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摘要: 工程中使用水泥石灰等材料加固淤泥质土，由于土中的腐植酸有机质会阻碍水泥胶凝物质的形成，影响加固土长期强度。利用生物酶加固能够有效减小受有机质影响，但加固的时效特征却并不清晰。为探究生物酶固化剂加固淤泥质土的物性指标随时间变化规律，选择两种生物酶加固剂（泰然酶、E3酶）作为研究对象，开展加固土样的不排水不固结三轴剪切试验、光学显微与电镜扫描结合的细观结构测试等进行试验分析，研究结果表明：掺入两类生物酶以及各自改良配方后，土试样抗剪强度相较原状土最低各自提升了316.2%与287.3%。细观结构上泰然酶改良土体形成了板片状的致密结构，通过提高原土体内摩擦角达到增加抗剪强度，E3酶改良土表面则形成不规整的类球状或团聚状结构，强化了颗粒间的黏结作用，提高黏聚力以达到加固的目的。同时生物酶的效能发挥在时间尺度上为非单调增长，从第7天开始生物酶加固土样强度相较空白对照组具有优势，到60天强度逐步接近空白对照组，其作用效果存在明显的强化期（7~60 d）和衰落期（60~90 d）。研究成果对生物酶加固淤泥质土的工程问题解决具有较好的应用价值和理论意义。Abstract: Cement and lime materials are always used to reinforce muddy soft soil in the project, but the long-term strength of the reinforcing soil is affected by the organic matter of humic acid in the soil which will hinder the formation of cement gelling substances. Using bio-enzyme reinforcement can effectively reduce the impact of organic matter, but the aging characteristics of reinforcement are not clear. In order to explore the change of physical property index of reinforced muddy soft soil with time. Two typical biological enzymes (Terra, E3) were selected as research object to carry out undrained unconsolidated triaxial shear test and microscopic structure test combined with optical microscopy and electron microscopy for reinforced soil samples, the results show that after adding two type of Bio-enzyme (TerraZyme and E3), the mucky soft soils’ shear strength improved 316.2% and 287.3% at least compared to undisturbed soil. The TarraZyme’ improved soil forms a compact plate structure at the micro level. And it increases the shear strength of soil by raising internal friction angle. The Irregular spherical structure or agglomerate structure was formed by the Bio-enzyme of E3.It strengthens the bonding between particles and increases the cohesion to accomplish the purpose of strengthening soil. And the Bio-enzyme had played a non-monotony increased role in the time domain. From the 7th day, the strength of the bio-enzyme-reinforced soil sample has an advantage over the blank control group. By 60 days, the intensity gradually approached the blank control group. There are obvious reinforcement stages(7~60 days)and decline periods (60~90 days) in its effect. The research results have good application value and theoretical significance for the engineering problem solving of biological enzyme-reinforced silty soft soil.
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Key words:
- Bio-enzyme /
- mucky soils /
- shear strength /
- time-effect /
- micro-structure
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