Microbial induced calcium carbonate precipitation is a new kind of environmental-friendly soil reinforcement technology. Through laboratory MICP grouting test of expansive soil modification using Sporosarcina pasteurii, we investigated into the influences of cementing fluid concentration on the mechanical properties, microstructure and hydraulic characteristics of expansive soil. Moreover, we also revealed the mechanism and effect of modifying expansive soil by MICP technology. Test results demonstrate that MICP is effective in modifying expansive soil. After grouting, the unconfined compressive strength of soil samples increased by 379.4% at most, and the stiffness of soil was also improved. The expansibility and permeability of the samples reduced by up to 25.3 kPa and by three orders of magnitude, respectively. The modification effect ameliorated with the increase of cement concentration; but when the cement concentration reached a certain extent, the modification effect was no longer significant. The research findings verified the effectiveness and feasibility of MICP technology in modifying expansive soil.
Key words
expansive soil /
MICP technology /
cementing fluid concentration /
grouting /
mechanical property /
microscopic characteristic /
hydraulic characteristic
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References
[1] WHIFFIN V S, VAN PAASSEN L A, HARKES M P. Microbial Carbonate Precipitation as a Soil Improvement Technique[J]. Geomicrobiology Journal,2007,24(5): 417-423.
[2] HARKES M P,VAN PAASSEN L A,BOOSTER J L,et al.Fixation and Distribution of Bacterial Activity in Sand to Induce Carbonate Precipitation for Ground Reinforcement[J].Ecological Engineering,2010,36(2):112-117.
[3] VAN PAASSEN L A, GHOSE R, VAN DER LINDEN T J M, et al. Quantifying Bio-mediated Ground Improvement by Ureolysis: A Large Scale Biogrout Experiment[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2010, 136: 1721-1728.
[4] SOON N W, LEE L M, TAN C K, et al. Improvements in Engineering Properties of Soils through Microbial-induced Calcite Precipitation[J]. KSCE Journal of Civil Engineering, 2013, 17(4): 718-728.
[5] 邵光辉,尤 婷,赵志峰,等.微生物注浆固化粉土的微观结构与作用机理[J].南京林业大学学报(自然科学版),2017,41(2):129-135.
[6] 彭 劼,温智力,刘志明,等.微生物诱导碳酸钙沉积加固有机质黏土的试验研究[J].岩土工程学报,2019,41(4):733-740.
[7] 沈泰宇,汪时机,薛 乐,等.微生物沉积碳酸钙固化砂质黏性紫色土试验研究[J].岩土力学,2019,40(8):3115-3124.
[8] GB/T 50123—2019,土工试验方法标准[S].北京:中国计划出版社,2019.
[9] 丁振洲,郑颖人,李利晟.膨胀力变化规律试验研究[J].岩土力学,2007,28(7):1328-1332.
[10] QABANY A A, SOGA K, SANTAMARINA C. Factors Affecting Efficiency of Microbially Induced Calcite Precipitation[J]. Journal of Geotechnical & Geoenvironmental Engineering, 2011, 138(8): 992-1001.
[11] HILL D D, SLEEP B E. Effects of Biofilm Growth on Flow and Transport through a Glass Parallel Plate Fracture[J]. Journal of Contaminant Hydrology, 2002, 56(3): 277-246.
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