Fluid Flow Behavior of Sheared Rough Fractures Subjected to Different Stress State
The hydraulic properties of fractures are greatly affected by the stress. Knowing the fluid flow behavior of fractures is of great importance to underground engineering construction and environmental safety. The main purpose of this paper is to study the fluid flow characteristics of rough fractures...
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MDPI AG
2021-09-01
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author | Min Wang Qifeng Guo Pengfei Shan Yakun Tian Bing Dai |
author_facet | Min Wang Qifeng Guo Pengfei Shan Yakun Tian Bing Dai |
author_sort | Min Wang |
collection | DOAJ |
description | The hydraulic properties of fractures are greatly affected by the stress. Knowing the fluid flow behavior of fractures is of great importance to underground engineering construction and environmental safety. The main purpose of this paper is to study the fluid flow characteristics of rough fractures under different stress states. First, rough fracture surfaces were generated by using the corrected successive random addition (SRA) algorithm. Then, the sheared fracture models subjected to different stress condition were obtained under the boundary condition of constant normal stiffness (CNS). Finally, the hydraulic characteristics of the three-dimensional rough rock fractures were analyzed by numerically solving the full Navier–Stokes equation. It has been found that (1) the aperture of fractures all obeys the Gaussian distribution. The dilatancy effect is gradually obvious and aperture becomes larger with the increase of shear displacement. (2) When the initial normal stress increases, the contact area of fracture becomes larger and the reverse flow can be observed around the contact area. (3) The relationship between hydraulic gradient and flowrate exhibits nonlinearity which can be described by the Forchheimer’s law. The linear coefficient <i>a</i> and the nonlinear coefficient <i>b</i> gradually decrease with the increase of shear displacement and finally stabilize. The values of <i>a</i> and <i>b</i> are reduced by 1–2 and 1–3 orders of magnitude respectively during the shear. The critical Reynolds number increases with the increase of shear displacement and decrease as the initial normal stress increases. |
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language | English |
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publishDate | 2021-09-01 |
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spelling | doaj.art-2e573da3ccba49389607dc9cf3737d572023-11-22T12:35:10ZengMDPI AGCrystals2073-43522021-09-01119105510.3390/cryst11091055Fluid Flow Behavior of Sheared Rough Fractures Subjected to Different Stress StateMin Wang0Qifeng Guo1Pengfei Shan2Yakun Tian3Bing Dai4School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaSchool of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaState Key Laboratory of Coal Resources in Western China, Xi’an University of Science and Technology, Xi’an 710054, ChinaSchool of Resource Environment and Safety Engineering, University of South China, Hengyang 421001, ChinaSchool of Resource Environment and Safety Engineering, University of South China, Hengyang 421001, ChinaThe hydraulic properties of fractures are greatly affected by the stress. Knowing the fluid flow behavior of fractures is of great importance to underground engineering construction and environmental safety. The main purpose of this paper is to study the fluid flow characteristics of rough fractures under different stress states. First, rough fracture surfaces were generated by using the corrected successive random addition (SRA) algorithm. Then, the sheared fracture models subjected to different stress condition were obtained under the boundary condition of constant normal stiffness (CNS). Finally, the hydraulic characteristics of the three-dimensional rough rock fractures were analyzed by numerically solving the full Navier–Stokes equation. It has been found that (1) the aperture of fractures all obeys the Gaussian distribution. The dilatancy effect is gradually obvious and aperture becomes larger with the increase of shear displacement. (2) When the initial normal stress increases, the contact area of fracture becomes larger and the reverse flow can be observed around the contact area. (3) The relationship between hydraulic gradient and flowrate exhibits nonlinearity which can be described by the Forchheimer’s law. The linear coefficient <i>a</i> and the nonlinear coefficient <i>b</i> gradually decrease with the increase of shear displacement and finally stabilize. The values of <i>a</i> and <i>b</i> are reduced by 1–2 and 1–3 orders of magnitude respectively during the shear. The critical Reynolds number increases with the increase of shear displacement and decrease as the initial normal stress increases.https://www.mdpi.com/2073-4352/11/9/1055rough fracturestress stateCNS boundary conditionflow characteristics |
spellingShingle | Min Wang Qifeng Guo Pengfei Shan Yakun Tian Bing Dai Fluid Flow Behavior of Sheared Rough Fractures Subjected to Different Stress State Crystals rough fracture stress state CNS boundary condition flow characteristics |
title | Fluid Flow Behavior of Sheared Rough Fractures Subjected to Different Stress State |
title_full | Fluid Flow Behavior of Sheared Rough Fractures Subjected to Different Stress State |
title_fullStr | Fluid Flow Behavior of Sheared Rough Fractures Subjected to Different Stress State |
title_full_unstemmed | Fluid Flow Behavior of Sheared Rough Fractures Subjected to Different Stress State |
title_short | Fluid Flow Behavior of Sheared Rough Fractures Subjected to Different Stress State |
title_sort | fluid flow behavior of sheared rough fractures subjected to different stress state |
topic | rough fracture stress state CNS boundary condition flow characteristics |
url | https://www.mdpi.com/2073-4352/11/9/1055 |
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