State-of-the-Art Review of Utilization of Microbial-Induced Calcite Precipitation for Improving Moisture-Dependent Properties of Unsaturated Soils
Unsaturated soil is a form of natural soil whose pores are filled by air and water. Different from saturated soil, the microstructure of unsaturated soil consists of three phases, namely, the solid phase (soil particle), vapor phase, and liquid phase. Due to the matric suction of soil pores, the hyd...
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| Format: | Article |
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MDPI AG
2023-02-01
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| Series: | Applied Sciences |
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| Online Access: | https://www.mdpi.com/2076-3417/13/4/2502 |
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| author | Jue Li Wenwei Bi Yongsheng Yao Zhengnan Liu |
| author_facet | Jue Li Wenwei Bi Yongsheng Yao Zhengnan Liu |
| author_sort | Jue Li |
| collection | DOAJ |
| description | Unsaturated soil is a form of natural soil whose pores are filled by air and water. Different from saturated soil, the microstructure of unsaturated soil consists of three phases, namely, the solid phase (soil particle), vapor phase, and liquid phase. Due to the matric suction of soil pores, the hydraulic and mechanical behaviors of unsaturated soils present a significant dependence on the moisture condition, which usually results in a series of unpredictable risks, including foundation settlement, landslide, and dam collapse. Microbial-induced calcite precipitation (MICP) is a novel and environmentally friendly technology that can improve the water stability of unsaturated soft or expansive soils. This paper reviews the microscopic mechanisms of MICP and its effect on the mechanical properties of unsaturated soils. The MICP process is mainly affected by the concentration of calcium ions and urea, apart from the concentration of bacteria. The moisture-dependent properties were comparatively analyzed through mechanical models and influence factors on the experimental data among various unsaturated soils. It suggests that the variations in resilient modulus and permanent deformation are strongly related to the extent of MICP applied on unsaturated soils. Finally, the problems in the MICP application, environmental challenges, and further research directions are suggested. |
| first_indexed | 2024-03-11T09:12:15Z |
| format | Article |
| id | doaj.art-9f385fa30bee4f9283a04028fbb18b05 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-11T09:12:15Z |
| publishDate | 2023-02-01 |
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| series | Applied Sciences |
| spelling | doaj.art-9f385fa30bee4f9283a04028fbb18b052023-11-16T18:56:38ZengMDPI AGApplied Sciences2076-34172023-02-01134250210.3390/app13042502State-of-the-Art Review of Utilization of Microbial-Induced Calcite Precipitation for Improving Moisture-Dependent Properties of Unsaturated SoilsJue Li0Wenwei Bi1Yongsheng Yao2Zhengnan Liu3College of Traffic & Transportation, Chongqing Jiaotong University, Chongqing 400074, ChinaSchool of Civil Engineering, Chongqing Jiaotong University, Chongqing 400074, ChinaCollege of Traffic & Transportation, Chongqing Jiaotong University, Chongqing 400074, ChinaHunan Communications Research Institute Co., Ltd., Changsha 410075, ChinaUnsaturated soil is a form of natural soil whose pores are filled by air and water. Different from saturated soil, the microstructure of unsaturated soil consists of three phases, namely, the solid phase (soil particle), vapor phase, and liquid phase. Due to the matric suction of soil pores, the hydraulic and mechanical behaviors of unsaturated soils present a significant dependence on the moisture condition, which usually results in a series of unpredictable risks, including foundation settlement, landslide, and dam collapse. Microbial-induced calcite precipitation (MICP) is a novel and environmentally friendly technology that can improve the water stability of unsaturated soft or expansive soils. This paper reviews the microscopic mechanisms of MICP and its effect on the mechanical properties of unsaturated soils. The MICP process is mainly affected by the concentration of calcium ions and urea, apart from the concentration of bacteria. The moisture-dependent properties were comparatively analyzed through mechanical models and influence factors on the experimental data among various unsaturated soils. It suggests that the variations in resilient modulus and permanent deformation are strongly related to the extent of MICP applied on unsaturated soils. Finally, the problems in the MICP application, environmental challenges, and further research directions are suggested.https://www.mdpi.com/2076-3417/13/4/2502microbial-induced calcite precipitationunsaturated soilswater retention curveresilient moduluspermanent deformation |
| spellingShingle | Jue Li Wenwei Bi Yongsheng Yao Zhengnan Liu State-of-the-Art Review of Utilization of Microbial-Induced Calcite Precipitation for Improving Moisture-Dependent Properties of Unsaturated Soils Applied Sciences microbial-induced calcite precipitation unsaturated soils water retention curve resilient modulus permanent deformation |
| title | State-of-the-Art Review of Utilization of Microbial-Induced Calcite Precipitation for Improving Moisture-Dependent Properties of Unsaturated Soils |
| title_full | State-of-the-Art Review of Utilization of Microbial-Induced Calcite Precipitation for Improving Moisture-Dependent Properties of Unsaturated Soils |
| title_fullStr | State-of-the-Art Review of Utilization of Microbial-Induced Calcite Precipitation for Improving Moisture-Dependent Properties of Unsaturated Soils |
| title_full_unstemmed | State-of-the-Art Review of Utilization of Microbial-Induced Calcite Precipitation for Improving Moisture-Dependent Properties of Unsaturated Soils |
| title_short | State-of-the-Art Review of Utilization of Microbial-Induced Calcite Precipitation for Improving Moisture-Dependent Properties of Unsaturated Soils |
| title_sort | state of the art review of utilization of microbial induced calcite precipitation for improving moisture dependent properties of unsaturated soils |
| topic | microbial-induced calcite precipitation unsaturated soils water retention curve resilient modulus permanent deformation |
| url | https://www.mdpi.com/2076-3417/13/4/2502 |
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