降雨侵蚀严重威胁土质边坡稳定，甚至诱发失稳破坏。本研究联合黄麻纤维与微生物诱导碳酸钙沉淀(MICP)技术开展黄土坡面生态加固，模拟降雨测试分析坡面抗侵蚀性能提升程度及影响因素，利用扫描电子显微镜(SEM)和能量色散 X 射线光谱仪(EDS)从微观角度分析减缓黄土坡面降雨侵蚀作用机制，探究减缓黄土坡面降雨侵蚀的可行手段。结果表明：(1) 添加黄麻纤维有助提升微生物矿化黄土抗降雨侵蚀性能，尤以中高含量中长尺寸纤维的提升效果最佳。(2) 经生物矿化处理的纤维加筋黄土可显著抵抗弱降雨(6mm/h)侵蚀，亦能短期抵抗强降雨(45mm/h)侵蚀；强降雨条件下，抗侵蚀性能随纤维掺量增加而提升、但提升幅度逐步降低，最高抗侵蚀性能提升为 64.2％。(3) 生物胶结硬壳层厚度随纤维长度和含量的增加而变薄，C2L5 和 C8L25 之间厚度差能达到 2.86 倍。(4) 纤维加筋微生物矿化黄土表层存在两种胶结模式：1）碳酸钙晶体沉淀于粒间孔隙而成的“粒间填充”模式；2）碳酸钙借助纤维连接包裹土颗粒而成的“裹覆胶结”模式。研究结果对黄土丘陵沟壑区坡面降雨侵蚀防控措施的有效实施具有指导意义。

Rainfall erosion seriously threatens the stability of soil slopes and even induces instability and failure. In this study, jute fiber and microbial induced calcium carbonate precipitation (MICP) technology were combined to carry out ecological reinforcement of loess slope. Simulated rainfall test was used to analyze the improvement degree and influencing factors of slope erosion resistance. Scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS) were used to analyze the mechanism of mitigating rainfall erosion on loess slope from a micro perspective, and to explore the feasible means of mitigating rainfall erosion on loess slope. The results show that: (1) The addition of jute fiber can help to improve the rainfall erosion resistance of microbial mineralized loess, especially the medium and high content of medium and long size fiber. (2) The fiber reinforced loess treated by biomineralization can significantly resist the erosion of weak rainfall (6mm/h) and short-term erosion heavy rainfall (45mm/h). Under heavy rainfall conditions, the corrosion resistance increases with the increase of fiber content, but the increase range gradually decreased, and the highest corrosion resistance increased to 64.2%.(3) With the increase of fiber length and fiber content, the thickness difference between C2L5 and C8L25can reach 2.86 times.(4) There are two cementation modes in the surface layer of fiber-reinforced microbial mineralized loess: 1) the “intergranular filling” mode formed by the precipitation of calcium carbonate crystals in intergranular pores; 2) The “wrapped cementation” mode of calcium carbonate is formed by wrapping soil particles with fiber connection. The research results have practical guiding significance for the effective implementation of slope rainfall erosion prevention and control measures in the loess hilly and gully region.

TU528

四川省自然科学基金(No. 2022NSFSC0183)；四川省矿产资源研究中心科研项目(No. SCKCZY2022-YB012)；国家级大学生创新创业训练计划(项目编号202310615010;202310615015;202310615017)