Mechanical Properties and Engineering Applications of Special Soils—Dynamic Shear Modulus and Damping of MICP-Treated Calcareous Sand at Low Strains
Mechanical Properties and Engineering Applications of Special Soils—Dynamic Shear Modulus and Damping of MICP-Treated Calcareous Sand at Low Strains
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DOI：
10.3390/app122312175
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发表时间：
2022-11
期刊：
影响因子：
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通讯作者：
Xin-lei Zhang;Jun Guo;Yu-min Chen;Yichun Han;Ruibo Yi;Hongmei Gao;Lu Liu;Han-long Liu;Zhifu Shen
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作者：
Xin-lei Zhang;Jun Guo;Yu-min Chen;Yichun Han;Ruibo Yi;Hongmei Gao;Lu Liu;Han-long Liu;Zhifu Shen
钙质砂沉积物沿着热带和亚热带地区的海岸线分布广泛。微生物诱导方解石沉淀法（MICP）是一种提高土的刚度和强度的新方法。小应变剪切模量和阻尼比是预测土的动力特性的两个关键参数，但对它们的研究却知之甚少。本文通过共振柱试验研究了经MICP处理的钙质砂的动力特性，着重研究了处理时间和围压对刚度和阻尼特性的影响。分析了初始动剪切模量与无侧限抗压强度的关系。此外，提供了参考剪应变与处理时间或围压之间的经验关系。结果表明，与未处理的钙质砂相比，胶结钙质砂的归一化剪切模量G/G 0具有更高的应变敏感性，Hardin-Drnevich模型能够描述其衰减规律。有效围压σc影响低胶结度下MICP处理后钙质砂动剪切模量的退化特性，但其影响随处理时间的增加而减小。参考剪应变与围压之间存在线性关系。参考剪切应变与处理时间呈幂律关系。
Calcareous sand deposits are widespread along the shoreline in tropical and subtropical regions. Microbially induced calcite precipitation (MICP) treatment is a new method for improving the soil’s stiffness and strength. The small-strain shear modulus and damping ratio of MICP-treated calcareous sand, two critical parameters for predicting the dynamic behavior of soil, are little known. This study conducts a series of resonant column tests to investigate the dynamic characteristics of MICP-treated calcareous sand, emphasizing the influence of treatment duration and confining stress on the stiffness and damping characteristics. It analyzes the relationship between the initial dynamic shear modulus and unconfined compressive strength. In addition, empirical relationships between the reference shear strain and treatment duration or confining stress are provided. The results show that the normalized shear modulus G/G0 of MICP-cemented calcareous sand has a higher strain sensitivity than that of untreated sand, and the Hardin–Drnevich model can describe its attenuation pattern. The effective confining stress σc affects the degradation characteristics of the dynamic shear modulus of MICP-treated calcareous sand with a low cementation level; however, its impact decreases as the treatment duration increases. There is a linear relationship between the reference shear strain and confining stress. While the relationship between the reference shear stain and treatment duration is a power law.