Engineering construction in loess areas often requires improvement of loess. Basalt fiber-reinforced soil due to complexity of material composition often exhibits poorly predictable mechanical behavior. In this study, digital image technology-based unconsolidated-undrained (UU) triaxial shear tests were carried out on loess samples at three fiber lengths (L) and four fiber contents (η). Results prove the improvement of the shear strength of loess by basalt fiber inclusion, which varies in inverted u-shaped pattern with fiber length or fiber content, with the maximum at η = 0.6%, L = 12 mm. Digital Image Technology was employed to analyze the damage characteristics and strain field of the surface of the sample at different loading time. The volumetric strain of the reinforced sample decreases at higher fiber content or fiber length, from shear contraction to dilatancy. The unreinforced sample exhibits a typical brittle failure mode with visible shear band, while plastic failure for reinforced samples with an overall bulging failure mode. A statistical damage constitutive model of fiber-reinforced loess was established with limited parameters calibrated. The rationality of the model was verified by comparisons of measured and calculated stress-strain data.

黄土地区的工程建设往往需要对黄土进行改良。由于材料成分的复杂性，玄武岩纤维增强土壤通常表现出难以预测的机械行为。在这项研究中，基于数字图像技术的不固结不排水 (UU) 三轴剪切试验在三种纤维长度 ( L ) 和四种纤维含量 ( η ) 的黄土样品上进行。结果证明玄武岩纤维包裹体对黄土抗剪强度的提高，随纤维长度或纤维含量呈倒U型变化，在η =0.6%时达到最大值，L= 12 毫米。采用数字图像技术分析不同加载时间下试样表面的损伤特性和应变场。增强样品的体积应变随着纤维含量或纤维长度的增加而降低，从剪切收缩到膨胀。未增强样品表现出典型的脆性破坏模式，具有可见的剪切带，而增强样品的塑性破坏则具有整体膨胀破坏模式。建立了有限参数标定的纤维增强黄土统计损伤本构模型。通过实测和计算应力-应变数据的对比验证了模型的合理性。