Soil reinforcement using randomly distributed fibres to improve the shear strength has been identified as an effective and environment-friendly technique in engineering applications. Loess used in geotechnical constructions can suffer from cracking due to shear failure. To increase loess shear strength, triaxial compression tests were carried out to evaluate the effect of randomly distributed fibre reinforcement on the mechanical response of loess soil to load. In the present investigation, five groups of loess specimens were prepared with three fibre contents (i.e., 0.5%, 0.75%, and 1% by weight of dry loess) and two different fibre lengths (i.e., 9 mm and 18 mm). The experimental results indicate that the addition of fibre to soil significantly improves the failure stress and shear strength parameters of the loess compared with unreinforced loess specimens. As fibre content increases up to 0.75%, the cohesion of reinforced soil is greatly improved, whereas the amount of increase of the internal friction angle is much less significant. However, the cohesion decreases with the fibre content exceeding 0.75%, as the excessive fibre content may influence the formation of homogeneous mixture, resulting in interfacial mechanical interactions between the fibre surface and soil to be impaired. Loess specimens reinforced with longer fibre exhibited a greater cohesion than those reinforced with shorter fibre, while the internal friction angle is nearly insensitive to the fibre length. As the fibre length increases from 9 to 18 mm, the cohesion increases by 23.2%. In addition, the macro-morphology of fibre-reinforced specimens after triaxial shear tests suggests that an appropriate choice of fibre has the potential to increase soil cracking resistance capacity.

中文翻译：

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随机分布的纤维对黄土三轴剪切特性的影响

在工程应用中，使用随机分布的纤维进行土壤加固以提高剪切强度已被认为是一种有效且环保的技术。用于岩土工程的黄土会因剪切破坏而开裂。为了提高黄土的抗剪强度，进行了三轴压缩试验，以评估随机分布的纤维增强对黄土对荷载的机械响应的影响。在本研究中，准备了五组黄土样品，它们具有三种纤维含量（即干黄土重量的0.5％，0.75％和1％）和两种不同的纤维长度（即9mm和18mm）。实验结果表明，与未增强的黄土样品相比，向土壤中添加纤维可显着改善黄土的破坏应力和抗剪强度参数。当纤维含量增加到0.75％时，加筋土的内聚力大大改善，而内摩擦角的增加幅度则不那么明显。然而，当纤维含量超过0.75％时，内聚力降低，因为过量的纤维含量可能会影响均匀混合物的形成，从而导致纤维表面与土壤之间的界面机械相互作用受到损害。用长纤维增强的黄土试样比用短纤维增强的黄土试样表现出更大的内聚力，而内摩擦角对纤维长度几乎不敏感。随着纤维长度从9毫米增加到18毫米，内聚力增加23.2％。另外，纤维增强的试样的后三轴剪切试验的宏观形貌表明，纤维的一个合适的选择具有增加土壤开裂性容量的潜力。