随着工业化进程的加快，Zn2?的污染问题日益严重，对生态系统和工程结构稳定性构成了重大威胁。为了应对这一挑战，本文研究了MICP（Microbially Induced Carbonate Precipitation）协同氧化镁技术对Zn2?污染红黏土的固化效果。采用无侧限抗压强度试验和直接剪切试验，探讨了在不同胶结液浓度、氧化镁掺量及Zn2+浓度下固化土的无侧限抗压强度及抗剪强度指标变化规律；通过离子赋存形态试验，并结合固化前后试样pH值变化情况，分析了MICP协同氧化镁技术对Zn2?的固化效果。结果表明：氧化镁的掺入显著提高了Zn2?污染红黏土的无侧限抗压强度和抗剪强度，当氧化镁掺量为5%时利用率最高。胶结液浓度为1.0 mol/L时，抗压强度和抗剪强度最高。固化试样的抗剪强度指标主要受氧化镁掺量影响。氧化镁的掺入通过提升pH值，促进了MICP过程中碳酸钙的沉淀，同时加速了Zn2?从弱酸提取态向可还原态、可氧化态和残渣态转化。因此，MICP协同氧化镁固化Zn2?污染红黏土具有广泛应用前景，可为污染场地地基处理提供指导。

As industrialization accelerates, the pollution problem of Zn2+ is becoming increasingly severe, posing a significant threat to the stability of ecosystems and engineering structures. To cope with this challenge, this paper studies the solidification effect of MICP (Microbially Induced Carbonate Precipitation) combined with magnesium oxide on Zn2+ contaminated red clay. The variation of unconfined compressive strength and shear strength index of solidified soil under different concentrations of cementation solution, magnesium oxide contents and Zn2+ concentrations was discussed by unconfined compressive strength test and direct shear test. The curing effect of MICP combined with magnesium oxide technology on Zn2+ was analyzed by ion occurrence form test and pH value change of samples before and after curing. The results show that the incorporation of magnesium oxide significantly improves the unconfined compressive strength and shear strength of Zn2+ contaminated red clay. When the content of magnesium oxide is 5%, the utilization rate is the highest. When the concentration of cementation solution is 1.0 mol/L, the unconfined compressive strength and shear strength are the highest. The shear strength index of solidified samples is mainly affected by the content of magnesium oxide. The incorporation of magnesium oxide facilitated calcium carbonate precipitation during MICP by elevating the pH value. This process accelerated the transformation of zinc ions from a weak acid-extractable state to reducible, oxidizable, and residual states. Therefore, the combined MICP and magnesium oxide solidification of Zn2+ contaminated red clay holds promising applications and can provide guidance for the remediation of polluted site foundations.

TU411.3

国家自然科学基金(42262030)；广西岩溶动力学重大科技创新基地开放课题（KDL＆Guangxi202303）；河南省科技研发计划联合基金（225200810005）；广西岩土力学与工程重点实验室开放课题（桂科岩2023-XT-02）