Improvement of Sand Soil with Bio-micropiles and Bio-grout Injection in Reinforced Soils

The production of Portland cement, one of the most used materials in the construction industry, has increased environmental pollution and global warming. Soil bio-improvement is an eco-friendly and renewable method that has recently received attention. Microbially induced carbonate precipitation (MICP) has been the most researched for bio-geotechnical issues. Sporosarcina pasteurii is a micro-organism that produces urease enzymes and was used for sand soil improvement in this study. Also, the type of grout and injection method were selected as variables. The result of the test showed that the use of bio-grout had a significant effect on increasing the bearing capacity of soil. Bio-micropiles increased the bearing capacity by more than 94%. This increase was 126% in the case of cement-grouted micropile. Also, the results of the tests showed that the bearing capacity of bio-improved soil and reinforced soil increased by 54% and 125%, respectively. This research showed that bio-micropile could be a suitable method to replace cement-grouted micropile.