fl uid velocity of 2 mL/min has the greatest bonding eff ect. The fi nal strength of the loose sand with an increase in calcium carbonate content was further discussed.