Effect of sample size on the fluid flow through a single fractured granitoid
Most of deep geological engineered structures, such as rock caverns, nuclear waste disposal repositories, metro rail tunnels, multi-layer underground parking, are constructed within hard crystalline rocks because of their high quality and low matrix permeability. In such rocks, fluid flows mainly th...
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| Format: | Article |
| Language: | English |
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Elsevier
2016-06-01
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| Series: | Journal of Rock Mechanics and Geotechnical Engineering |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674775516000238 |
| _version_ | 1818253946698858496 |
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| author | Kunal Kumar Singh Devendra Narain Singh Ranjith Pathegama Gamage |
| author_facet | Kunal Kumar Singh Devendra Narain Singh Ranjith Pathegama Gamage |
| author_sort | Kunal Kumar Singh |
| collection | DOAJ |
| description | Most of deep geological engineered structures, such as rock caverns, nuclear waste disposal repositories, metro rail tunnels, multi-layer underground parking, are constructed within hard crystalline rocks because of their high quality and low matrix permeability. In such rocks, fluid flows mainly through fractures. Quantification of fractures along with the behavior of the fluid flow through them, at different scales, becomes quite important. Earlier studies have revealed the influence of sample size on the confining stress–permeability relationship and it has been demonstrated that permeability of the fractured rock mass decreases with an increase in sample size. However, most of the researchers have employed numerical simulations to model fluid flow through the fracture/fracture network, or laboratory investigations on intact rock samples with diameter ranging between 38 mm and 45 cm and the diameter-to-length ratio of 1:2 using different experimental methods. Also, the confining stress, σ3, has been considered to be less than 30 MPa and the effect of fracture roughness has been ignored. In the present study, an extension of the previous studies on “laboratory simulation of flow through single fractured granite” was conducted, in which consistent fluid flow experiments were performed on cylindrical samples of granitoids of two different sizes (38 mm and 54 mm in diameters), containing a “rough walled single fracture”. These experiments were performed under varied confining pressure (σ3 = 5–40 MPa), fluid pressure (fp ≤ 25 MPa), and fracture roughness. The results indicate that a nonlinear relationship exists between the discharge, Q, and the effective confining pressure, σeff., and Q decreases with an increase in σeff.. Also, the effects of sample size and fracture roughness do not persist when σeff. ≥ 20 MPa. It is expected that such a study will be quite useful in correlating and extrapolating the laboratory scale investigations to in-situ scale and further improving theoretical/numerical models associated with fluid flow through rock masses. |
| first_indexed | 2024-12-12T16:48:09Z |
| format | Article |
| id | doaj.art-f5af17b50e0d49c489e6e941cd7737c9 |
| institution | Directory Open Access Journal |
| issn | 1674-7755 |
| language | English |
| last_indexed | 2024-12-12T16:48:09Z |
| publishDate | 2016-06-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Rock Mechanics and Geotechnical Engineering |
| spelling | doaj.art-f5af17b50e0d49c489e6e941cd7737c92022-12-22T00:18:25ZengElsevierJournal of Rock Mechanics and Geotechnical Engineering1674-77552016-06-018332934010.1016/j.jrmge.2015.12.004Effect of sample size on the fluid flow through a single fractured granitoidKunal Kumar Singh0Devendra Narain Singh1Ranjith Pathegama Gamage2Geohazards and Engineering Geology Division, Geological Survey of India, Bandlaguda, Hyderabad, 500068, IndiaGeotechnical Engineering Division, Department of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, IndiaDepartment of Civil Engineering, Monash University, Clayton, Melbourne, Vic 3800, AustraliaMost of deep geological engineered structures, such as rock caverns, nuclear waste disposal repositories, metro rail tunnels, multi-layer underground parking, are constructed within hard crystalline rocks because of their high quality and low matrix permeability. In such rocks, fluid flows mainly through fractures. Quantification of fractures along with the behavior of the fluid flow through them, at different scales, becomes quite important. Earlier studies have revealed the influence of sample size on the confining stress–permeability relationship and it has been demonstrated that permeability of the fractured rock mass decreases with an increase in sample size. However, most of the researchers have employed numerical simulations to model fluid flow through the fracture/fracture network, or laboratory investigations on intact rock samples with diameter ranging between 38 mm and 45 cm and the diameter-to-length ratio of 1:2 using different experimental methods. Also, the confining stress, σ3, has been considered to be less than 30 MPa and the effect of fracture roughness has been ignored. In the present study, an extension of the previous studies on “laboratory simulation of flow through single fractured granite” was conducted, in which consistent fluid flow experiments were performed on cylindrical samples of granitoids of two different sizes (38 mm and 54 mm in diameters), containing a “rough walled single fracture”. These experiments were performed under varied confining pressure (σ3 = 5–40 MPa), fluid pressure (fp ≤ 25 MPa), and fracture roughness. The results indicate that a nonlinear relationship exists between the discharge, Q, and the effective confining pressure, σeff., and Q decreases with an increase in σeff.. Also, the effects of sample size and fracture roughness do not persist when σeff. ≥ 20 MPa. It is expected that such a study will be quite useful in correlating and extrapolating the laboratory scale investigations to in-situ scale and further improving theoretical/numerical models associated with fluid flow through rock masses.http://www.sciencedirect.com/science/article/pii/S1674775516000238Rock massSingle fractureFluid flowSample sizeSize effectFracture roughness |
| spellingShingle | Kunal Kumar Singh Devendra Narain Singh Ranjith Pathegama Gamage Effect of sample size on the fluid flow through a single fractured granitoid Journal of Rock Mechanics and Geotechnical Engineering Rock mass Single fracture Fluid flow Sample size Size effect Fracture roughness |
| title | Effect of sample size on the fluid flow through a single fractured granitoid |
| title_full | Effect of sample size on the fluid flow through a single fractured granitoid |
| title_fullStr | Effect of sample size on the fluid flow through a single fractured granitoid |
| title_full_unstemmed | Effect of sample size on the fluid flow through a single fractured granitoid |
| title_short | Effect of sample size on the fluid flow through a single fractured granitoid |
| title_sort | effect of sample size on the fluid flow through a single fractured granitoid |
| topic | Rock mass Single fracture Fluid flow Sample size Size effect Fracture roughness |
| url | http://www.sciencedirect.com/science/article/pii/S1674775516000238 |
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