Model Scale Application of Biomineralization Technique: Dynamic Cone Penetration Test and Calcite Content

The biomineralization technique is recently gathering consideration as a promising, environmentally sound method for bettering engineering behavior of granular media. The present research includes model scale application of the biomineralization method, generally popular as microbially induced calcite precipitation (MICP) to improve cohesionless soils. A novel bio-chemical-distribution setup was designed for the application purpose which includes a biotreatment tank of 1.35 m—length, 1.13 m—width, and 0.65 m—height. Slotted injection pipes were provided to uniformly distribute the bacterial and chemical solutions in the biotreatment tank. A 1210 kg of poorly graded sand was placed in the biotreatment tank and treated using a co-culture of Bacillus pasteurii and Bacillus sphaericus along with a chemical solution for 9 days. The biosparging concept was introduced through air pumps to maintain an aerobic environment in the soil during treatment. Untreated and biomineralized sand was tested for dynamic cone penetration test (DCPT) and calcite percent for identifying variation of the number of blows along with calcite percentage. Results showed that the dynamic cone penetration significantly increased in biomineralized soil due to the higher precipitation percent of calcite.