Chemically- and mechanically-mediated influences on rock fractures and their implications on thermomechanical loading cycle

Ki Bok Min, Jonny Rutqvist, Derek Elsworth

Research output: Contribution to conferencePaper

Abstract

A model is presented to represent changes in the mechanical and transport characteristics of fractured rock that result from coupled mechanical and chemical effects. The specific influence is the elevation of dissolution rates on contacting asperities which result in a stress- and temperature-dependent permanent closure. A model representing this pressure-dissolutionlike behavior is adapted to define the threshold and resulting response in terms of fundamental thermodynamic properties of a contacting fracture. These relations are incorporated into a stress-stiffening model of fracture closure to define the stress- and temperature-dependency of aperture loss, and behavior during stress and temperature cycling. These models compare well with laboratory and field experiments, representing both decoupled isobaric and isothermal responses. The model was applied to explore the impact of these responses on heated structures in rock. The result showed a reduction in ultimate induced stresses over the case where chemical effects were not incorporated, with permanent reduction in final stresses after cooling to ambient conditions. Similarly, permeabilities may be reduced over the case where chemical effects are not considered, with a net reduction apparent even after cooling to ambient temperatures. These heretofore neglected effects may have correspondingly a significant impact on the performance of heated structures in rock, such as repositories for the containment of radioactive wastes.

Original languageEnglish (US)
Publication statusPublished - Dec 1 2008
Event42nd U.S. Rock Mechanics - 2nd U.S.-Canada Rock Mechanics Symposium 2008 - San Francisco, CA, United States
Duration: Jun 29 2008Jul 2 2008

Other

Other42nd U.S. Rock Mechanics - 2nd U.S.-Canada Rock Mechanics Symposium 2008
CountryUnited States
CitySan Francisco, CA
Period6/29/087/2/08

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All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics

Cite this

Min, K. B., Rutqvist, J., & Elsworth, D. (2008). Chemically- and mechanically-mediated influences on rock fractures and their implications on thermomechanical loading cycle. Paper presented at 42nd U.S. Rock Mechanics - 2nd U.S.-Canada Rock Mechanics Symposium 2008, San Francisco, CA, United States.