Special Issue Paper
Fracture aperture reconstruction and determination of hydrological properties: a case study at Draix (French Alps)
Version of Record online: 23 FEB 2011
Copyright © 2011 John Wiley & Sons, Ltd.
Special Issue: Hydrology of Clay Shales and Clayey Sediments
Volume 26, Issue 14, pages 2095–2105, 1 July 2012
How to Cite
Neuville, A., Toussaint, R. and Schmittbuhl, J. (2012), Fracture aperture reconstruction and determination of hydrological properties: a case study at Draix (French Alps). Hydrol. Process., 26: 2095–2105. doi: 10.1002/hyp.7985
- Issue online: 3 JUL 2012
- Version of Record online: 23 FEB 2011
- Manuscript Accepted: 13 DEC 2010
- Manuscript Received: 11 MAR 2010
- aperture reconstruction;
- optical profiler
We propose two techniques for fracture aperture reconstruction. The first one is a correlation technique that estimates the normal aperture or the tangential shift across a discontinuity whose sides present geometrical similarities. The only required material is a pair of appropriately controlled images of each side. Here, the images are maps of the corresponding side topography, obtained from laser profilometry. Assuming a purely normal opening, it is possible, from two corresponding sides of a given discontinuity in a core log, to infer the precise geometry of the in situ aperture. The second technique allows to retrieve the three-dimensional geometry of a sealed discontinuity from non-independent topography measurements of both sides. Both techniques are applied to discontinuities extracted from a core drilled down to 20 m in a fractured marl formation at Draix (French Alps). The probability density functions of the aperture of the sealed and open discontinuities are shown to be Gaussian. At the sample scale, the sealed fracture aperture is self-affine, while the open one shows a cross-over from a self-affine regime at very small scales to an uncorrelated regime at largest scales. After extrapolating those scaling laws at the scale of the whole formation, we discuss when the aperture roughness affects the hydraulic properties of the Draix fractured bedrock. The overall estimated permeability is significant (10−9 − 10−8 m2), consistently with some previous indirect inferences. Copyright © 2011 John Wiley & Sons, Ltd.