Method of calculating shear strength of rock mass joint surface considering cyclic shear degradation
Abstract When a rock mass shears along a joint surface, the shear resistance is affected by joint surface undulations and friction between the contact regions. During an earthquake, the seismic load causes dynamic deterioration of the joint surface mechanical properties, mostly reflected as follows....
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Nature Portfolio
2022-06-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-022-13505-6 |
| _version_ | 1818207433744449536 |
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| author | Shan Dong Heng Zhang Yulin Peng Zhichun Lu Weihua Hou |
| author_facet | Shan Dong Heng Zhang Yulin Peng Zhichun Lu Weihua Hou |
| author_sort | Shan Dong |
| collection | DOAJ |
| description | Abstract When a rock mass shears along a joint surface, the shear resistance is affected by joint surface undulations and friction between the contact regions. During an earthquake, the seismic load causes dynamic deterioration of the joint surface mechanical properties, mostly reflected as follows. (1) The peak shear strength of the joint surface decreases with an increase in the shear rate. (2) Under a seismic load cyclic shear, the undulant angle α k decreases. (3) Under a dynamic load, the friction coefficient of the joint surface is reduced. By studying the cyclic shear test of the joint surface, the strength deterioration effect of the joint surface under cyclic shearing is first analysed, and the equations of the dilatation angle and the basic friction angle of the joint surface under the cyclic shearing load are proposed. Then, starting with the effect of cyclic shear deterioration on the joint surface in the rock mass and the reduction in the dynamic friction coefficient between sliding rock blocks caused by relative velocity, an equation for calculating the shear strength of a rock mass joint surface under cyclic shear loading is recommended. Through two case calculations, the shear strength obtained using the proposed method is compared with the experimental results. The results show that the model proposed in this study is in good agreement with the experimental results and can also be used to calculate the structural surface shear strength of the asperity-rich sample. However, when the calculation equation is used to estimate the cyclic shear strength of the joint surface where the sum of the initial undulation angle and the basic friction angle is greater than 70°, there may be some errors in the calculation results. |
| first_indexed | 2024-12-12T04:28:51Z |
| format | Article |
| id | doaj.art-1dc47c0118ac47058cf1b73a4b0fdad7 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-12-12T04:28:51Z |
| publishDate | 2022-06-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-1dc47c0118ac47058cf1b73a4b0fdad72022-12-22T00:38:08ZengNature PortfolioScientific Reports2045-23222022-06-0112111410.1038/s41598-022-13505-6Method of calculating shear strength of rock mass joint surface considering cyclic shear degradationShan Dong0Heng Zhang1Yulin Peng2Zhichun Lu3Weihua Hou4Badong National Observation and Research Station of Geohazards, China University of GeosciencesBadong National Observation and Research Station of Geohazards, China University of GeosciencesBadong National Observation and Research Station of Geohazards, China University of GeosciencesBadong National Observation and Research Station of Geohazards, China University of GeosciencesBadong National Observation and Research Station of Geohazards, China University of GeosciencesAbstract When a rock mass shears along a joint surface, the shear resistance is affected by joint surface undulations and friction between the contact regions. During an earthquake, the seismic load causes dynamic deterioration of the joint surface mechanical properties, mostly reflected as follows. (1) The peak shear strength of the joint surface decreases with an increase in the shear rate. (2) Under a seismic load cyclic shear, the undulant angle α k decreases. (3) Under a dynamic load, the friction coefficient of the joint surface is reduced. By studying the cyclic shear test of the joint surface, the strength deterioration effect of the joint surface under cyclic shearing is first analysed, and the equations of the dilatation angle and the basic friction angle of the joint surface under the cyclic shearing load are proposed. Then, starting with the effect of cyclic shear deterioration on the joint surface in the rock mass and the reduction in the dynamic friction coefficient between sliding rock blocks caused by relative velocity, an equation for calculating the shear strength of a rock mass joint surface under cyclic shear loading is recommended. Through two case calculations, the shear strength obtained using the proposed method is compared with the experimental results. The results show that the model proposed in this study is in good agreement with the experimental results and can also be used to calculate the structural surface shear strength of the asperity-rich sample. However, when the calculation equation is used to estimate the cyclic shear strength of the joint surface where the sum of the initial undulation angle and the basic friction angle is greater than 70°, there may be some errors in the calculation results.https://doi.org/10.1038/s41598-022-13505-6 |
| spellingShingle | Shan Dong Heng Zhang Yulin Peng Zhichun Lu Weihua Hou Method of calculating shear strength of rock mass joint surface considering cyclic shear degradation Scientific Reports |
| title | Method of calculating shear strength of rock mass joint surface considering cyclic shear degradation |
| title_full | Method of calculating shear strength of rock mass joint surface considering cyclic shear degradation |
| title_fullStr | Method of calculating shear strength of rock mass joint surface considering cyclic shear degradation |
| title_full_unstemmed | Method of calculating shear strength of rock mass joint surface considering cyclic shear degradation |
| title_short | Method of calculating shear strength of rock mass joint surface considering cyclic shear degradation |
| title_sort | method of calculating shear strength of rock mass joint surface considering cyclic shear degradation |
| url | https://doi.org/10.1038/s41598-022-13505-6 |
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