Effect of Microbial Strains Through Triaxial Test on Bio-Treated Granular Soil

Microbiologically induced calcium carbonate precipitation (MICP) is a sustainable and environmental protection technique for ground improvement. In this study, the bacteria had determined Bacillus pasteurii, and the sources have different paths. One of the microbial strains was purchased from the bioresource collection and research center (BCRC) of the food industry research and development institute  (FIRDI). The other microbial strains were collected from the sewage of Dihua sewage plant and then isolated and purified from the sewage sample. Calcium chloride had determined the calcium sources, grouted with a single-phase solution in the undrained specimen, and ensured that the specimen was completely infiltrated by bacterial solution. Curing time had determined at 7 and 14 days. The treated specimens were examined by the triaxial static consolidation drained test. Under effective confining pressure at 50,100, and 200 kPa, the results indicate that after 7 days of curing, the volume change of YU-SP was greater that of BCRC-SP. Nonetheless, a stable increase in peak strength was observed with increasing curing time in BCRC-SP treated specimens, revealing distinct mechanical behaviors attributed to variations in bacterial strain sources.