Homogeneity and mechanical behaviors of sands improved by a temperature-controlled one-phase MICP method
Homogeneity and mechanical behaviors of sands improved by a temperature-controlled one-phase MICP method
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DOI：
10.1007/s11440-020-01122-4
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发表时间：
2021-01
期刊：
影响因子：
5.7
通讯作者：
Yang Xiao;Yang Wang;Shun Wang;T. M. Evans;A. Stuedlein;Jian Chu;Changhao Zhao;Huanran Wu
中科院分区：
文献类型：
--
作者：
Yang Xiao;Yang Wang;Shun Wang;T. M. Evans;A. Stuedlein;Jian Chu;Changhao Zhao;Huanran Wu
微生物诱导碳酸盐沉淀（MICP）作为一种有前途的改善土壤性质的方法已得到积极研究。阻碍其广泛应用的一个紧迫问题是 CaCO3 分布的严重空间不均匀性。受细菌活性对温度敏感性的启发，提出了一种控温单相 MICP 方法，该方法包括两个主要步骤：（1）在低温下用胶结剂和细菌溶液的混合物对试件进行灌浆； (2)将样品暴露在室温下诱导CaCO3沉淀。一系列实验证明了该方法相对于普通两相 MICP 方法的优势。采用所提出的温控方法处理的样品呈现出较高的 CaCO3 含量，并且沿样品的高度分布大致均匀；由于均匀分布的 CaCO3 沉淀形成了有效的粘结网络，这些样本的强度得到了显着提高，并具有明显的膨胀性。 SEM图像表明，控温方法倾向于形成均匀分布在晶粒表面的小晶体，这可以更有效地增加晶粒的粗糙度和残余应力。
Microbially induced carbonate precipitation (MICP) has been actively investigated as a promising method to improve soil properties. A burning issue impeding its wide application is the severe spatial inhomogeneity of the CaCO3distribution. Inspiring by the temperature sensitivity of the bacteria activity, a temperature-controlled one-phase MICP method is proposed consisting of two major steps: (1) grouting the specimen with the mixture of cementation and bacteria solutions in a low temperature; (2) inducing CaCO3precipitation by exposing the specimen to room temperature. A series of experiments are conducted to demonstrate the advantages of the proposed method over the normal two-phase MICP method. Specimens treated with the proposed temperature-controlled method present higher CaCO3contents with a roughly uniform distribution along the height of the specimen; the strength of those specimens are substantially improved with apparent dilatancy due to the effective bond network formed by the homogeneously distributed CaCO3precipitation. SEM images indicate that the temperature-controlled method tends to form small crystals distributing uniformly on the grain surface, which may increase the roughness of the grain and the residual stress more effectively.