微生物生物聚合物和棕榈纤维稳定的砂-粘土混合物的崩解和侵蚀行为。

Cracking and erosion behaviors of sand-clay mixtures stabilized with microbial biopolymer and palm fiber.

机构信息

School of Earth Sciences and Engineering, Hohai University, Nanjing 210098, China.

出版信息

Sci Total Environ. 2023 Dec 20;905:166991. doi: 10.1016/j.scitotenv.2023.166991. Epub 2023 Sep 13.

DOI:10.1016/j.scitotenv.2023.166991

Abstract

Drying-induced cracks and precipitation-induced erosion negatively impact the performance of soils in the context of extreme weather events. This study introduces two effective and sustainable materials, microbial biopolymer (MB) and palm fibers (PF), for cracking and erosion control in the sand-clay mixtures. A series of desiccation cracking tests, erosion tests, and SEM tests were conducted to evaluate the effectiveness of the treatment. The results showed that MB could significantly improve the resistance of the soil to cracking and scouring, and the improvement increased with increasing MB content. The optimum MB content was 0.15 % to achieve the maximum cracking and erosion resistance. For samples with varying sand contents, 0.15 % MB addition reduced the crack ratio, total crack length, and accumulative erosion ratio by 19.55 %-96.91 %, 4.22 %-99.58 %, and 57.88 %-89.53 %, respectively. In addition, PF positively affected the anti-crack and anti-erosion properties of the soil, and the application of 0.60 % PF had the best performance for both improvements. The cracks in the soils were mostly fine and shallow with the addition of 0.60 % PF, and therefore, the accumulative erosion ratio decreased by 44.18 %-62.76 % for samples with varying sand contents. Compared to the untreated soil, the degree of cracking and erosion was less due to the formation of a structure with more macropores and a sand skeleton in the treated samples with higher sand content. MB addition provides strong inter-particle bonding connections and a hydrophilic crust structure to improve the soils' resistance to cracking and erosion, while the fiber reinforcement effect benefits from interfacial friction and spatial restriction effects. This study provides mechanistic interpretations of desiccation cracking and erosion behavior in sand-clay mixtures under different treatments. It may guide the design of low-carbon technologies for geotechnical engineering applications.

摘要

干燥诱导的裂缝和沉淀诱导的侵蚀会对极端天气条件下土壤的性能产生负面影响。本研究引入了两种有效且可持续的材料，微生物生物聚合物（MB）和棕榈纤维（PF），以控制砂-粘土混合物中的干裂和侵蚀。进行了一系列干燥开裂试验、侵蚀试验和 SEM 试验，以评估处理的效果。结果表明，MB 可以显著提高土壤的抗裂和抗冲蚀能力，且随着 MB 含量的增加而增加。最佳 MB 含量为 0.15%，以获得最大的抗裂和抗侵蚀能力。对于不同砂含量的样品，添加 0.15%MB 可将裂缝比例、总裂缝长度和累积侵蚀率分别降低 19.55%-96.91%、4.22%-99.58%和 57.88%-89.53%。此外，PF 对土壤的抗裂和抗侵蚀性能有积极影响，添加 0.60%PF 的效果最好。添加 0.60%PF 的土壤中的裂缝大多细小而浅，因此，不同砂含量样品的累积侵蚀率降低了 44.18%-62.76%。与未处理的土壤相比，由于处理后的高砂含量样品中形成了具有更多大孔和砂骨架的结构，因此裂缝和侵蚀程度较小。MB 增加了颗粒间的强结合连接和亲水壳层结构，从而提高了土壤的抗裂和抗侵蚀能力，而纤维增强效应则得益于界面摩擦和空间限制效应。本研究对不同处理下砂-粘土混合物的干燥开裂和侵蚀行为提供了机理解释。它可能为岩土工程应用中的低碳技术设计提供指导。