Macro-meso failure mechanism and strength criterion of frozen weakly cemented sandstone under triaxial unloading
IntroductionIn the excavation engineering of tunnels and mines in the western cold region, the unloading failure zone is mainly caused by stress release. This study aimed to investigate the deformation and failure mechanism of frozen weakly cemented sandstone (FWCS) when the initial principal stress...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Frontiers Media S.A.
2025-01-01
|
| Series: | Frontiers in Earth Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2024.1518849/full |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1841558718774247424 |
|---|---|
| author | Qinghai Deng Hao Fu Junchao Wang Xiaobiao An Xianzhou Lyu |
| author_facet | Qinghai Deng Hao Fu Junchao Wang Xiaobiao An Xianzhou Lyu |
| author_sort | Qinghai Deng |
| collection | DOAJ |
| description | IntroductionIn the excavation engineering of tunnels and mines in the western cold region, the unloading failure zone is mainly caused by stress release. This study aimed to investigate the deformation and failure mechanism of frozen weakly cemented sandstone (FWCS) when the initial principal stress σ3 was 3, 6, or 10 MPa.MethodsA conventional triaxial compression test and a triaxial unloading test with an unloading rate of 0.05 MPa/s were carried out. Based on the experimental data and mathematical analysis methods, the non-linear criterion was constructed and analyzed. The microfracture characteristics of the damaged surface were studied by scanning electron microscopy (SEM).ResultsThe results show that compared with conventional triaxial compression and room temperature triaxial compression tests, the strength and plastic deformation characteristics of FWCS during unloading were significantly weakened, with transverse deformation and volume strain increased, showing obvious dilatancy characteristics. Unloading reduced the cohesion of FWCS, increased the internal friction angle, and increased the risk of rock failure. Macroscopic and microscopic analysis revealed the failure mechanism of FWCS. The unloading stress ratio was introduced to establish relationships. A non-linear criterion based on the Mohr–Coulomb strength criterion was established, with the power function strength criterion being more accurate in describing the failure of FWCS.DiscussionThis study provides valuable insights into the mechanical properties and failure mechanism of FWCS under unloading conditions, which is beneficial for the excavation engineering of tunnels and mines in the western cold region. |
| format | Article |
| id | doaj-art-ac491d054fac47f5b3af688063464ec3 |
| institution | Kabale University |
| issn | 2296-6463 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj-art-ac491d054fac47f5b3af688063464ec32025-01-06T06:59:01ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-01-011210.3389/feart.2024.15188491518849Macro-meso failure mechanism and strength criterion of frozen weakly cemented sandstone under triaxial unloadingQinghai Deng0Hao Fu1Junchao Wang2Xiaobiao An3Xianzhou Lyu4College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, ChinaCollege of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, ChinaLongshou Mine of Jinchuan Group Co., Ltd., Jinchuan, ChinaCollege of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, ChinaCollege of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, ChinaIntroductionIn the excavation engineering of tunnels and mines in the western cold region, the unloading failure zone is mainly caused by stress release. This study aimed to investigate the deformation and failure mechanism of frozen weakly cemented sandstone (FWCS) when the initial principal stress σ3 was 3, 6, or 10 MPa.MethodsA conventional triaxial compression test and a triaxial unloading test with an unloading rate of 0.05 MPa/s were carried out. Based on the experimental data and mathematical analysis methods, the non-linear criterion was constructed and analyzed. The microfracture characteristics of the damaged surface were studied by scanning electron microscopy (SEM).ResultsThe results show that compared with conventional triaxial compression and room temperature triaxial compression tests, the strength and plastic deformation characteristics of FWCS during unloading were significantly weakened, with transverse deformation and volume strain increased, showing obvious dilatancy characteristics. Unloading reduced the cohesion of FWCS, increased the internal friction angle, and increased the risk of rock failure. Macroscopic and microscopic analysis revealed the failure mechanism of FWCS. The unloading stress ratio was introduced to establish relationships. A non-linear criterion based on the Mohr–Coulomb strength criterion was established, with the power function strength criterion being more accurate in describing the failure of FWCS.DiscussionThis study provides valuable insights into the mechanical properties and failure mechanism of FWCS under unloading conditions, which is beneficial for the excavation engineering of tunnels and mines in the western cold region.https://www.frontiersin.org/articles/10.3389/feart.2024.1518849/fullfrozen weakly cemented sandstoneloading-unloadingconfining pressure unloadingfailure mechanismstrength criterion |
| spellingShingle | Qinghai Deng Hao Fu Junchao Wang Xiaobiao An Xianzhou Lyu Macro-meso failure mechanism and strength criterion of frozen weakly cemented sandstone under triaxial unloading Frontiers in Earth Science frozen weakly cemented sandstone loading-unloading confining pressure unloading failure mechanism strength criterion |
| title | Macro-meso failure mechanism and strength criterion of frozen weakly cemented sandstone under triaxial unloading |
| title_full | Macro-meso failure mechanism and strength criterion of frozen weakly cemented sandstone under triaxial unloading |
| title_fullStr | Macro-meso failure mechanism and strength criterion of frozen weakly cemented sandstone under triaxial unloading |
| title_full_unstemmed | Macro-meso failure mechanism and strength criterion of frozen weakly cemented sandstone under triaxial unloading |
| title_short | Macro-meso failure mechanism and strength criterion of frozen weakly cemented sandstone under triaxial unloading |
| title_sort | macro meso failure mechanism and strength criterion of frozen weakly cemented sandstone under triaxial unloading |
| topic | frozen weakly cemented sandstone loading-unloading confining pressure unloading failure mechanism strength criterion |
| url | https://www.frontiersin.org/articles/10.3389/feart.2024.1518849/full |
| work_keys_str_mv | AT qinghaideng macromesofailuremechanismandstrengthcriterionoffrozenweaklycementedsandstoneundertriaxialunloading AT haofu macromesofailuremechanismandstrengthcriterionoffrozenweaklycementedsandstoneundertriaxialunloading AT junchaowang macromesofailuremechanismandstrengthcriterionoffrozenweaklycementedsandstoneundertriaxialunloading AT xiaobiaoan macromesofailuremechanismandstrengthcriterionoffrozenweaklycementedsandstoneundertriaxialunloading AT xianzhoulyu macromesofailuremechanismandstrengthcriterionoffrozenweaklycementedsandstoneundertriaxialunloading |