首页|生物炭联合微生物矿化技术改善软土力学性能试验研究

生物炭联合微生物矿化技术改善软土力学性能试验研究

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  • 国家科技期刊平台
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  • NSTL
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[目的]实现对软土地基的绿色加固对工程建设及生态环境具有重要意义。为此，采用微生物诱导碳酸钙沉积(MICP)技术和生物炭联合固化软土。[方法]首先确定了 MICP灌浆最优细菌浓度和胶结液浓度，在此基础上，研究了不同生物炭含量联合微生物矿化技术加固提升软土的抗剪强度参数。通过直剪试验，得到MICP联合生物炭固化软土的内摩擦角和黏聚力。基于扫描电子显微镜(SEM)测试、X射线衍射(XRD)和能谱试验(EDS)，获得了固化软土的微观结构、矿物成分及元素分布特征。[结果]结果表明:(1)MICP能够提升软土内摩擦角和黏聚力，在最优菌液浓度OD600=0。9，胶结液浓度为1。0 mol/L的条件下，养护28 d时，MICP固化软土的最大内摩擦角为11。3°，最大黏聚力为12。15 kPa;添加生物炭后，MICP固化软土内摩擦角和黏聚力得到显著提升，添加12％生物炭，养护28 d时，内摩擦角最大为20。8°，相应条件下的黏聚力最大值为16。61 kPa。养护周期28d内，试样内摩擦角和黏聚力提升速率在前14 d明显高于后14 d，表明微生物矿化技术主要在养护前期发挥作用。(2)微观测试表明，经MICP处理的软土中均可观察到碳酸钙，添加生物炭后在生物炭和软土界面处观察到大量碳酸钙晶体。(3)EDS测试结果表明，土颗粒表面有明显的钙、碳和氧元素分布。[结论]研究结果证实了生物炭协同MICP技术固化软土具有可行性，为滨海软土地层的绿色加固提供了新的思路。
Enhancement of shear strength of soft soil using MICP combined with biochar
[Objective]Reinforcing the soft soil foundations in an environmentally friendly way holds significant importance on engineering construction and ecological environment.Therefore,the microbially induced carbonate precipitation(MICP)com-bined with bio-char method was introduced to the soft soil.[Methods]The optimal concentration of bacterial solution and cemen-tation solution of MICP-treated soft soil were determined using direct shear test.The effect of bio-char mixing ratio and curing time on the shear strength of MICP-bio-char-treated soft soil were investigated.The scanning electron microscope(SEM),X-ray diffraction(XRD)and Energy Dispersive Spectrometer(EDS)test were employed to reveal the microstructures,mineral compo-sition and distribution characteristics of elements.[Results]The results showed that the optimal parameters for improving the strength of MICP-treated soft soil was 0.9 of OD600 and 1.0 mol/L of cementation solution concentration,on the 28th day.In this case,the maximum values of internal friction angel and cohesion were 11.3 degrees and 12.15 kPa,respectively.Furthermore,the cohesion and internal friction angle greatly increased with the increase of bio-char mixing ratio and curing time.The optimal values of internal friction angle and cohesion were obtained when the bio-char mixing ratio was 12％and curing time was 28 days,which were 20.8 degrees and 16.61 kPa,respectively.During 28 days of curing time,the growth rates were higher within 14 days than those of later 14 days.Additionally,a large amount of calcium carbonate was observed in the MICP-treated soft soil.The calcium carbonate precipitated on the interface between bio-char and soft soil was the source of strength improvement com-pared with bio-char treated soft soil.Analysis of EDS indicated that there was a significant distribution of calcium,carbon,and oxygen elements on the surface of the soil sample.[Conclusion]It was demonstrated that the feasibility of bio-char combined with MICP on solidifying the soft soil.Furthermore,the findings of this study provide a new perspective for environmentally friendly reinforcement of soft soil in coastal areas.

microbially induced carbonate precipitation(MICP)soft soilbiocharinternal friction anglecohesionmechani-cal property

崔秀丽、李佳禧、谢佳旻、林军、庞书孟

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郑州工业应用技术学院建筑工程学院,河南新郑 451100

中国电建集团华东勘测设计研究院有限公司,浙江杭州 311122

汕头职业技术学院建设生态学院,广东汕头 515078

汕头大学土木与环境工程系,广东汕头 515063

东莞理工学院生态环境与建筑工程学院,广东东莞 523808

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微生物诱导碳酸钙沉淀 软土 生物炭 内摩擦角 黏聚力 力学性能

广东省自然科学基金广东省普通高校青年创新人才类项目汕头职业技术学院科研课题项目国家重点研发计划

2021A15151106772022KQNCX237SZK2023Z012022YFC3202900

2024

10.13928/j.cnki.wrahe.2024.07.012

水利水电技术(中英文)
水利部发展研究中心

水利水电技术(中英文)

CSTPCD北大核心
影响因子：0.456
ISSN：1000-0860
年,卷(期)：2024.55(7)