低pH环境EICP固化不同粒径盾构渣土强度特性分析

    Strength analysis of EICP-solidified shield muck with different particle sizes under low-pH conditions

    • 摘要: 高含水率、泡沫剂残余等因素使盾构渣土较难直接使用,如何提高盾构渣土固化效果至关重要。单相低pH注浆法具有延缓酶诱导碳酸钙沉淀(EICP)反应进程的特性,是该技术的关键优势。基于此,开展了低pH环境下盾构渣土EICP固化的强度测试,探讨了不同粒径范围、泡沫剂及加固次数时EICP固化渣土的碳酸钙含量、超声波速、渗透系数和单轴抗压强度,量化了上述因素对渣土固化效果的影响。结果表明:在相同加固次数条件下,当粒径范围在0.5~1mm和0.5~2mm时,在0.1%阴离子表面活性剂(AES)、0.1%非离子表面活性剂(APG)条件下固化试样的单轴抗压强度要高于在去离子水(DW)环境下固化试样的单轴抗压强度。当粒径范围在1~2mm时,在0.1%AES、0.1%APG环境下固化试样的单轴抗压强度要低于在DW环境下固化试样的单轴抗压强度。本研究对比了多因素对EICP渣土固化效果的影响,为低pH环境下EICP加固盾构渣土提供实践依据。

       

      Abstract: High water content and residual foaming agents make shield muck difficult to reuse directly, highlighting the importance of improving its solidification effect. The single-phase low pH grouting method possesses the characteristic of retarding the Enzyme-Induced Carbonate Precipitation (EICP) reaction process, constituting a key advantage of this technology. Based on this, strength tests were conducted on EICP-solidified shield muck under low-pH conditions. The study investigated the calcium carbonate content, ultrasonic wave velocity, permeability coefficient, and unconfined compressive strength of the solidified muck under different particle size ranges, foaming agent types, and numbers of solidification cycles. The influence of these factors on the solidification effect was quantified. The results showed that, under the same number of treatments, the unconfined compressive strength of samples with particle sizes in the ranges of 0.5~1 mm and 0.5~2 mm solidified with 0.1% anionic surfactant (AES), and 0.1% nonionic surfactant (APG) was higher than that of samples solidified in deionized water (DW). In contrast, for samples with particle sizes in the range of 1~2 mm, the strength under AES and APG conditions was lower than that under DW. This study compared the effects of multiple factors on the solidification effect of EICP in shield muck, providing practical insights for the application of EICP in shield muck stabilization under low pH conditions.

       

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