程瑶佳, 唐朝生, 谢约翰, 等. 2021.微生物诱导碳酸钙沉积技术改性黄土结构强度试验研究[J].工程地质学报, 29(1): 44-51. doi: 10.13544/j.cnki.jeg.2020-359.
    引用本文: 程瑶佳, 唐朝生, 谢约翰, 等. 2021.微生物诱导碳酸钙沉积技术改性黄土结构强度试验研究[J].工程地质学报, 29(1): 44-51. doi: 10.13544/j.cnki.jeg.2020-359.
    Cheng Yaojia, Tang Chaosheng, Xie Yuehan, et al. 2021. Experimental study on structure strength of loess improved by microbial induced calcite precipitation [J]. Journal of Engineering Geology, 29(1): 44-51. doi: 10.13544/j.cnki.jeg.2020-359.
    Citation: Cheng Yaojia, Tang Chaosheng, Xie Yuehan, et al. 2021. Experimental study on structure strength of loess improved by microbial induced calcite precipitation [J]. Journal of Engineering Geology, 29(1): 44-51. doi: 10.13544/j.cnki.jeg.2020-359.

    微生物诱导碳酸钙沉积技术改性黄土结构强度试验研究

    EXPERIMENTAL STUDY ON STRUCTURE STRENGTH OF LOESS IMPROVED BY MICROBIAL INDUCED CALCITE PRECIPITATION

    • 摘要: 我国黄土地区的水土流失和地质灾害问题异常严重,这主要与黄土较差的工程地质性质有关。提出采用微生物诱导碳酸钙沉积(MICP)技术对黄土进行改性处理,以改善其力学性质。采用喷洒法的方式将制备好的微生物菌液和胶结液依次喷洒在土样表面进行MICP处理,基于贯入试验和碳酸钙含量测定试验,分析不同MICP胶结轮次(3次、5次、7次)和胶结液浓度(0.5 M、1 M、1.5 M)对MICP胶结土样结构强度和碳酸钙含量的影响。结果表明:(1)MICP技术能显著提高黄土的结构强度,并在黄土表面形成一层高强度的硬化壳;(2)随着胶结轮次增加,土体的硬化壳强度和厚度、内部强度逐渐增大,碳酸钙含量也随之增高;(3)胶结液浓度对MICP改性效果影响显著,1.0 M胶结液浓度的处理效果最好,其表层结构强度最高可达600 kPa,内部完整性好,1.5 M的次之,仅在表面形成较薄的硬化壳,内部强度低,0.5 M胶结液浓度处理的土体力学性质改良不明显;(4)MICP改善黄土结构强度的作用机理主要是微生物诱导生成的碳酸钙胶结土颗粒,极大提升土颗粒之间的联接强度,从而显著改善土体的力学特性。

       

      Abstract: Soil erosion and geological disasters in loess area of China are extremely serious, which is mainly related to the poor engineering geological properties of loess. Microbial induced calcium carbonate precipitation(MICP)was used in order to improve the mechanical behavior of loess. We sprayed the prepared bacterial solution and cementation solution to the surface of the soil sample for MICP treatment. Based on the penetration test and calcium carbonate content test, we analysed the influence of MICP-treated cycles(3, 5, 7 rounds) and cementation solution concentrations(0.5 M, 1 M, 5 M)on penetration strength and calcium carbonate content of MICP-treated samples. The results show that: (1)MICP technology can significantly improve the structure strength and form a hard crust with high strength on the surface of soil sample. (2)With the increase of MICP treatment cycles, the strength and thickness of hard crust, internal strength of soil and the content of calcium carbonate increase gradually. (3)The concentration of cementing solution has a significant influence. The sample treated by 1.5 M cementing solution performs the best treatment effect with structure strength of surface up to 600 kPa and good internal integrity. The effect of the sample treated by 1.5 M cementing solution is worse than 1.0 M. A thin hard crust is formed on the surface of it and the internal strength of it is low. The mechanical strength of soil sample treated by 0.5 M cementing solution is improved insignificantly. (4)The mechanism of MICP improvement on the structure strength of loess is mainly that calcium carbonate induced by microorganisms cements soil particles, which greatly improves the connection strength between soil particles and significantly improves the mechanical properties of soil.

       

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