Rock and Soil Mechanics ›› 2020, Vol. 41 ›› Issue (5): 1750-1760.doi: 10.16285/j.rsm.2019.5813

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Simulations of temperature effects on seepage and deformation of coal micro- structure based on 3D CT reconstruction

WANG Gang1, 2, QIN Xiang-jie2, JIANG Cheng-hao2, ZHANG Zhen-yu3   

  1. 1. State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, Shandong University of Science and Technology, Qingdao, Shandong 266590, China 2. College of Safety and Environmental Engineering, Shandong University of Science and Technology, Qingdao, Shandong 266590, China 3. College of Resources and Environmental Sciences, Chongqing University, Chongqing 400044, China
  • Online:2020-05-27 Published:2020-10-13
  • About author:WANG Gang,male, born in 1984, PhD, Professor, PhD Supervisor, mainly engaged in teaching and research on mine general disaster prediction and prevention.
  • Supported by:
    the National Key Research and Development Program of China (2017YFC0805201), the National Natural Science Foundation of China (51674158,51934004,51974176), the Key Basic Projects of Shandong Province Natural Science Foundation (ZR2018ZA0602) and the Special Funds for Taishan Scholar Project (TS20190935).

Abstract: In order to investigate the influence of temperature in deep coal mining area on coal seepage and pore fracture structure deformation, 3D CT reconstruction technology and ANSYS were used to simulate the process of conjugate heat transfer and thermal deformation of coal microstructure respectively. The conjugate heat transfer simulation results show that water was initially injected into the 80℃ coal wall at 20℃ was heated to 37.13℃ when it flows out. The temperature of the coal gradually decreases along the wall facing the fluid center. Pore fracture structure has an important influence on the velocity and the temperature of the flow along the flow direction. When the connected cross-section porosity is large, the flow speed is slow, the fluid heats up quickly, and the solid temperature decreases. On the other hand, when the connected cross section porosity is small, the flow speed is fast, the fluid temperature rises slowly, and the solid temperature rises. The thermal deformation simulation results show that the deformation is proportional to the distance from the constraint surface. When the deformation near the constraint surface is small, and the direction is pointed to the pore fracture space. While if the deformation at a place that is far away from the constraint surface is large, the deformation direction is diverging outward. Moreover, the existence of the cracks will increase the deformation, the deformation difference between the different pore or crack structures will also increases with the increasing temperature.

Key words: coal, 3D CT reconstruction, conjugate heat transfer, cross-section connected porosity, thermal deformation