Study on the mechanism of gas migration and breakthrough in saturated bentonite considering the interface effect
IntroductionGas migration in low-permeability buffer materials is a crucial aspect of nuclear waste disposal. This study focuses on Gaomiaozi bentonite to investigate its behavior under various conditions.MethodsWe developed a coupled hydro-mechanical model that incorporates damage mechanisms in ben...
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Frontiers Media S.A.
2025-01-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2024.1500055/full |
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| author | Daoping Liu Jingna Guo Qiang Li Qiang Li Zhanqing Chen Zhanqing Chen |
| author_facet | Daoping Liu Jingna Guo Qiang Li Qiang Li Zhanqing Chen Zhanqing Chen |
| author_sort | Daoping Liu |
| collection | DOAJ |
| description | IntroductionGas migration in low-permeability buffer materials is a crucial aspect of nuclear waste disposal. This study focuses on Gaomiaozi bentonite to investigate its behavior under various conditions.MethodsWe developed a coupled hydro-mechanical model that incorporates damage mechanisms in bentonite under flexible boundary conditions. Utilizing the elastic theory of porous media, gas pressure was integrated into the soil's constitutive equation. The model accounted for damage effects on the elastic modulus and permeability, with damage variables defined by the Galileo and Coulomb-Mohr criteria. We conducted numerical simulations of the seepage and stress fields using COMSOL and MATLAB. Gas breakthrough tests were also performed on bentonite samples under controlled conditions.ResultsThe permeability obtained from gas breakthrough tests and numerical simulations was within a 10% error margin. The experimentally measured gas breakthrough pressure aligned closely with the predicted values, validating the model's applicability.DiscussionAnalysis revealed that increased dry density under flexible boundaries reduced the damage area and influenced gas breakthrough pressure. Specifically, at dry densities of 1.4 g/cm3, 1.6 g/cm3, and 1.7 g/cm3, the corresponding gas breakthrough pressures were 5.0 MPa, 6.0 MPa, and 6.5 MPa, respectively. At a dry density of 1.8 g/cm3 and an injection pressure of 10.0 MPa, no continuous seepage channels formed, indicating no gas breakthrough. This phenomenon is attributed to the greater tensile and compressive strengths associated with higher dry densities, which render the material less susceptible to damage from external forces. |
| format | Article |
| id | doaj-art-0e9eb56a771b45e9b20a55a1d278fdba |
| institution | Kabale University |
| issn | 2296-6463 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Earth Science |
| spelling | doaj-art-0e9eb56a771b45e9b20a55a1d278fdba2025-01-06T06:58:45ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-01-011210.3389/feart.2024.15000551500055Study on the mechanism of gas migration and breakthrough in saturated bentonite considering the interface effectDaoping Liu0Jingna Guo1Qiang Li2Qiang Li3Zhanqing Chen4Zhanqing Chen5Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chendu, ChinaSchool of Applied Mathematics, Chengdu University of Information Technology, Chengdu, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, ChinaState Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China University of Mining and Technology, Xuzhou, ChinaSchool of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, ChinaIntroductionGas migration in low-permeability buffer materials is a crucial aspect of nuclear waste disposal. This study focuses on Gaomiaozi bentonite to investigate its behavior under various conditions.MethodsWe developed a coupled hydro-mechanical model that incorporates damage mechanisms in bentonite under flexible boundary conditions. Utilizing the elastic theory of porous media, gas pressure was integrated into the soil's constitutive equation. The model accounted for damage effects on the elastic modulus and permeability, with damage variables defined by the Galileo and Coulomb-Mohr criteria. We conducted numerical simulations of the seepage and stress fields using COMSOL and MATLAB. Gas breakthrough tests were also performed on bentonite samples under controlled conditions.ResultsThe permeability obtained from gas breakthrough tests and numerical simulations was within a 10% error margin. The experimentally measured gas breakthrough pressure aligned closely with the predicted values, validating the model's applicability.DiscussionAnalysis revealed that increased dry density under flexible boundaries reduced the damage area and influenced gas breakthrough pressure. Specifically, at dry densities of 1.4 g/cm3, 1.6 g/cm3, and 1.7 g/cm3, the corresponding gas breakthrough pressures were 5.0 MPa, 6.0 MPa, and 6.5 MPa, respectively. At a dry density of 1.8 g/cm3 and an injection pressure of 10.0 MPa, no continuous seepage channels formed, indicating no gas breakthrough. This phenomenon is attributed to the greater tensile and compressive strengths associated with higher dry densities, which render the material less susceptible to damage from external forces.https://www.frontiersin.org/articles/10.3389/feart.2024.1500055/fullrigid boundaryinterface effect between bentonite blocksmechanism of gas migrationtwo-phase flow effectgas breakthrough |
| spellingShingle | Daoping Liu Jingna Guo Qiang Li Qiang Li Zhanqing Chen Zhanqing Chen Study on the mechanism of gas migration and breakthrough in saturated bentonite considering the interface effect Frontiers in Earth Science rigid boundary interface effect between bentonite blocks mechanism of gas migration two-phase flow effect gas breakthrough |
| title | Study on the mechanism of gas migration and breakthrough in saturated bentonite considering the interface effect |
| title_full | Study on the mechanism of gas migration and breakthrough in saturated bentonite considering the interface effect |
| title_fullStr | Study on the mechanism of gas migration and breakthrough in saturated bentonite considering the interface effect |
| title_full_unstemmed | Study on the mechanism of gas migration and breakthrough in saturated bentonite considering the interface effect |
| title_short | Study on the mechanism of gas migration and breakthrough in saturated bentonite considering the interface effect |
| title_sort | study on the mechanism of gas migration and breakthrough in saturated bentonite considering the interface effect |
| topic | rigid boundary interface effect between bentonite blocks mechanism of gas migration two-phase flow effect gas breakthrough |
| url | https://www.frontiersin.org/articles/10.3389/feart.2024.1500055/full |
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