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朱锐, 邢玮, 郭万里, 黄英豪, 周峰, 王旭东. 微生物加固渠基粉土的冻融特性及微细观机理研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20231014
引用本文: 朱锐, 邢玮, 郭万里, 黄英豪, 周峰, 王旭东. 微生物加固渠基粉土的冻融特性及微细观机理研究[J]. 岩土工程学报. DOI: 10.11779/CJGE20231014
Study on Freeze-thaw Performance and Micro-mechanism of Canal Foundation Silt Treated by MICP[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20231014
Citation: Study on Freeze-thaw Performance and Micro-mechanism of Canal Foundation Silt Treated by MICP[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20231014

微生物加固渠基粉土的冻融特性及微细观机理研究

Study on Freeze-thaw Performance and Micro-mechanism of Canal Foundation Silt Treated by MICP

  • 摘要: 渠基土性能冻融劣化是我国季冻区渠道结构损坏的主要原因,渠基土加固是保障供水渠道安全运行的重要手段。结合微生物岩土加固技术,开展微生物加固渠基粉土系列宏微观室内试验,刻画不同胶结液浓度、养护龄期、冻融循环下加固渠基粉土的体变率、渗透系数、孔隙率等宏微观指标的发展规律及其定量联系。结果表明:在不同胶结液浓度、养护龄期下,微生物加固可使得渠基粉土的冻融体变量削减约70%、渗透系数至少降低一个数量级、抗压强度提升约220.17%、抗剪强度指标最高增长约65.50%;当胶结液浓度为1.00 mol/L、养护龄期为28 d时,冻融循环下渠基粉土的微生物加固效果最优。此外,微生物诱导生成的碳酸钙沉淀通过填充、胶结、包裹等系列方式重塑了渠基粉土的微细观结构,使其在冻融风化作用下仍然保持整体性和完整性,这是微生物加固渠基粉土在冻融环境下仍然展现出良好工程特性的主要原因。

     

    Abstract: Freeze-thaw deterioration characteristics of foundation soil is the main cause of canal slopes damages in seasonally frozen areas. Soil treatment is an important means to ensure the safe operation of canal. Based on microbially induced calcium carbonate precipitation (MICP) technique, a series of laboratory tests on treated silt with different concentrations, curing ages and freeze-thaw cycles are conducted. The macro and micro indicators of treated silt, such as volumetric rate, permeability coefficient and porosity, are described and its quantitative relationships are established. The results show that under different concentrations and curing ages, the treatment can reduce the freeze-thaw deformation by 70%, decrease the permeability coefficient by at least one order of magnitude, increase the compressive strength by 220.17%, and improve the shear strength index by 65.50%. As the concentration is 1.00 mol/L and the curing age is 28 days, the treatment effect of silt under freeze-thaw cycles is the most significant. In addition, the calcium carbonate precipitation induced by MICP reshapes the microstructure of silt through a series of processes such as filling, cementation, and encapsulation, which ensures the integrity of silt subjected to freeze-thaw cycles. It is also the main reason for the good engineering properties of treated silt in freeze-thaw environments.

     

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