JRMGE / Vol 15 / Issue 2
Effect of shear-induced contact area and aperture variations on nonlinear flow behaviors in fractal rock fractures
Changsheng Wang, Richeng Liu, Yujing Jiang, Gang Wang, Hengjie Luan
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a Shandong Key Laboratory of Civil Engineering Disaster Prevention and Mitigation, Shandong University of Science and Technology, Qingdao, 266590, China
b 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, 266590, China
c State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, 221116, China
d School of Engineering, Nagasaki University, Nagasaki, 852-8521, Japan
2023, 15(2): 309-322. doi:10.1016/j.jrmge.2022.04.014
Received: 2022-01-04 / Revised: 2022-03-17 / Accepted: 2022-04-14 / Available online: 2022-05-30
2023, 15(2): 309-322.
doi:10.1016/j.jrmge.2022.04.014
Received: 2022-01-04
Revised: 2022-03-17
Accepted: 2022-04-14
Available online: 2022-05-30
This study experimentally analyzes the nonlinear flow characteristics and channelization of fluid through rough-walled fractures during the shear process using a shear-flow-visualization apparatus. A series of fluid flow and visualization tests is performed on four transparent fracture specimens with various shear displacements of 1 mm, 3 mm, 5 mm, 7 mm and 10 mm under a normal stress of 0.5 MPa. Four granite fractures with different roughnesses are selected and quantified using variogram fractal dimensions. The obtained results show that the critical Reynolds number tends to increase with increasing shear displacement but decrease with increasing roughness of fracture surface. The flow paths are more tortuous at the beginning of shear because of the wide distribution of small contact spots. As the shear displacement continues to increase, preferential flow paths are more distinctly observed due to the decrease in the number of contact spots caused by shear dilation; yet the area of single contacts increases. Based on the experimental results, an empirical mathematical equation is proposed to quantify the critical Reynolds number using the contact area ratio and fractal dimension.
Keywords: Fracture, Shear displacement, Fractal dimension, Nonlinear flow, Contact area, Flow visualization
Article Data
Author(s) Information
Prof. Yujing Jiang
jiang@nagasaki-u.ac.jp
Yujing Jiang is an academician in Engineering Academy of Japan. He obtained his BSc and MSc degrees from Shandong University of Science and Technology (SDUST), China, in 1982 and 1985, respectively, and his PhD from Kyushu University, Japan, in 1993. He is currently the director of the State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology, vice chairman of the Soft-rock Engineering and Deep Disaster Control Sub-society of Chinese Society for Rock Mechanics and Engineering (CSRME). He is also winner of Joint Research Fund for Overseas Natural Science of China. His main research interests include (1) environmental geotechnical engineering, (2) rock mechanics and rock engineering, (3) development and utilization of underground space, (4) remote monitoring forecast and control for geological disaster, (5) mining of deep-sea resources (natural gas hydrate) and control of seabed strata environment, and (6) mine pressure and strata control. He has published 15 books in Chinese and foreign languages and over 300 research papers. He is vice editor of Rock Mechanics and Rock Engineering, and also serves as the editorial board member of several journals, including Journal of Rock Mechanics and Geotechnical Engineering (JRMGE).