Experimental study on shear strength and creep properties of loess modified by microbially induced calcium carbonate precipitation (MICP) under freeze-thaw cycles

IF 6.5 2区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Case Studies in Construction Materials Pub Date : 2024-12-16 DOI:10.1016/j.cscm.2024.e04119

Jiaming Liu , Zhanyuan Zhu , Junlin He , Fei Luo , Yuping Yang , Huawei Gu , Zhuoying Wang

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引用次数: 0

Abstract

Numerous loess relic sites with cultural and historical values exist in the seasonally frozen ground region of Northwest China. Freeze-thaw action is an essential factor in inducing cracking and collapse of loess relic sites, and the creep behavior of loess also affects its long-term stability. Microbially induced calcium carbonate precipitation (MICP) technology has a promising application in earthen ruin reinforcement due to its environmental friendliness and good compatibility. To evaluate the feasibility of MICP technology for reinforcing loess relic sites in the seasonally frozen ground, triaxial compression tests, triaxial creep tests, and SEM tests were conducted on MICP modified loess after 0, 1, 3, 7, and 9 freeze-thaw cycles. Then, the changing laws of shear strength and creep properties of samples in the freeze-thaw conditions were analyzed. The results show that the MICP technology can enhance the mechanical properties and frost resistance of loess. The shear strength, cohesion, and long-term strength of MICP modified loess are enhanced by 27.8 %, 109 %, and 29.8 %, respectively, under 100 kPa confining pressure, and their reduction is smaller than that of the untreated loess after 9 freeze-thaw cycles; the internal friction angle fluctuates within 1°. Finally, the reinforcement mechanism and freeze-thaw resistance mechanism of MICP technology were revealed. Microbially induced calcium carbonate can cement soil particles, fill interparticle pores, and inhibit the development of pores and cracks caused by freeze-thaw action. The results can provide a theoretical foundation and scientific basis for the long-term stability analysis of loess relic sites reinforced with MICP technology.

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冻融循环下微生物诱导碳酸钙沉淀（MICP）改性黄土的抗剪强度和蠕变特性试验研究

西北季节冻土区存在着大量具有历史文化价值的黄土遗址。冻融作用是诱发黄土遗址开裂和崩塌的重要因素，黄土的蠕变特性也影响其长期稳定性。微生物诱导碳酸钙沉淀（MICP）技术因其环境友好、相容性好，在土坯加固中具有广阔的应用前景。为评价MICP技术加固季节性冻土黄土遗址的可行性，对MICP改性黄土进行了0、1、3、7、9次冻融循环后的三轴压缩试验、三轴蠕变试验和扫描电镜试验。然后，分析了冻融条件下试样抗剪强度和蠕变特性的变化规律。结果表明，MICP技术可以提高黄土的力学性能和抗冻性。在100 kPa围压下，MICP改性黄土的抗剪强度、黏聚力和长期强度分别提高了27.8 %、109 %和29.8 %，且经过9次冻融循环后，其降低幅度小于未处理黄土；内摩擦角在1°内波动。最后，揭示了MICP技术的加固机理和抗冻融机理。微生物诱导的碳酸钙可以胶结土壤颗粒，填充颗粒间孔隙，抑制冻融作用引起的孔隙和裂缝的发育。研究结果可为MICP技术加固黄土遗址的长期稳定性分析提供理论依据和科学依据。

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来源期刊

Case Studies in Construction Materials Multiple-

CiteScore

7.60

自引率

19.40%

发文量

842

审稿时长

63 days

期刊介绍： Case Studies in Construction Materials provides a forum for the rapid publication of short, structured Case Studies on construction materials. In addition, the journal also publishes related Short Communications, Full length research article and Comprehensive review papers (by invitation). The journal will provide an essential compendium of case studies for practicing engineers, designers, researchers and other practitioners who are interested in all aspects construction materials. The journal will publish new and novel case studies, but will also provide a forum for the publication of high quality descriptions of classic construction material problems and solutions.