Measurement of Shear Wave Velocity During Microbial Grouting Based on Bender Element Tests
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摘要: 微生物加固可液化砂土的效果,受注浆过程中细菌体积、传输速率、孔隙再分布等因素的影响。且在实际应用过程中因试件制备造成其内部质量、密度等差异,导致难以科学判断试样内部微生物的具体成矿效果,严重影响其现场应用。过往的微生物加固试验研究多为单元尺度,而砂柱尺度应用较少。因此,在砂柱(长度0.5 m)上,通过自行研制的多点弯曲元多通道实时剪切波速测量装置,在微生物注浆过程中进行多位点实时监测,分段表达试件中微生物的成矿效果,藉此系统研究试件内部微生物诱导碳酸钙沉淀(MICP)的实时成矿规律。Abstract: The improving effect of liquefiable sand strengthened by microbes was influenced by bacterial volumes and transfer rates of slurry in the grouting, redistribution of pores, and etc. Due to differences of internal qualities, densities and other factors caused by preparation for specimens in actual application, it was difficult to scientifically judge the mineralization effect in specimens, thereby, the application of the microbial induced carbonate precipitation (MICP) technique in sites was restricted. The existing experimental study on microbial induced carbonate precipitation was in unit scales, rarely in sand column scales. Therefore, multi-point and real-time monitoring was conducted on sand columns (in a length of 0.5 m) in the process of microbial grouting with the self-developed multi-point and multi-channel measurement device of bender elements for shear wave velocity, and the mineralization effect of microorganisms in specimens was expressed in stages. It was verified that the multi-point shear wave velocity measurement device could be explored the real-time MICP mineralization situation in specimens.
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Key words:
- MICP /
- sand column /
- shear wave velocity /
- bender element /
- multi-channel monitoring system
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[1] JAFARIL S H, LAJEVARDI S H. Influence of freeze-thaw cycles on strength and small strain shear modulus of fine-grained soils stabilized with nano-SiO2 and lime using bender element tests[J]. Bulletin of Engineering Geology and the Environment, 2022, 81(234): 1-12. [2] FERREIRA C, DIAZ-DURAN F, CASCANTE G. New approach to concurrent and measurements using bender elements[J]. Geotechnical Testing Journal, 2021, 44(6): 1801-1820. [3] CHENG Z, LEONG E C. Determination of damping ratios for soils using bender element tests[J]. Soil Dynamics and Earthquake Engineering, 2018, 111: 8-13. [4] IAMCHATURAPATR J, PIRIYAKUL K, et al. Characteristics of sandy soil treated using EICP-based urease enzymatic acceleration method and natural hemp fibers[J]. Case Studies in Construction Materials, 2022,16,e00871. [5] SHIRLEY D J, HAMPTON L D. Shear-wave measurement in laboratory sediments[J]. Journal of the Acoustical Society of America, 1978, 63(2):607-613. [6] SHIRLEY D J. An improved shear wave transducer[J]. Journal of the Acoustical Society of American, 1978, 63(5):1643-1645. [7] SANCHES-SALINERO I, ROESSET J M, STOKOE K H. Analytical studies of body wave propagation and attenuation[R]. Austin: University of Texas, 1986. [8] ARULNATHAN R, BOULANGER R W, RIEMER M F. Analysis of bender element tests[J]. Geotechnical Testing Journal, 1998, 21(2):120-131. [9] JOVICIC V, COOP M R, SIMIC M. Objective criteria for determining Gmax from bender element tests[J]. Geotechnique, 1996, 46(2):357-362. [10] VIGGANI G, ATKINSON J H. Interpretation of bender element tests[J]. Geotechnique,1995,45(1):149-154. [11] 姬美秀,陈云敏,黄博.弯曲元试验高精度测试土壤剪切波方法[J].岩土工程学报, 2003,25(6):732-736. [12] SANTAMARINA J C, KLEIN K A, FAM M A. Soils and waves[M]. New York: John Wiley & Sons, 2001. [13] DE FONSECA A V, FERREIRA C, FAHEY M. A framework interpreting bender element tests, combining time-domain and frequency-domain methods[J]. Geotechnical Testing Journal, 2009, 32(2):91-107. [14] VON HIPPEL A. Dielectrics and waves[M]. New York: John Wiley and Sons, 1954. [15] BIOT M A. The theory of propagation elastic waves in a fluid saturated porous solid(Ⅰ):low-frequency range[J]. Journal of the Acoustical Society of America, 1956, 28(2):168-178. [16] 陈龙珠. 饱和土中弹性波的传播速度及其应用[D].杭州:浙江大学,1987. [17] DEJONG J T, FRITZGES M B, NÜSSLEIN K. Microbial induced cementation to control sand response to undrained shear[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2006, 132(11): 1381-1392. [18] VAN PAASSEN L A, GHOSE R, VAN DER LINDEN T J M, et al. Quantifying biomediated ground improvement by ureolysis: large-scale biogrout experiment[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2010, 36(12): 1721-1728. [19] 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. [20] 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. [21] VAN PAASSEN L A, HARKES M P, VAN ZWIETEN G A, et al. Scale up of BioGrout: a biological ground reinforcement method[C]//HAMZA M, SHAHIEN M, EL-MOSSALLAMY Y.Proceedings of the 17th International Conference on Soil Mechanics and Geotechnical Engineering. Amsterdam: IOS Press:2328-2333.
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