Abstract

In the current study, Microbial-Induced Carbonate Precipitation (MICP) is used for the improvement of silty sand to mitigate wind erosion by spray-treating the soil surface layer with bacterial cell solutions. Wind tunnel, soil pocket penetrometer, and Torvane shear tests were carried out on the biologically treated and untreated samples. The bacteria were sprayed at bacterial concentrations of 0.05, 0.1, and 0.5 g/m² and the samples were exposed to wind speeds of 20.57, 26.18, and 31.79 m/s. The results showed that the effect of wind speed was more pronounced in the untreated samples than the treated samples. A marked decrease in wind erosion potential was observed in the treated samples which was dependent on the bacterial concentration. An increase in the bacterial concentration from 0.05 to 0.5 g/m² and in the curing time from 2 to 28 days decreased the wind erosion of the treated samples. Pocket penetrometer values were primarily affected by curing time and were almost independent of the bacterial concentration. The pocket penetrometer values of the treated samples were generally less than 2 MPa, which indicates the possibility of root growth. The results of the Torvane shear tests indicate that bio-cementation through MICP also increased the shear strength development of loose sand deposits. Scanning electron microscopy images of the structure of the treated samples revealed that MICP bound the sand particles together through CaCO₃ crystal formation in the voids between the particles.

摘要

在目前的研究中，微生物诱导的碳酸盐沉淀 (MICP) 用于通过用细菌细胞溶液喷雾处理土壤表层来改善粉砂质以减轻风蚀。对生物处理过和未处理过的样品进行风洞、土袋式贯入仪和 Torvane 剪切试验。细菌以 0.05、0.1 和 0.5 g/m ^{2 的}细菌浓度喷洒，样品暴露在 20.57、26.18 和 31.79 m/s 的风速下。结果表明，风速对未处理样品的影响比处理样品更明显。在处理过的样品中观察到风蚀潜力的显着降低，这取决于细菌浓度。细菌浓度从 0.05 增加到 0.5 g/m²和在 2 到 28 天的固化时间内减少了处理样品的风蚀。袖珍针入度计值主要受固化时间影响，几乎与细菌浓度无关。处理后样品的袖珍针入度值一般小于2 MPa，表明有根系生长的可能性。Torvane 剪切试验的结果表明，通过 MICP 进行生物胶结还增加了松散砂沉积物的剪切强度发展。处理过的样品结构的扫描电子显微镜图像显示 MICP 通过颗粒之间空隙中的CaCO ₃晶体形成将砂颗粒结合在一起。