Study on the Degradation Effect of Carbonaceous Shale under the Coupling Effect of Chemical Erosion and High Temperature
The southwest region of China has abundant groundwater and high-temperature geothermal energy. Carbonaceous shale, as one of the typical surrounding rocks in this region, often suffers from deterioration effects due to the coupled action of groundwater chemical erosion and high temperature, which af...
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2024-02-01
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| author | Guangwei Xiong Qiunan Chen Yongchao He Zhenghong Chen Xiaocheng Huang Yunpeng Xie |
| author_facet | Guangwei Xiong Qiunan Chen Yongchao He Zhenghong Chen Xiaocheng Huang Yunpeng Xie |
| author_sort | Guangwei Xiong |
| collection | DOAJ |
| description | The southwest region of China has abundant groundwater and high-temperature geothermal energy. Carbonaceous shale, as one of the typical surrounding rocks in this region, often suffers from deterioration effects due to the coupled action of groundwater chemical erosion and high temperature, which affects the long-term stability of tunnel engineering. In order to investigate the deterioration effects of carbonaceous shale under the coupled action of chemical erosion and high temperature, carbonaceous shale from a tunnel of Lixiang Railway in Yunnan Province was taken as the research object. The microstructure and mineral composition of the samples before and after chemical erosion were obtained with a scanning electron microscope-energy dispersive spectrometer and an X-ray diffraction test. Then, triaxial compression tests were conducted on the samples under different time points and different temperature effects of chemical erosion, and the stress–strain curves and the deterioration laws under a single factor were obtained. An improved numerical simulation method based on the parallel bond model was developed, which can account for the coupled effects of chemical erosion and high temperature on the rock. By simulating the triaxial compression test of carbonaceous shale, the deterioration law of carbonaceous shale under the coupled action was discussed. The results show that chemical erosion has a significant deterioration effect on the triaxial compressive strength of carbonaceous shale, and the degree of deterioration is related to the erosion time. In the first 30 days of erosion, the triaxial compressive strength of carbonaceous shale decreased by 11.38%, which was the largest deterioration range. With the increase in erosion time, the deterioration rate gradually decreased; temperature had a significant threshold effect on the strength of carbonaceous shale, and a clear turning point appeared at about 200 °C. By simulating the deterioration effects of carbonaceous shale under the coupled action of chemical erosion and high temperature, it was found that the longer the duration of chemical erosion, the stronger the temperature sensitivity of carbonaceous shale, and the more serious the loss of compressive strength during the heating process. When the temperature was low, the strength of carbonaceous shale changed little, and some samples even showed an increase in strength; when the temperature was high, the strength of carbonaceous shale decreased significantly, showing deterioration characteristics. The numerical simulation method was compared and verified with the indoor test results, and it was found that the numerical calculation had a good agreement with the test results. |
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| language | English |
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| spelling | doaj.art-0f6d6fdff7ae45bfb53a9d62b245d9d32024-02-09T15:17:47ZengMDPI AGMaterials1996-19442024-02-0117370110.3390/ma17030701Study on the Degradation Effect of Carbonaceous Shale under the Coupling Effect of Chemical Erosion and High TemperatureGuangwei Xiong0Qiunan Chen1Yongchao He2Zhenghong Chen3Xiaocheng Huang4Yunpeng Xie5College of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411201, ChinaCollege of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411201, ChinaCollege of Resource & Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201, ChinaCollege of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411201, ChinaCollege of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411201, ChinaResearch Center of Geotechnical and Structural Engineering, Shandong University, Jinan 250061, ChinaThe southwest region of China has abundant groundwater and high-temperature geothermal energy. Carbonaceous shale, as one of the typical surrounding rocks in this region, often suffers from deterioration effects due to the coupled action of groundwater chemical erosion and high temperature, which affects the long-term stability of tunnel engineering. In order to investigate the deterioration effects of carbonaceous shale under the coupled action of chemical erosion and high temperature, carbonaceous shale from a tunnel of Lixiang Railway in Yunnan Province was taken as the research object. The microstructure and mineral composition of the samples before and after chemical erosion were obtained with a scanning electron microscope-energy dispersive spectrometer and an X-ray diffraction test. Then, triaxial compression tests were conducted on the samples under different time points and different temperature effects of chemical erosion, and the stress–strain curves and the deterioration laws under a single factor were obtained. An improved numerical simulation method based on the parallel bond model was developed, which can account for the coupled effects of chemical erosion and high temperature on the rock. By simulating the triaxial compression test of carbonaceous shale, the deterioration law of carbonaceous shale under the coupled action was discussed. The results show that chemical erosion has a significant deterioration effect on the triaxial compressive strength of carbonaceous shale, and the degree of deterioration is related to the erosion time. In the first 30 days of erosion, the triaxial compressive strength of carbonaceous shale decreased by 11.38%, which was the largest deterioration range. With the increase in erosion time, the deterioration rate gradually decreased; temperature had a significant threshold effect on the strength of carbonaceous shale, and a clear turning point appeared at about 200 °C. By simulating the deterioration effects of carbonaceous shale under the coupled action of chemical erosion and high temperature, it was found that the longer the duration of chemical erosion, the stronger the temperature sensitivity of carbonaceous shale, and the more serious the loss of compressive strength during the heating process. When the temperature was low, the strength of carbonaceous shale changed little, and some samples even showed an increase in strength; when the temperature was high, the strength of carbonaceous shale decreased significantly, showing deterioration characteristics. The numerical simulation method was compared and verified with the indoor test results, and it was found that the numerical calculation had a good agreement with the test results.https://www.mdpi.com/1996-1944/17/3/701carbonaceous slatechemical erosiontriaxial compressiondiscrete element simulation |
| spellingShingle | Guangwei Xiong Qiunan Chen Yongchao He Zhenghong Chen Xiaocheng Huang Yunpeng Xie Study on the Degradation Effect of Carbonaceous Shale under the Coupling Effect of Chemical Erosion and High Temperature Materials carbonaceous slate chemical erosion triaxial compression discrete element simulation |
| title | Study on the Degradation Effect of Carbonaceous Shale under the Coupling Effect of Chemical Erosion and High Temperature |
| title_full | Study on the Degradation Effect of Carbonaceous Shale under the Coupling Effect of Chemical Erosion and High Temperature |
| title_fullStr | Study on the Degradation Effect of Carbonaceous Shale under the Coupling Effect of Chemical Erosion and High Temperature |
| title_full_unstemmed | Study on the Degradation Effect of Carbonaceous Shale under the Coupling Effect of Chemical Erosion and High Temperature |
| title_short | Study on the Degradation Effect of Carbonaceous Shale under the Coupling Effect of Chemical Erosion and High Temperature |
| title_sort | study on the degradation effect of carbonaceous shale under the coupling effect of chemical erosion and high temperature |
| topic | carbonaceous slate chemical erosion triaxial compression discrete element simulation |
| url | https://www.mdpi.com/1996-1944/17/3/701 |
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