Shear Fracture of MICP Bonds Considering Particle Shape

Microbially induced calcium carbonate precipitation (MICP) is a biomediated technique for soil improvement by forming calcium carbonate bonds between particles. Particle-scale tests on MICP bonds considering the particle shape effect remain relatively limited, although extensive tests have been conducted at the element scale. In this paper, we carried out a series of particle-scale shear tests on MICP bonds between particles of different shape characteristics to investigate the influences of particle shape and reinforcement level on the shear responses of interparticle MICP bonds. We find that all the specimens exhibit adhesive failure. The particle shape effects may also be related to the interparticle interlocking and the rivet effect from calcium carbonate in the local fluctuations at interparticle contacts. The shear strength of interparticle MICP bonds can be expressed as a power function regarding the particle shape parameter or the MICP treatment level. This study could provide a substantial data foundation for numerical and constitutive modeling of MICP-treated soils, accounting for complex particle shapes.