Abstract: Microbial induced carbonate precipitation (MICP) is a microbial mineralization process which can be adopted to cement loose soil. It has a potential development prospect to improve the anti-rainfall erosion ability of soil slope. Through the simulated rainfall erosion test, the hydrodynamic and erosion characteristics of the silt slope surface before and after the microbialinduced mineralization reinforcement were investigated. The correlation between the hydrodynamic parameters and the influence on the soil erosion rate were analyzed and discussed. The results showed that the Froude number of silt slope runoff decreased by 50% on average after reinforcement compared with before reinforcement. Moreover, the resistance coefficient decreased by 66% on average in the early stage of rainfall, and was close to that after runoff was stabilized. The runoff shear stress was increased by 52% on average. There was a linear negative correlation between runoff coefficient and slope surface infiltration velocity (R²=0.857), and an exponential negative correlation between runoff coefficient and penetration strength of the crust on slope (R²=0.824). There was a quadratic negative correlation between infiltration rate and penetration strength of the crust on slope (R²=0.930). The runoff shear stress was positively correlated with the slope gradient (R²=0.964). The detachment rate of the reinforced silt

slope was negatively correlated with penetration strength of the reinforced crust on slope (R²=0.822), linearly correlated with
runoff shear stress (R²=0.912). The critical runoff shear stress of reinforced silt slope was 0.5Pa. For silt slopes with a gradient of
10-25°, the detachment rate could be reduced from 58.2-118.4 g/(m2s) to 2.4-21.2 g/(m2s) by microbial reinforcement, and the
maximum detachment rate could be reduced by 95.0%. The hydrodynamic parameters of silt slope were significantly changed due
to the microbial-induced mineralization reinforcement. Furthermore, the runoff characteristics were related to the hydrodynamic
parameters, the reinforced crust properties and slope gradient. The microbial-induced mineralization reinforcement effectively
improved the anti-erosion performance of the silt slope.

Key words: microbial reinforcement, silt, rainfall erosion, detachment rate, hydrodynamic parameter