张瑾璇, 黄明, 刘子健. 2023. 南方湿热区新型产脲酶菌加固土体的效果研究[J]. 工程地质学报, 31(1): 113-123. doi: 10.13544/j.cnki.jeg.2020-388.
    引用本文: 张瑾璇, 黄明, 刘子健. 2023. 南方湿热区新型产脲酶菌加固土体的效果研究[J]. 工程地质学报, 31(1): 113-123. doi: 10.13544/j.cnki.jeg.2020-388.
    Zhang Jinxuan, Huang Ming, Liu Zijian. 2023. Study on mechanical properties of soil reinforced by novel urease producing bacteria in south moist hot areas[J]. Journal of Engineering Geology, 31(1): 113-123. doi: 10.13544/j.cnki.jeg.2020-388.
    Citation: Zhang Jinxuan, Huang Ming, Liu Zijian. 2023. Study on mechanical properties of soil reinforced by novel urease producing bacteria in south moist hot areas[J]. Journal of Engineering Geology, 31(1): 113-123. doi: 10.13544/j.cnki.jeg.2020-388.

    南方湿热区新型产脲酶菌加固土体的效果研究

    STUDY ON MECHANICAL PROPERTIES OF SOIL REINFORCED BY NOVEL UREASE PRODUCING BACTERIA IN SOUTH MOIST HOT AREAS

    • 摘要: MICP技术可以通过生成的碳酸钙将松散土颗粒胶结为具有一定强度的结石体,而碳酸钙的形貌、尺寸、晶型等均会直接影响到碳酸钙的自身性能及其在土体中的填充、胶结作用效果,继而影响固化土体的力学性能。在MICP加固不良土体相关研究的基础上,将从南方湿热地区土壤中分离得到的产脲酶细菌的突变株YB7应用至4种土的MICP室内灌浆试验,并结合扫描电子显微镜、能谱仪对比分析了各试样中碳酸钙的结晶现象,最后对突变菌YB7的灌浆试样开展直剪及单轴压缩试验,结合宏观力学特性与碳酸钙的细观生长特征分析,系统研究了该细菌加固土体的作用效应。结果表明:南方湿热区新型产脲酶菌加固不良土体具有可行性,但土体结构会对碳酸钙的生成情况造成影响,颗粒级配、矿物形貌适宜的土体中碳酸钙的生成效果更好,相应灌浆试样的胶结效果也更好。试样的力学性能受土的结构、碳酸钙的生长情况以及碳酸钙与土颗粒间的胶结效果共同影响。研究成果可为该技术的进一步推广应用提供研究基础。

       

      Abstract: MICP technology cements loose soil particles into a stone body with a certain strength through the induced calcium carbonate. The morphology, size and crystal type of calcium carbonate would affect its filling and cementing effect in the soil, and then affect the mechanical properties of the cemented soil. On the basis of the related research about the reinforcement of the adverse soil mass by MICP technology, we screened the urease-producing bacteria from the soil in the southern moist heat areas for ultraviolet mutagenesis treatment. Then we selected the bacteria after UV mutagenesis, and got the mutant strain YB7 with high urease production. After that, we applied the mutant strain YB7 to the MICP laboratory grouting test of four soil samples. Combined with scanning electron microscope and energy spectrometer, we compared and analyzed the crystallization phenomenon of calcium carbonate in each sample. Finally, we carried out the direct shear test and uniaxial compression test on the grouting samples of the mutant strain YB7. Combining macroscopic mechanical characteristics and mesoscopic growth characteristics analysis of calcium carbonate, we studied the effect of the mutant strain YB7 on soil reinforcement systematically. The results showed that the novel urease producing bacteria in the southern warm wet area are feasible to reinforce the poor soil, but the structure of the soil can affect the formation of calcium carbonate. The formation effect of calcium carbonate in the soil with suitable particle gradation and suitable mineral morphology is better, and the cementation effect of the corresponding grouting sample is also better. The structure of the soil, the growth of calcium carbonate, and the cementation effect between the calcium carbonate and the soil particles can affect the mechanical properties of the sample. The results can provide a research basis for the further promotion and application of this technology.

       

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