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    肖海, 徐萌苒, 夏振尧, 朱志恩, 向瑞, 高峰, 张伦. 基于EICP原理强化掺磷石膏土壤的加固性能[J]. 应用基础与工程科学学报, 2024, 32(5): 1307-1318. DOI: 10.16058/j.issn.1005-0930.2024.05.008
    引用本文: 肖海, 徐萌苒, 夏振尧, 朱志恩, 向瑞, 高峰, 张伦. 基于EICP原理强化掺磷石膏土壤的加固性能[J]. 应用基础与工程科学学报, 2024, 32(5): 1307-1318. DOI: 10.16058/j.issn.1005-0930.2024.05.008
    XIAO Hai, XU Mengran, XIA Zhenyao, ZHU Zhien, XIANG Rui, GAO Feng, ZHANG Lun. Enhancement Performance for Reinforcement Property of the Soil Treated by Phosphogypsum Based on the EICP Principle[J]. Journal of Basic Science and Engineering, 2024, 32(5): 1307-1318. DOI: 10.16058/j.issn.1005-0930.2024.05.008
    Citation: XIAO Hai, XU Mengran, XIA Zhenyao, ZHU Zhien, XIANG Rui, GAO Feng, ZHANG Lun. Enhancement Performance for Reinforcement Property of the Soil Treated by Phosphogypsum Based on the EICP Principle[J]. Journal of Basic Science and Engineering, 2024, 32(5): 1307-1318. DOI: 10.16058/j.issn.1005-0930.2024.05.008

    基于EICP原理强化掺磷石膏土壤的加固性能

    Enhancement Performance for Reinforcement Property of the Soil Treated by Phosphogypsum Based on the EICP Principle

    • 摘要: 脲酶诱导碳酸钙沉淀技术(Enzyme Induced Carbonate Precipitation,EICP)是一种新型环保生物加固土体技术,磷石膏是一种可用于土壤加固的工业固体废弃物,而单加磷石膏土壤的加固效果有限,可以利用EICP技术对掺磷石膏土壤进行处理.设置7种磷石膏掺量(磷石膏占土壤的质量百分比为0、2%、4%、8%、16%、32%和64%)和5种尿素浓度(0mol/L、0.5mol/L、1.0mol/L、1.5mol/L和2.0mol/L),通过分析试样无侧限抗压强度、应力-应变曲线、破坏形态等来明确EICP反应对掺磷石膏土壤的加固性能的影响,并利用扫描电镜揭示其微观强化机制.研究结果表明:单加磷石膏时各试样的无侧限抗压强度为48.8~86.58kPa,而经EICP反应后,尿素浓度为0.5、1.0、1.5和2.0mol/L时试样无侧限抗压强度分别为77.94~94.86kPa、86.39~123.86kPa、114.58~134.34kPa和91.11~117.11kPa,抗压强度提升了21.83%~110.00%.此外,试样无侧限抗压强度增长量与碳酸钙生成量呈显著的指数关系(P<0.05),表明碳酸钙胶结作用是试样抗压强度增大的主要因素.微观分析表明,EICP反应过程中可利用磷石膏中的Ca2+,在试样中生成颗粒状及球状CaCO3,包裹-填充-胶结土壤颗粒,从而提高土体强度.以期该研究结果为磷石膏资源化综合利用提供理论依据,并对磷化工产业可持续发展及保护土地资源具有现实意义.

       

      Abstract: Enzyme Induced Carbonate Precipitation (EICP) is a new environment-friendly biological soil reinforcement technology.Phosphogypsum,an industrial solid waste,can also be utilized for soil reinforcement.However,the single reinforcement effect of phosphogypsum on soil is restricted,thus further research could be conducted to strengthen soil treated with phosphogypsum based on the EICP principle.Therefore,7 phosphogypsum contents (0,2%,4%,8%,16%,32% and 64%,mass percentage of the soil) and 5 urea concentrations (0,0.5,1.0,1.5 and 2.0mol/L) were established,and the reinforcement effect of EICP on the phosphogypsum-treated soil was evaluated through analyzing the unconfined compressive strength,stress-strain curves,calcium carbonate content,and damage morphology.Additionally,the microscopic reinforcement mechanism was revealed through the use of scanning electron microscopy.The results indicated that the unconfined compressive strengths of phosphogypsum-treated soil ranged from 48.8~86.58kPa,77.94~94.86kPa,86.39~123.86kPa,114.58~134.34kPa and 91.11~117.11kPa under the urea concentrations of 0,0.5,1.0,1.5 and 2.0mol/L,respectively.The EICP increased the unconfined compressive strengths by 21.83%~110.00% compared to the single phosphogypsum-treated soil.Furthermore,the increase in unconfined compressive strength demonstrated a significantly exponential relationship with the calcium carbonate content induced by EICP (P<0.05).This suggests that the cementation effect of the calcium carbonate is the primary factor contributing to the rise in unconfined compressive strength.Moreover,the EICP can generate granular and spherical CaCO3 that can encapsulate,fill or bond the soil particles,thereby enhancing the soil unconfined compressive strength.These findings can serve as a theoretical foundation for the comprehensive utilization of phosphogypsum resources.

       

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