Frictional behavior of planar and rough granite fractures subjected to normal load oscillations of different amplitudes
The dynamic frictional behaviors of natural discontinuities (joints, fractures, faults) play an important role in geohazards assessment; however, the mechanisms of the dynamic fault weakening/strengthening are still unclear. In this paper, a dynamic shear box was used to perform direct shear tests o...
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| Format: | Article |
| Language: | English |
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Elsevier
2022-06-01
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| Series: | Journal of Rock Mechanics and Geotechnical Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674775521001529 |
| _version_ | 1811231711244058624 |
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| author | Wengang Dang Kang Tao Xinfan Chen |
| author_facet | Wengang Dang Kang Tao Xinfan Chen |
| author_sort | Wengang Dang |
| collection | DOAJ |
| description | The dynamic frictional behaviors of natural discontinuities (joints, fractures, faults) play an important role in geohazards assessment; however, the mechanisms of the dynamic fault weakening/strengthening are still unclear. In this paper, a dynamic shear box was used to perform direct shear tests on saw-cut (planar) and natural (rough) granite fractures, with different normal load oscillation amplitudes. Based on the recorded shear forces and normal displacements, the shear forces, apparent friction coefficients and normal displacements are found to change periodically with oscillated normal loads and are characterized by a series of time shifts. The observed changing patterns are similar for the rough and planar fractures. Compared with the test data under constant normal load (CNL), small/large normal load oscillation amplitude enhances/reduces the peak shear strength, with a critical point. The magnitude of critical normal load oscillation for the rough fractures is smaller than the planer fractures. The results imply that dynamic fault weakening/strengthening can be achieved by both normal load oscillation amplitudes and slip surface topography. The rough fractures with larger normal oscillation amplitude can easily cause frictional weakening under stress disturbance. |
| first_indexed | 2024-04-12T10:49:25Z |
| format | Article |
| id | doaj.art-ea9ed66ba35847f7a9da40eebf1ee62a |
| institution | Directory Open Access Journal |
| issn | 1674-7755 |
| language | English |
| last_indexed | 2024-04-12T10:49:25Z |
| publishDate | 2022-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Rock Mechanics and Geotechnical Engineering |
| spelling | doaj.art-ea9ed66ba35847f7a9da40eebf1ee62a2022-12-22T03:36:18ZengElsevierJournal of Rock Mechanics and Geotechnical Engineering1674-77552022-06-01143746756Frictional behavior of planar and rough granite fractures subjected to normal load oscillations of different amplitudesWengang Dang0Kang Tao1Xinfan Chen2School of Civil Engineering, Sun Yat-sen University, Zhuhai, 519082, China; State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Xuzhou, 221116, China; Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai, 519082, ChinaSchool of Civil Engineering, Sun Yat-sen University, Zhuhai, 519082, China; Corresponding author.School of Civil Engineering, Sun Yat-sen University, Zhuhai, 519082, ChinaThe dynamic frictional behaviors of natural discontinuities (joints, fractures, faults) play an important role in geohazards assessment; however, the mechanisms of the dynamic fault weakening/strengthening are still unclear. In this paper, a dynamic shear box was used to perform direct shear tests on saw-cut (planar) and natural (rough) granite fractures, with different normal load oscillation amplitudes. Based on the recorded shear forces and normal displacements, the shear forces, apparent friction coefficients and normal displacements are found to change periodically with oscillated normal loads and are characterized by a series of time shifts. The observed changing patterns are similar for the rough and planar fractures. Compared with the test data under constant normal load (CNL), small/large normal load oscillation amplitude enhances/reduces the peak shear strength, with a critical point. The magnitude of critical normal load oscillation for the rough fractures is smaller than the planer fractures. The results imply that dynamic fault weakening/strengthening can be achieved by both normal load oscillation amplitudes and slip surface topography. The rough fractures with larger normal oscillation amplitude can easily cause frictional weakening under stress disturbance.http://www.sciencedirect.com/science/article/pii/S1674775521001529Direct shear testNormal load oscillation fracture roughnessCritical oscillation amplitudeDynamic weakening/strengthening |
| spellingShingle | Wengang Dang Kang Tao Xinfan Chen Frictional behavior of planar and rough granite fractures subjected to normal load oscillations of different amplitudes Journal of Rock Mechanics and Geotechnical Engineering Direct shear test Normal load oscillation fracture roughness Critical oscillation amplitude Dynamic weakening/strengthening |
| title | Frictional behavior of planar and rough granite fractures subjected to normal load oscillations of different amplitudes |
| title_full | Frictional behavior of planar and rough granite fractures subjected to normal load oscillations of different amplitudes |
| title_fullStr | Frictional behavior of planar and rough granite fractures subjected to normal load oscillations of different amplitudes |
| title_full_unstemmed | Frictional behavior of planar and rough granite fractures subjected to normal load oscillations of different amplitudes |
| title_short | Frictional behavior of planar and rough granite fractures subjected to normal load oscillations of different amplitudes |
| title_sort | frictional behavior of planar and rough granite fractures subjected to normal load oscillations of different amplitudes |
| topic | Direct shear test Normal load oscillation fracture roughness Critical oscillation amplitude Dynamic weakening/strengthening |
| url | http://www.sciencedirect.com/science/article/pii/S1674775521001529 |
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