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| Experimental study on permeability characteristics and its evolution of granite after high temperature |
| XI Baoping1，2，CHENG Zepeng1，HE Shuixin1，YANG Xinxin1，LIU Jie3 |
| (1. College of Mining Engineering，Taiyuan University of Technology，Taiyuan，Shanxi 030024，China；2. Key Laboratory of Insitu Property Improving Mining of Ministry of Education，Taiyuan University of Technology，Taiyuan，Shanxi 030024，China；
3. The 2nd Engineering CO.，LTD of China Railway 12th Bureau Group，Taiyuan，Shanxi 030024，China) |
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Abstract High temperature treatment has a significant effect on the permeability of granite. The permeability of granite after high temperature is closely related to the temperature experienced and the stress state. Using Pressure pulse attenuation method，we studied the permeability of granite after the high temperature(100 ℃–600 ℃) under different stress state. On this basis，we analyzed the macro-mesoscopic physical and mechanical properties of granite with temperature，and the evolution law of granite permeability after high temperature with volume stress，pore pressure and effective stress. The results show that：(1) After high temperature treatment，the permeability of granite increases gradually with the temperature experienced. The permeability of granite increases slightly under 500 ℃，and a step change occurs in the permeability of granite at 500 ℃–600 ℃. (2) After the same high temperature treatment，the permeability of granite shows a decreasing trend with the increase of volume stress，and the decreasing range gradually decreases. Under the same volume stress，the permeability of granite increases with the increase of pore pressure. (3) There is a negative exponential relationship between granite permeability and effective stress after high temperature，and the permeability decreases with the increase of effective stress. (4) The relationship between permeability and temperature and effective stress of granite after high temperature treatment under 600 ℃ was obtained by fitting. The research results can provide theoretical basis and technical support for the construction of hot dry rock geothermal artificial heat storage，and enrich and develop the connotation of high temperature rock mechanics.
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2021, Vol. 40 
