Shear induced fluid flow path evolution in rough-wall fractures: A particle image velocimetry examination

Journal of Hydrology, vol. 610, pp. 127793

Abstract

Rough-walled fractures in rock masses, as preferential pathways, largely influence fluid flow, solute and energy transport. Previous studies indicate that fracture aperture fields could be significantly modified due to shear displacement along fractures. We report experimental observations and quantitative analyses of flow path evolution within a single fracture, induced by shear displacement. Particle image velocimetry and refractive index matching techniques were utilized to determine fluid velocity fields inside a transparent 3D-printed shear-able rough fracture. Our analysis indicate that aperture variability and correlation length increase with the increasing shear displacement, and they are the two key parameters, which govern the increases in velocity variability, velocity longitudinal correlation length, streamline tortuosity, and variability of streamline spacing. The increase in aperture heterogeneity significantly impacts fluid flow behaviors, whilst changes in aperture correlation length further refine these impacts. To our best knowledge, our study is the first direct measurements of fluid velocity fields and provides insights into the impact of fracture shear on flow behavior.

Authors 5

1. Isamu Naets

   ETH Zurich · Institute of Geophysics

   Affiliation as printed

   Geothermal Energy and Geofluids Group, Institute of Geophysics, ETH Zurich, Sonneggstrasse 5, Zurich 8092, Switzerland

2. Mehrdad Ahkami Aachen Department of Engineering Geology and Hydrogeology

   RWTH Aachen University

   Affiliation as printed

   Department of Engineering Geology and Hydrogeology, RWTH Aachen University, Lochnerstraße 4-20, Aachen 52056, Germany

3. Po-Wei Huang

   ETH Zurich · Institute of Geophysics

   Affiliation as printed

   Geothermal Energy and Geofluids Group, Institute of Geophysics, ETH Zurich, Sonneggstrasse 5, Zurich 8092, Switzerland

4. Martin O. Saar

   University of Minnesota · ETH Zurich · Institute of Geophysics

   Affiliation as printed

   Department of Earth and Environmental Sciences, University of Minnesota, 116 Church St SE, Minneapolis, MN 55455, United States

   Geothermal Energy and Geofluids Group, Institute of Geophysics, ETH Zurich, Sonneggstrasse 5, Zurich 8092, Switzerland

5. Xiang-Zhao Kong corresponding

   ETH Zurich · Institute of Geophysics

   Affiliation as printed

   Geothermal Energy and Geofluids Group, Institute of Geophysics, ETH Zurich, Sonneggstrasse 5, Zurich 8092, Switzerland