Characterization of fracture roughness and its role in modelling the stress-flow behaviour of fractured rock

Briggins, David Rodney (1992) Characterization of fracture roughness and its role in modelling the stress-flow behaviour of fractured rock. Masters thesis, Memorial University of Newfoundland.

[English] PDF (Migrated (PDF/A Conversion) from original format: (application/pdf)) - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. Download (5MB) [English] PDF - Accepted Version Available under License - The author retains copyright ownership and moral rights in this thesis. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission. (Original Version)

Abstract

The importance of fracture roughness in the mechanical and hydraulic behaviour of fractured rock has long been recognized but quantitative modelling of its effects has proven to be difficult. This study addresses the characterization of fracture roughness and assesses some of the existing stress-flow models that exist in the literature. As part of the study, laboratory stress-flow tests were carried out on a single, natural fracture in a 20 cm diameter granite core. These were followed by injection of an epoxy resin into the fracture plane at a specified normal stress and flow rate. The resin injection experiment enabled direct measurements and characterization of the roughness of both sides of the fracture, contact area, aperture and void space. Statistical analysis of these parameters indicated that the distributions were skewed towards zero and could be approximated reasonably well by a log-normal distribution. All of the stress-flow models examined, including the parallel plate model, were found to have limited application or required simplifying assumptions with respect to fracture roughness. From the results of this study it is clear that fracture flow theory must take into account both sides of the fracture, the variation and spatial distribution of fracture aperture, and the different scales of roughness that exist.

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