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Geomechanics and Engineering Volume 22, Number 5, September10 2020 , pages 375-384 DOI: https://doi.org/10.12989/gae.2020.22.5.375 |
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Analysis of permeability in rock fracture with effective stress at deep depth |
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Hangbok Lee, Tae-Min Oh and Chan Park
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| Abstract | ||
| In this study, the application of conventional cubic law to a deep depth condition was experimentally evaluated. Moreover, a modified equation for estimating the rock permeability at a deep depth was suggested using precise hydraulic tests and an effect analysis according to the vertical stress, pore water pressure and fracture roughness. The experimental apparatus which enabled the generation of high pore water pressure (< 10 MPa) and vertical stress (< 20 MPa) was manufactured, and the surface roughness of a cylindrical rock sample was quantitatively analyzed by means of 3D (three-dimensional) laser scanning. Experimental data of the injected pore water pressure and outflow rate obtained through the hydraulic test were applied to the cubic law equation, which was used to estimate the permeability of rock fracture. The rock permeability was estimated under various pressure (vertical stress and pore water pressure) and geometry (roughness) conditions. Finally, an empirical formula was proposed by considering nonlinear flow behavior; the formula can be applied to evaluations of changes of rock permeability levels in deep underground facility such as nuclear waste disposal repository with high vertical stress and pore water pressure levels. | ||
| Key Words | ||
| deep depth; rock permeability; high vertical stress; high pore water pressure; roughness; nonlinear flow; underground facility; nuclear waste disposal repository | ||
| Address | ||
| Hangbok Lee and Chan Park: Center for Deep Subsurface Research, Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Republic of Korea Tae-Min Oh: Department of Civil and Environmental Engineering, Pusan National University, Busan 46241, Republic of Korea | ||