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学者姓名：崔明娟
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Abstract ：
Enzyme-induced carbonate precipitation(EICP)is an emanating,eco-friendly and potentially sound technique that has presented promise in various geotechnical applications.However,the durability and microscopic characteristics of EICP-treated specimens against the impact of drying-wetting(D-W)cycles is under-explored yet.This study investigates the evolution of mechanical behavior and pore charac-teristics of EICP-treated sea sand subjected to D-W cycles.The uniaxial compressive strength(UCS)tests,synchrotron radiation micro-computed tomography(micro-CT),and three-dimensional(3D)recon-struction of CT images were performed to study the multiscale evolution characteristics of EICP-reinforced sea sand under the effect of D-W cycles.The potential correlations between microstructure characteristics and macro-mechanical property deterioration were investigated using gray relational analysis(GRA).Results showed that the UCS of EICP-treated specimens decreases by 63.7％after 15 D-W cycles.The proportion of mesopores gradually decreases whereas the proportion of macropores in-creases due to the exfoliated calcium carbonate with increasing number of D-W cycles.The micro-structure in EICP-reinforced sea sand was gradually disintegrated,resulting in increasing pore size and development of pore shape from ellipsoidal to columnar and branched.The gray relational degree suggested that the weight loss rate and UCS deterioration were attributed to the development of branched pores with a size of 100-1000 μm under the action of D-W cycles.Overall,the results in this study provide a useful guidancee for the long-term stability and evolution characteristics of EICP-reinforced sea sand under D-W weathering conditions.
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| GB/T 7714 | Ming Huang , Kai Xu , Zijian Liu et al. Effect of drying-wetting cycles on pore characteristics and mechanical properties of enzyme-induced carbonate precipitation-reinforced sea sand [J]. | 岩石力学与岩土工程学报（英文版） , 2024 , 16 (1) : 291-302 . |
| MLA | Ming Huang et al. "Effect of drying-wetting cycles on pore characteristics and mechanical properties of enzyme-induced carbonate precipitation-reinforced sea sand" . | 岩石力学与岩土工程学报（英文版） 16 . 1 (2024) : 291-302 . |
| APA | Ming Huang , Kai Xu , Zijian Liu , Chaoshui Xu , Mingjuan Cui . Effect of drying-wetting cycles on pore characteristics and mechanical properties of enzyme-induced carbonate precipitation-reinforced sea sand . | 岩石力学与岩土工程学报（英文版） , 2024 , 16 (1) , 291-302 . |
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In this study, enzyme-induced carbonate precipitation (EICP) combined with xanthan gum curing technology was used to improve the engineering properties of standard sand, and the curing effect of EICP combined with different xanthan gum contents was studied by macroscopic tests such as unconfined compressive strength, direct shear, permeability, calcium carbonate content, and microscopic tests such as scanning electron microscope and nuclear magnetic resonance. The results show that the unconfined compressive strength, shear strength, cohesion and internal friction angle of EICP combined with xanthan gum solidified sand increases with the increase of xanthan gum content and reaches the maximum value at the content of 2%, in which the increase of unconfined compressive strength, shear strength, and cohesion is significant; further, the increase of internal friction angle is small. The permeability coefficient of EICP combined with xanthan gum solidified sand decreases with the increase of xanthan gum content, and the permeability coefficient of 2% xanthan gum is only 65.4% that of pure EICP treatment. The incorporation of xanthan gum promotes the deposition of calcium carbonate, increases the viscosity of the reaction solution, and produces colloidal encapsulation and bonding effect on the sand particles. In addition, the incorporation of xanthan gum effectively reduces the porosity of solidified sand and greatly reduces the proportion of large pores and medium pores by changing the pore size, which greatly improves the pore structure.
Keyword ：
Enzyme-induced carbonate precipitation (EICP) Enzyme-induced carbonate precipitation (EICP) Multiscale engineering properties Multiscale engineering properties Soybean urease Soybean urease Standard sand Standard sand Xanthan gum Xanthan gum
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| GB/T 7714 | Cui, Meng , Xiong, Huihui , Zheng, Junjie et al. Experimental Study on Multiscale Engineering Properties of EICP Combined with Xanthan Gum Solidified Sand [J]. | JOURNAL OF MATERIALS IN CIVIL ENGINEERING , 2024 , 36 (6) . |
| MLA | Cui, Meng et al. "Experimental Study on Multiscale Engineering Properties of EICP Combined with Xanthan Gum Solidified Sand" . | JOURNAL OF MATERIALS IN CIVIL ENGINEERING 36 . 6 (2024) . |
| APA | Cui, Meng , Xiong, Huihui , Zheng, Junjie , Cui, Mingjuan , Lv, Suying , Lai, Hanjiang . Experimental Study on Multiscale Engineering Properties of EICP Combined with Xanthan Gum Solidified Sand . | JOURNAL OF MATERIALS IN CIVIL ENGINEERING , 2024 , 36 (6) . |
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Enzyme-induced carbonate precipitation (EICP) has emerged as an innovative soil stabilization technology to precipitate CaCO3 by catalyzing urea decomposition. Although extensive efforts have been made to increase the calcium carbonate content (CCC) formed in the EICP process for the better bio-cementation effect, the cementability and micromechanical properties of CaCO3 are rarely known. A study of the cementitious characteristics and micromechanical properties of CaCO3 precipitates with different mixing percentages of crystal morphology is essential for soil improvement. In the present study, ultrasonic oscillation tests and nanoindentation tests were performed to investigate the cementability and micromechanical properties of CaCO3 precipitate. The results show that the cementability and micromechanical properties of CaCO3 precipitate are related to the composition of the crystal morphology. A high content of calcite is beneficial to improve the adhesion of calcium carbonate precipitate. Calcite has better mechanical properties (elastic modulus, hardness and ductility) than vaterite, and the presence of vaterite can significantly affect the measured value of mechanical properties in nanoindentation tests. The ductility of CaCO3 precipitate induced by crude soybean urease (CSU) is higher than that of CaCO3 precipitate induced by commercially available pure enzyme, suggesting that commercially available pure enzyme can be replaced by CSU for cost-effective field-scale engineering applications. This work can provide insight into optimizing the properties of CaCO3 precipitate from the micro-scale. © 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
Keyword ：
Cementability Cementability Enzyme-induced carbonate precipitation (EICP) Enzyme-induced carbonate precipitation (EICP) Micromechanical properties Micromechanical properties Nanoindentation tests Nanoindentation tests
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| GB/T 7714 | Xu, K. , Huang, M. , Cui, M. et al. Effect of crystal morphology on cementability and micromechanical properties of calcium carbonate precipitate induced by crude soybean enzyme [J]. | Journal of Rock Mechanics and Geotechnical Engineering , 2024 . |
| MLA | Xu, K. et al. "Effect of crystal morphology on cementability and micromechanical properties of calcium carbonate precipitate induced by crude soybean enzyme" . | Journal of Rock Mechanics and Geotechnical Engineering (2024) . |
| APA | Xu, K. , Huang, M. , Cui, M. , Li, S. . Effect of crystal morphology on cementability and micromechanical properties of calcium carbonate precipitate induced by crude soybean enzyme . | Journal of Rock Mechanics and Geotechnical Engineering , 2024 . |
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There are two major challenges for the use of enzyme-induced carbonate precipitation (EICP)-based soil improvement method: cost and treatment effect. Optimizing the parameters of the treatment solution is one way to enhance the treatment effect and/or reduce the treatment cost. In this study, three key factors: the initial pH (i.e. pH0) of the enzyme solution used to prepare the treatment solution (i.e. the mixture of enzyme solution, CaCl2 and urea), the urease activity of the treatment solution and the concentration of cementation solution (i.e. CaCl2 and urea) are investigated. Crude soybean enzyme solution and the one-phase-low-pH injection method are adopted for the treatment of sand. The results show that the pH0 of the enzyme solution affects the urease activity of enzyme and thus the urease activity of the prepared treatment solution. It is discovered in this paper that there is a threshold pH value for the treatment solution. Only when the pH of the treatment solution is higher than the threshold pH value, calcium ions convert completely into calcium carbonate. There is also a threshold urease activity which is affected by the concentration of cementation solution, CCS. The optimal CCS is 1.0 M. When the CCS is higher than 1.75 M, the urease activity of soybean enzyme solution would be completely lost. These findings are important in guiding the application of EICP treatment using the crude soybean enzyme in real soil improvement projects.
Keyword ：
Crude soybean enzyme Crude soybean enzyme Enzyme-induced carbonate precipitation Enzyme-induced carbonate precipitation Influencing factors Influencing factors Soil improvement Soil improvement
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| GB/T 7714 | Cui, Ming-Juan , Chu, Jian , Lai, Han-Jiang . Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement [J]. | ACTA GEOTECHNICA , 2024 , 19 (3) : 1611-1625 . |
| MLA | Cui, Ming-Juan et al. "Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement" . | ACTA GEOTECHNICA 19 . 3 (2024) : 1611-1625 . |
| APA | Cui, Ming-Juan , Chu, Jian , Lai, Han-Jiang . Optimization of one-phase-low-pH enzyme-induced carbonate precipitation method for soil improvement . | ACTA GEOTECHNICA , 2024 , 19 (3) , 1611-1625 . |
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Calcium salt is an important contributing factor for calcium-based biomineralization. To study the effect of calcium salt on soil biomineralization using crude soybean urease, the calcium salts, including the calcium chloride (CaCl2), calcium acetate ((CH3COO)2Ca) and calcium nitrate (Ca(NO3)2), were used to prepare the biotreatment solution to carry out the biomineralization tests in this paper. Two series of biomineralization tests in solution and sand column, respectively, were conducted. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO3) crystals. The experimental results indicate that the biomineralization effect is the best for the CaCl2 case, followed by (CH3COO)2Ca, and worst for Ca(NO3)2 under the test conditions of this study (i.e. 1 mol/L of calcium salt-urea). The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity, and (2) influence on the crystal size and morphology of CaCO3. Besides Ca2+, the anions in solution can inhibit the activity of crude soybean urease, and NO3− has a stronger inhibitory effect on the urease activity compared with both CH3COO− and Cl−. The co-inhibition of Ca2+ and NO3− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO3)2 case in this study. The difference in biomineralization between the CaCl2 and (CH3COO)2Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO3. © 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences
Keyword ：
Biomineralization Biomineralization Calcium salt Calcium salt Crude soybean urease Crude soybean urease Influence mechanism Influence mechanism
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| GB/T 7714 | Weng, Y. , Zheng, J. , Lai, H. et al. Biomineralization of soil with crude soybean urease using different calcium salts [J]. | Journal of Rock Mechanics and Geotechnical Engineering , 2024 , 16 (5) : 1788-1798 . |
| MLA | Weng, Y. et al. "Biomineralization of soil with crude soybean urease using different calcium salts" . | Journal of Rock Mechanics and Geotechnical Engineering 16 . 5 (2024) : 1788-1798 . |
| APA | Weng, Y. , Zheng, J. , Lai, H. , Cui, M. , Ding, X. . Biomineralization of soil with crude soybean urease using different calcium salts . | Journal of Rock Mechanics and Geotechnical Engineering , 2024 , 16 (5) , 1788-1798 . |
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In this study, enzyme-induced carbonate precipitation (EICP) combined with chitosan curing technology was used to improve the mechanical properties of standard sand, and the curing effect of EICP combined with different chitosan contents was studied by macroscopic tests, such as the unconfined compressive strength test, direct shear test, and calcium carbonate content test, and microscopic tests, such as scanning electron microscope (SEM) and nuclear magnetic resonance (NMR). The results show that compared with the pure EICP treatment, the unconfined compressive strength, shear strength, and calcium carbonate content of the sand treated by EICP combined with chitosan were significantly improved, and increased first and then decreased with the increase of chitosan content, reaching the maximum value when the content is 1.5%. The calcium carbonate content is positively correlated with the strength, indicating that calcium carbonate crystals can effectively play a role in filling and cementation. After the incorporation of chitosan, the shape of calcium carbonate crystals is still mainly spherical, but the number and volume become larger. At the same time, the incorporation of chitosan can greatly reduce the proportion of large pores and medium pores, significantly increasing the proportion of small pores, which greatly improves the pore structure.
Keyword ：
Chitosan Chitosan Enzyme-induced carbonate precipitation Enzyme-induced carbonate precipitation Soil improvement Soil improvement Soybean urease Soybean urease Strength Strength
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| GB/T 7714 | Cui, Meng , Xiong, Huihui , Zheng, Junjie et al. Strength Investigation of Sand Treated by Enzyme-Induced Carbonate Precipitation Combined with Chitosan [J]. | INTERNATIONAL JOURNAL OF GEOMECHANICS , 2024 , 24 (6) . |
| MLA | Cui, Meng et al. "Strength Investigation of Sand Treated by Enzyme-Induced Carbonate Precipitation Combined with Chitosan" . | INTERNATIONAL JOURNAL OF GEOMECHANICS 24 . 6 (2024) . |
| APA | Cui, Meng , Xiong, Huihui , Zheng, Junjie , Cui, Mingjuan , Lv, Suying , Han, Shangyu . Strength Investigation of Sand Treated by Enzyme-Induced Carbonate Precipitation Combined with Chitosan . | INTERNATIONAL JOURNAL OF GEOMECHANICS , 2024 , 24 (6) . |
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In this study, Enzyme-Induced Carbonate Precipitation (EICP) combined with polypropylene fiber technology was used to solidify desert sand, the orthogonal theory was used to design the different levels of the five test variables of cementation solution concentration, urease concentration, enzyme gel ratio, fiber length and fiber content, and the curing effect of EICP combined with polypropylene fiber was studied by macroscopic test of unconfined compressive strength and calcium carbonate content and microscopic test of scanning electron microscope (SEM) and nuclear magnetic resonance (NMR). The results show that the primary and secondary order of the influence of the five test variables on the unconfined compressive strength and calcium carbonate content is: fiber content >fiber length >urease concentration >enzyme gel ratio >cementation solution concentration, in which the fiber length and fiber content had a significant effect on it, and the urease concentration had a little significant effect on it. The incorporation of polypropylene fiber promotes the deposition of calcium carbonate, restricts the displacement and deformation of sand particles, effectively fills the pores between particles, significantly reduces the pore size, and improves the pore structure, which provides a reference for subsequent research and practical geotechnical applications.
Keyword ：
Desert sand Desert sand Enzyme-induced carbonate Enzyme-induced carbonate Multivariate Multivariate Polypropylene fiber Polypropylene fiber precipitation precipitation Soybean urease Soybean urease
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| GB/T 7714 | Cui, Meng , Xiong, Huihui , Lv, Suying et al. Multivariate Experimental Study on EICP Combined with Polypropylene Fiber Solidified Desert Sand [J]. | KSCE JOURNAL OF CIVIL ENGINEERING , 2024 , 28 (6) : 2221-2230 . |
| MLA | Cui, Meng et al. "Multivariate Experimental Study on EICP Combined with Polypropylene Fiber Solidified Desert Sand" . | KSCE JOURNAL OF CIVIL ENGINEERING 28 . 6 (2024) : 2221-2230 . |
| APA | Cui, Meng , Xiong, Huihui , Lv, Suying , Zheng, Junjie , Cui, Mingjuan , Zeng, Chen . Multivariate Experimental Study on EICP Combined with Polypropylene Fiber Solidified Desert Sand . | KSCE JOURNAL OF CIVIL ENGINEERING , 2024 , 28 (6) , 2221-2230 . |
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TBM(tunnel boring machine,简称TBM)隧道中豆砾石作为管片与围岩填充层对管片承载及抗渗具有重要意义,水泥浆液流动性差,无法充满回填层进而导致壁后空洞、灌浆不密实等缺陷,酶诱导碳酸钙沉淀(enzyme-induced calcium carbonate precipitation,简称EICP)技术是作为一种环保高效的加固方法,灌浆材料均为液体具有很好的流动性和扩散性,用于豆砾石回填层灌浆施工有望解决上述问题.为实现吹填豆粒石EICP灌浆最优效果,尝试将标准砂与豆砾石共同作为回填骨料,为定量化分析二者的最优配合比,开展了不同豆砾石与砂的配合比(0.5、0.75、1.0、1.25、1.5)和不同灌浆次数(9、12、15次)的砂柱固化试验.通过无侧限抗压测试、渗透性测试、碳酸钙含量测定、超声波速测定、扫描电镜(scanning electron microscope,简称SEM)试验,从宏观和微观角度分析不同石砂配合比对EICP固化效果的影响.结果表明:EICP加固豆砾石混合砂的最优配比为1∶1.5,经15次灌浆加固后,试样单轴抗压强度最高可达4.55 MPa,渗透系数达1.72×10-5m/s;对于含砂量较高的试样,颗粒间孔隙易被碳酸钙晶体填充密实,碳酸钙晶体有效胶结比例较高,结石体无侧限抗压强度较高.研究成果可为EICP技术加固隧道掘进机壁后吹填豆粒石的工程应用提供理论依据.
Keyword ：
微观机制 微观机制 无侧限抗压强度 无侧限抗压强度 渗透性 渗透性 豆砾石 豆砾石 酶诱导碳酸钙沉淀技术(EICP) 酶诱导碳酸钙沉淀技术(EICP) 隧道掘进机 隧道掘进机
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| GB/T 7714 | 姜启武 , 黄明 , 崔明娟 et al. 酶诱导碳酸钙沉淀技术加固TBM壁后吹填豆砾石最优配比试验及机制研究 [J]. | 岩土力学 , 2024 , 45 (7) : 2037-2049 . |
| MLA | 姜启武 et al. "酶诱导碳酸钙沉淀技术加固TBM壁后吹填豆砾石最优配比试验及机制研究" . | 岩土力学 45 . 7 (2024) : 2037-2049 . |
| APA | 姜启武 , 黄明 , 崔明娟 , 靳贵晓 , 彭仪欣 . 酶诱导碳酸钙沉淀技术加固TBM壁后吹填豆砾石最优配比试验及机制研究 . | 岩土力学 , 2024 , 45 (7) , 2037-2049 . |
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Abstract ：
TBM 隧道中豆砾石作为管片与围岩填充层对管片承载及抗渗具有重要意义，水泥浆液流动性差，无法充满回填层进而导致壁后空洞、灌浆不密实等缺陷，酶诱导碳酸钙沉淀技术（EICP）是作为一种环保高效的加固方法，灌浆材料均为液体具有很好的流动性和扩散性，用于豆砾石回填层灌浆施工有望解决上述问题。为实现吹填豆粒石EICP灌浆最优效果，尝试将标准砂与豆砾石共同作为回填骨料，为定量化分析二者的最优配合比，开展了不同豆砾石与砂的配合比（0.5、0.75、1.0、1.25、1.5）和不同灌浆次数（9、12、15次）的砂柱固化试验。通过无侧限抗压测试、渗透性测试、碳酸钙含量测定、超声波速测定、SEM微观分析，从宏观和微观角度分析不同石砂配合比对EICP固化效果的影响。结果表明：EICP加固豆砾石混合砂的最优配比为1:1.5，经15次灌浆加固后，试样单轴抗压强度最高可达4.55 MPa，渗透系数达1.72×10~(-5 )m/s；对于含砂量较高的试样，颗粒间孔隙易被碳酸钙晶体填充密实，碳酸钙晶体有效胶结比例较高，结石体无侧限抗压强度较高。研究成果可为EICP技术加固TBM壁后吹填豆粒石的工程应用提供理论依据。
Keyword ：
微观机理 微观机理 无侧限抗压强度 无侧限抗压强度 渗透性 渗透性 豆砾石 豆砾石 酶诱导碳酸钙沉淀技术(EICP) 酶诱导碳酸钙沉淀技术(EICP) 隧道掘进机 隧道掘进机
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| GB/T 7714 | 姜启武 , 黄明 , 崔明娟 et al. EICP技术加固TBM壁后吹填豆砾石最优配比试验及机理研究 [J]. | 岩土力学 , 2024 , (07) . |
| MLA | 姜启武 et al. "EICP技术加固TBM壁后吹填豆砾石最优配比试验及机理研究" . | 岩土力学 07 (2024) . |
| APA | 姜启武 , 黄明 , 崔明娟 , 靳贵晓 , 彭仪欣 . EICP技术加固TBM壁后吹填豆砾石最优配比试验及机理研究 . | 岩土力学 , 2024 , (07) . |
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In tropical islands, calcareous sand with poor engineering properties usually needs to be treated before it can be used as building materials. Considering the scarcity of freshwater in these areas, this study proposes seawater-based enzyme induced carbonate precipitation (EICP) technology to enhance the properties of calcareous sand. It is to induce calcium carbonate crystals to bond calcareous sand particles together using the seawater-based crude soybean enzyme and cementation solution (i.e., urea and calcium chloride). In this study, the crude soybean urease extraction test was firstly carried out using seawater and it was also investigated what components of seawater had a greater effect on the soybean urease extraction. Afterwards, the solution test was conducted to explore the ability of the extracted urease in inducing calcium carbonate through analyzing the variation of concentration of calcium ions and pH of the solution. Finally, the biocementation effect of EICP treated calcareous sand using the seawater extracted urease solution was evaluated by the unconfined compressive strength (quc) and microscopic analysis. Test results show that the turbidity of the seawater-extracted soybean urease solution can be reduced by 66.7% compared to that of deionised water extracted urease, with only a slight reduction in urease activity. Among all the components of seawater, NaCl, MgCl2, CaCl2, NaHCO3 and KBr can significantly reduce the turbidity of soybean urease solution. The lower turbidity can effectively avoid bioclogging and contribute to the homogeneity of the EICP-treated calcareous sands, and thus improve the biomineralization efficiency and strength enhancement. Seawater-based EICP treatment will be a great promising technology in freshwater-scarce tropical islands, because it can directly use seawater for biomineralization treatment of calcareous sand, and meanwhile effectively avoid local clogging of biocementation.
Keyword ：
Biomineralization Biomineralization Calcareous sand Calcareous sand Enzyme induced carbonate precipitation (EICP) Enzyme induced carbonate precipitation (EICP) Seawater Seawater Soybean urease extraction Soybean urease extraction
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| GB/T 7714 | Cui, Ming-Juan , Zhou, Jia-Ni , Lai, Han-Jiang et al. Seawater-based soybean urease for calcareous sand biomineralization [J]. | ACTA GEOTECHNICA , 2024 , 19 (10) : 6643-6659 . |
| MLA | Cui, Ming-Juan et al. "Seawater-based soybean urease for calcareous sand biomineralization" . | ACTA GEOTECHNICA 19 . 10 (2024) : 6643-6659 . |
| APA | Cui, Ming-Juan , Zhou, Jia-Ni , Lai, Han-Jiang , Zheng, Jun-Jie , Huang, Ming , Zhang, Zhi-Chao . Seawater-based soybean urease for calcareous sand biomineralization . | ACTA GEOTECHNICA , 2024 , 19 (10) , 6643-6659 . |
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