Abstract:Microbial-induced calcite precipitation (MICP) has the prominent advantage of significant improving the shear strength of soil, while MICP sand also has the obvious shortcoming of brittle failure. A certain amount of fiber was added into MICP sand in order to improve the brittleness, and based on consolidated drained triaxial compression tests, the shear strength characteristics of fiber-reinforced bio-cemented sand was studied. And then, the effects of fiber content, fiber length and initial relative compactness of samples on the shear characteristics of fiber-reinforced bio-cemented sand were discussed. Finally, the corresponding mechanisms of strength enhancement and ductility improvement were also investigated through scanning electron microscope. The results show that during the process of MICP, calcium carbonate crystals deposited on the fiber surface effectively improve the roughness of fibers surface, while the mixture of calcium carbonate and sand provides anchorage to the fibers, enhancing the shear strength of MICP sand and improving the strain softening characteristic, and it is concluded that fiber has the potential to improve brittleness of MICP sand.