微生物诱导矿化加固粉土坡面的径流与侵蚀特性

微生物诱导碳酸盐沉淀（MICP）是一种微生物矿化过程，能够胶结松散土体。将其应用于加固土体坡面提高抗降雨侵蚀能力具有潜在的发展前景。通过模拟降雨冲刷试验，对微生物诱导矿化加固前后粉土坡面的径流水动力与侵蚀特性开展研究，分析和讨论了水动力参数之间的相关性以及对土壤剥蚀率的影响规律。结果显示，加固后与加固前相比，粉土坡面径流的弗劳德数平均下降50%；在降雨前期的阻力系数平均下降66%，径流稳定后二者阻力系数接近；径流剪切力平均提高52%。径流系数与坡面入渗速率呈线性负相关（R²=0.857），与加固层的贯入强度呈指数负相关（R²=0.824）；入渗速率与加固层的贯入强度呈二次负相关R²=0.930）；径流剪切力与坡度呈指数正相关（R²=0.964）。加固粉土坡面的剥蚀率与加固层的贯入强度呈指数负相关（R²=0.822），与径流剪切力线性正相关（R2=0.912），临界径流剪切力为0.5 Pa。对于坡度10~25°的粉土坡面，微生物加固能将其剥蚀率从58.2~118.4 g/m2s降至2.4~21.2 g/m2s，剥蚀率最大降幅可达95.0%。粉土坡面经微生物诱导矿化加固后，水动力参数值发生显著变化，径流特性与水动力参数、加固层特性及坡度相关，坡面的抗冲刷侵蚀性能得到有效提升。

Properties of Runoff and Erosion on Silt Slope Surface Reinforced byMicrobial Induced Mineralization

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 siltslope was negatively correlated with penetration strength of the reinforced crust on slope (R²=0.822), linearly correlated withrunoff shear stress (R²=0.912). The critical runoff shear stress of reinforced silt slope was 0.5Pa. For silt slopes with a gradient of10-25°, the detachment rate could be reduced from 58.2-118.4 g/(m2s) to 2.4-21.2 g/(m2s) by microbial reinforcement, and themaximum detachment rate could be reduced by 95.0%. The hydrodynamic parameters of silt slope were significantly changed dueto the microbial-induced mineralization reinforcement. Furthermore, the runoff characteristics were related to the hydrodynamicparameters, the reinforced crust properties and slope gradient. The microbial-induced mineralization reinforcement effectivelyimproved the anti-erosion performance of the silt slope.