纤维含量是影响加筋土的重要参数，现有研究中纤维含量的取值范围一般较小，对较大纤维含量加筋土的物理力学性能尚不清楚。因此，为了研究较大纤维含量对稻草纤维加筋土的影响，本文设置了10个纤维质量分数，采用直剪试验进行研究，探讨了不同纤维含量对加筋土强度特性的影响，并通过扫描电镜试验（Scanning Electron Microscope，SEM）和核磁共振测试（Nuclear Magnetic Resonance，NMR）对纤维加筋土的微观结构特征进行分析。结果表明：加入纤维可有效提高土体的抗剪强度。纤维加筋土的增强机理与纤维含量有关，较小的纤维含量对土体孔隙率影响不大，加筋土以土骨架为基础；当纤维含量较大时，孔隙率明显增长，加筋土的主体结构将由土骨架和纤维骨架组成。本文的研究成果可为纤维材料在地基处理和边坡防护等实际工程中的设计和施工提供参考。

Fiber content is an important parameter affecting reinforced soil. In existing research, the range of fiber content values is generally small, and the physical and mechanical properties of reinforced soil with higher fiber content are not well understood. Therefore, in order to study the impact of higher fiber content on rice straw fiber-reinforced soil, this paper sets up 10 fiber mass fractions and uses direct shear tests for research, exploring the effect of different fiber contents on the strength characteristics of reinforced soil. Additionally, scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) tests are used to analyze the microstructure features of fiber-reinforced soil. The results show that adding fibers can effectively improve the shear strength of the soil. The reinforcement mechanism of fiber-reinforced soil is related to fiber content. A small fiber content has little effect on the porosity of the soil, and the reinforced soil is based on the soil skeleton. When the fiber content is high, the porosity increases significantly, and the main structure of the reinforced soil will be composed of both the soil skeleton and the fiber skeleton.. The research results of this paper can provide a reference for the design and construction of fiber in practical engineering applications such as foundation treatment and slope protection.

国家自然科学基金面上项目(52278335)；福建省社会发展引导性(重点)项目(2021Y0004)；福建省自然资源厅科研项目(2022122105)；清电(厦门)能源服务有限公司项目(2021111904),