Department of Civil Engineering, Payame Noor University, P.O. Box 19395-3697, Tehran, Iran.
Faculty of Engineering, Hamedan Branch, Islamic Azad University, Hamedan, Iran.
Environ Sci Pollut Res Int. 2023 Jul;30(31):77517-77534. doi: 10.1007/s11356-023-27512-1. Epub 2023 May 31.
This paper aims to investigate the effect of leachate on the geotechnical parameters and the cracking behavior of compacted clay liners (CCLs) containing different percentages of polypropylene fibers. Accordingly, 200 compacted clay samples were reinforced with different percentages of fiber contents (FC) (i.e., 0, 0.5, 0.75, and 1%) and prepared with water or leachate to conduct different laboratory tests. First, the physical properties of the clay were determined. Then, the shear strength parameters (i.e., cohesion and friction angle), unconfined compressive strength, and the hydraulic permeability were determined subjected to water or leachate. Notably, the cracking behavior was modeled using visual images of the samples. The leachate increased desiccation cracks in the natural soil from 0.425 to nearly 1.111%. However, the addition of 0.5% (in the case of water) and 1% (in the case of leachate) fiber to the soil reduced the surface desiccation cracks in clay liners to about 0.185 and 0.352%, respectively. In both water- or leachate-prepared samples, the addition of fibers significantly increased the cohesion and friction angle. The shear strengths of the unreinforced leachate-prepared samples were lower than those of the water-prepared samples. The shear strength and unconfined compressive strength of all specimens increased with increasing fiber percentage. The presence of fibers in all samples caused more ductile behavior. The required amount of energy to achieve the maximum strength in the samples increased with increasing FC. By increasing the percentage of fibers, the permeability of the natural soil and the leachate-prepared samples increased. However, the highest permeability was observed in the leachate-prepared samples containing 1% fibers of 8.3 × 10 m/s, which is less than 10 m/s (maximum allowable permeability for clay liners). Finally, the obtained results were satisfactorily confirmed by scanning electron microscopy (SEM) analysis.
本文旨在研究渗滤液对含有不同聚丙烯纤维含量（FC）的压实粘土衬垫（CCL）的土工参数和开裂行为的影响。因此，用不同百分比纤维含量（即 0、0.5、0.75 和 1%）增强了 200 个压实粘土样品，并用水或渗滤液制备以进行不同的实验室测试。首先，确定了粘土的物理性质。然后，在水或渗滤液作用下，测定了剪切强度参数（即凝聚力和内摩擦角）、无侧限抗压强度和水力渗透性。值得注意的是，使用样品的视觉图像对开裂行为进行了建模。渗滤液使原状土中的干燥裂缝从 0.425 增加到近 1.111%。然而，在土壤中添加 0.5%（水的情况下）和 1%（渗滤液的情况下）的纤维分别将粘土衬垫表面的干燥裂缝减少到约 0.185%和 0.352%。在水或渗滤液制备的样品中，添加纤维均显著提高了凝聚力和内摩擦角。未增强的渗滤液制备样品的抗剪强度低于水制备样品。所有样品的剪切强度和无侧限抗压强度均随纤维百分比的增加而增加。所有样品中的纤维均导致更韧性的行为。达到样品最大强度所需的能量随着 FC 的增加而增加。随着纤维百分比的增加，原状土和渗滤液制备样品的渗透性增加。然而，在含有 1%纤维的渗滤液制备样品中观察到最高的渗透率为 8.3×10^-5 m/s，小于 10^-5 m/s（粘土衬垫的最大允许渗透率）。最后，扫描电子显微镜（SEM）分析对获得的结果进行了满意的验证。
