HR: 1340h
AN: H23G-1705    [Abstracts]
TI: Characterization of fracture aperture for groundwater flow and transport
AU: * Sawada, A
EM: sawada.atsushi@jaea.go.jp
AF: Japan Atomic Energy Agency, 4-33 Muramatsu Tokai-mura, Ibaraki, 319-1194, Japan
AU: Sato, H
EM: sato.hisashi@jaea.go.jp
AF: Japan Atomic Energy Agency, 4-33 Muramatsu Tokai-mura, Ibaraki, 319-1194, Japan
AU: Tetsu, K
EM: tetsu.keiichi@jaea.go.jp
AF: Inspection Development Company Ltd, 4-33 Muramatsu Tokai-mura, Ibaraki, 319-1194, Japan
AU: Sakamoto, K
EM: sakamoto.kazuhiko@jaea.go.jp
AF: Inspection Development Company Ltd, 4-33 Muramatsu Tokai-mura, Ibaraki, 319-1194, Japan
AB: This paper presents experiments and numerical analyses of flow and transport carried out on natural fractures and transparent replica of fractures. The purpose of this study was to improve the understanding of the role of heterogeneous aperture patterns on channelization of groundwater flow and dispersion in solute transport. The research proceeded as follows: First, a precision plane grinder was applied perpendicular to the fracture plane to characterize the aperture distribution on a natural fracture with 1 mm of increment size. Although both time and labor were intensive, this approach provided a detailed, three dimensional picture of the pattern of fracture aperture. This information was analyzed to provide quantitative measures for the fracture aperture distribution, including JRC (Joint Roughness Coefficient) and fracture contact area ratio. These parameters were used to develop numerical models with corresponding synthetic aperture patterns. The transparent fracture replica and numerical models were then used to study how transport is affected by the aperture spatial pattern. In the transparent replica, transmitted light intensity measured by a CCD camera was used to image channeling and dispersion due to the fracture aperture spatial pattern. The CCD image data was analyzed to obtain the quantitative fracture aperture and tracer concentration data according to Lambert-Beerfs law. The experimental results were analyzed using the numerical models. Comparison of the numerical models to the transparent replica provided information about the nature of channeling and dispersion due to aperture spatial patterns. These results support to develop a methodology for defining representative fracture aperture of a simplified parallel fracture model for flow and transport in heterogeneous fractures for contaminant transport analysis.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1847 Modeling
SC: Hydrology [H]
MN: 2007 Fall Meeting