Creep Mechanics of the High-Stress Soft Rock under Grade Unloading
In order to study the creep behavior of deep soft rock, gritstone was chosen as the research subject, and a rock triaxial rheometer (Rock 600-50) and acoustic emission (AE) system (SH-II) were used to carry out the grade unloading confining pressure creep test under a high-stress level. The test res...
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| Format: | Article |
| Language: | English |
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Wiley
2020-01-01
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| Series: | Advances in Civil Engineering |
| Online Access: | http://dx.doi.org/10.1155/2020/8822265 |
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| author | Shunjie Huang Xiangrui Meng Guangming Zhao Yingming Li Gang Liu Chunliang Dong Xiang Cheng Wensong Xu Chongyan Liu Jun Zhou |
| author_facet | Shunjie Huang Xiangrui Meng Guangming Zhao Yingming Li Gang Liu Chunliang Dong Xiang Cheng Wensong Xu Chongyan Liu Jun Zhou |
| author_sort | Shunjie Huang |
| collection | DOAJ |
| description | In order to study the creep behavior of deep soft rock, gritstone was chosen as the research subject, and a rock triaxial rheometer (Rock 600-50) and acoustic emission (AE) system (SH-II) were used to carry out the grade unloading confining pressure creep test under a high-stress level. The test results showed that the lateral creep behavior of the gritstone was more prominent than the axial creep under the initial high confining pressure. Under the same confining pressure, the creep strain rate (the direction the same as strain) of the gritstone decreases with the increase in axial pressure. As shown by the AE count, AE signals were generated throughout the entire test process, indicating that the creep was a “microdynamic” process. The creep behavior was characterized by a significant confining pressure effect. As the confining pressure was decreased, the degree of creep increases significantly. During the test, the AE energy increased on the whole but decreases during the creep phase. During the entire test process, the overall energy in the constant deviatoric stress grade unloading of the confining pressure was 45% higher than that in the constant axial pressure grade unloading. The degree of failure of the rock was different in these two unloading creep tests, and the constant axial pressure grade unloading of the confining pressure entails greater damage than the constant deviatoric stress grade unloading of the confining pressure. The main reason was that the former had a lower confining pressure level and longer creep process than the latter, and the sample was mainly characterized by creep damage and large cumulative damage, while the latter features mainly unloading damage. Through the inversion of the Burgers constitutive model and nonlinear damage constitutive model for the creep test curve, the nonlinear constitutive equation can better fit the accelerated creep stage, which suggested that this model can describe the accelerated creep characteristics of the high-stress soft rock. |
| format | Article |
| id | doaj-art-96d53c6c9f81403d99ef003fdbaaa986 |
| institution | OA Journals |
| issn | 1687-8086 1687-8094 |
| language | English |
| publishDate | 2020-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Civil Engineering |
| spelling | doaj-art-96d53c6c9f81403d99ef003fdbaaa9862025-08-20T02:09:49ZengWileyAdvances in Civil Engineering1687-80861687-80942020-01-01202010.1155/2020/88222658822265Creep Mechanics of the High-Stress Soft Rock under Grade UnloadingShunjie Huang0Xiangrui Meng1Guangming Zhao2Yingming Li3Gang Liu4Chunliang Dong5Xiang Cheng6Wensong Xu7Chongyan Liu8Jun Zhou9State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaState Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines, Anhui University of Science and Technology, Huainan 232001, ChinaIn order to study the creep behavior of deep soft rock, gritstone was chosen as the research subject, and a rock triaxial rheometer (Rock 600-50) and acoustic emission (AE) system (SH-II) were used to carry out the grade unloading confining pressure creep test under a high-stress level. The test results showed that the lateral creep behavior of the gritstone was more prominent than the axial creep under the initial high confining pressure. Under the same confining pressure, the creep strain rate (the direction the same as strain) of the gritstone decreases with the increase in axial pressure. As shown by the AE count, AE signals were generated throughout the entire test process, indicating that the creep was a “microdynamic” process. The creep behavior was characterized by a significant confining pressure effect. As the confining pressure was decreased, the degree of creep increases significantly. During the test, the AE energy increased on the whole but decreases during the creep phase. During the entire test process, the overall energy in the constant deviatoric stress grade unloading of the confining pressure was 45% higher than that in the constant axial pressure grade unloading. The degree of failure of the rock was different in these two unloading creep tests, and the constant axial pressure grade unloading of the confining pressure entails greater damage than the constant deviatoric stress grade unloading of the confining pressure. The main reason was that the former had a lower confining pressure level and longer creep process than the latter, and the sample was mainly characterized by creep damage and large cumulative damage, while the latter features mainly unloading damage. Through the inversion of the Burgers constitutive model and nonlinear damage constitutive model for the creep test curve, the nonlinear constitutive equation can better fit the accelerated creep stage, which suggested that this model can describe the accelerated creep characteristics of the high-stress soft rock.http://dx.doi.org/10.1155/2020/8822265 |
| spellingShingle | Shunjie Huang Xiangrui Meng Guangming Zhao Yingming Li Gang Liu Chunliang Dong Xiang Cheng Wensong Xu Chongyan Liu Jun Zhou Creep Mechanics of the High-Stress Soft Rock under Grade Unloading Advances in Civil Engineering |
| title | Creep Mechanics of the High-Stress Soft Rock under Grade Unloading |
| title_full | Creep Mechanics of the High-Stress Soft Rock under Grade Unloading |
| title_fullStr | Creep Mechanics of the High-Stress Soft Rock under Grade Unloading |
| title_full_unstemmed | Creep Mechanics of the High-Stress Soft Rock under Grade Unloading |
| title_short | Creep Mechanics of the High-Stress Soft Rock under Grade Unloading |
| title_sort | creep mechanics of the high stress soft rock under grade unloading |
| url | http://dx.doi.org/10.1155/2020/8822265 |
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