砂土体微生物固结的微观及力学特性研究

发布时间：2018-11-20 17:33

【摘要】：渗漏和坡岸崩塌是水利工程中常见病害,直接威胁工程运行安全。通过对4种不同粒径砂柱进行生物固结试验表明,生物固结方法能快速大幅度降低多孔介质渗透性,粒径较大的砂柱内部具有良好的营养物质输送通道,渗透系数下降速率相对较高。剪切试验结果表明,经生物固结处理后砂柱的抗剪强度有了明显提升,但未发现强度变化与砂样粒径之间存在任何明显的内在联系。由此可见,砂样强度的提高与钙质沉积的个体差异有关,同时强度的提高不仅和钙质沉积量有关,也与砂粒之间的胶结形式相关。微观研究结果表明,小粒径砂柱与大粒径砂柱内部钙质沉积形式有着显著差异,相对小粒径砂柱而言,钙质沉积在大粒径砂柱表面的分布较为凌乱,并非均匀附着。EDS能谱仪分析结果表明,砂柱内部固结物质主要成分为碳酸钙,并附有少量其他杂质。
[Abstract]:Leakage and bank collapse are common diseases in water conservancy projects, which directly threaten the safety of engineering operation. The biological consolidation tests of four different sand columns show that the biological consolidation method can reduce the permeability of porous media rapidly and greatly, and the sand column with larger particle size has a good transport channel of nutrients. The decrease rate of permeability coefficient is relatively high. The shear test results show that the shear strength of the sand column has obviously increased after biological consolidation, but there is no obvious internal relation between the strength change and the sand sample particle size. Therefore, the increase of sand strength is related to the individual difference of calcium deposition, and the increase of strength is related not only to the amount of calcium deposit, but also to the cementation form between sand grains. The microcosmic results show that there are significant differences between the calcareous deposition patterns in the small diameter sand column and the large diameter sand column. Compared with the small diameter sand column, the distribution of the calcium deposit on the surface of the large diameter sand column is disorderly. The results of EDS energy spectrometer show that the main composition of the consolidation material in the sand column is calcium carbonate with a small amount of other impurities.
【作者单位】：南京水利科学研究院;江苏省疾病预防控制中心;
【分类号】：TV223;TV698.2

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