Microbial induced carbonate precipitation (MICP) technology mainly uses carbonates formed by microbial life activities and environmental reaction to repair rock and soil. This paper is to study the effect of this technology on improving the impermeability and strength of fractured rock. The repair tests on fractured sandstone were carried out by using Bacillus Pasteurii. Meanwhile

the repaired fractured sandstone was tested under unconfined compression

nuclear magnetic resonance and scanning electron microscope (SEM). The repair effect and mechanism of Bacillus Pasteurii on the fractured sandstone were analyzed. Research shows that Bacillus Pasteurii has good repair effect on fractured sandstone. The longer the repair time is

the better the repair effect of Bacillus Pasteurii is. After 42 days of repair

the porosity of fractured sandstone decreased by 36.41%

the impermeability increased by 94.62%

and the compressive strength increased by 30.52%. The reason for the better repair effect of Bacillus Pasteurii is that the calcium carbonate induced by Bacillus Pasteurii can cement the filler and the sample

and greatly reduce the porosity of the sample

and improve the homogeneity of its internal pore structure.