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Thermal-mechanical coupled effect on fracture mechanism and plastic characteristics of sandstone |
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| Authors: | Zuo JianPing Xie HePing Zhou HongWei Peng SuPing |
| Affiliation: | 1. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083, China;Institute of Rock Mechanics and Fractals, China University of Mining and Technology, Beijing 100083, China 2. Sichuan University, Chengdu 610065, China;Institute of Rock Mechanics and Fractals, China University of Mining and Technology, Beijing 100083, China 3. State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083, China |
| Abstract: | Scanning electronic microscopy (SEM) was employed to investigate fractographs of sandstone in mine roof strata under thermal-mechanical coupled effect. Based on the evolution of sandstone surface morphology in the failure process and fractography, the fracture mechanism was studied and classified under meso and micro scales, respectively. The differences between fractographs under different temperatures were examined in detail. Under high temperature, fatigue fracture and plastic deformation occurred in the fracture surface. Therefore, the temperature was manifested by these phenomena to influence strongly on micro failure mechanism of sandstone. In addition, the failure mechanism would transit from brittle failure mechanism at low temperature to coupled brittle-ductile failure mechanism at high temperature. The variation of sandstone strength under different temperature can be attributed to the occurrence of plastic deformation, fatigue fracture, and microcracking. The fatigue striations in the fracture surfaces under high temperature may be interpreted as micro fold. And the coupled effect of temperature and tensile stress may be another formation mechanism of micro fold in geology. |
| Keywords: | sandstone thermal-mechanical coupled effects fractograph plastic deformation SEM micro fold |
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