Antonio Bobet

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COUPLED FLOW AND STRESS-INDUCED SLIP ON
FRICTIONAL DISCONTINUITIES
Antonio Bobet Purdue University
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OUTLINE Objectives Motivation and
Background Experiments proposed Conclusions
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Determination of mechanisms that produce onset
of slip on a frictional discontinuity
Determination of conditions necessary for slip
rupture Quantification of pore pressure
response during slip coupled flow and
mechanics Assessment of coupled
flow-deformation effects of large scale
discontinuities under large stresses
Estimation of scale effects comparison between
laboratory and DUSEL experiments
Evaluation of theoretical fracture mechanics
framework and quantification and modeling
of progressive slip
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Laboratory Small - scale Tests
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(No Transcript)
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Induce slip by Changing stress field
through excavation of additional drifts
Injection of fluid inside discontinuity
Induce flow by Injection of fluid in the
discontinuity parallel or at an angle
with direction of paleoslip. Generation of
excess pore pressures by slip. Continuous
Behavior Monitoring Upscale Fracture Mechanics
Theories (mode II)
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Pressure boring
Monitoring boring
Pressure transducers
Acoustic emission and geophysical sensors
Large-scale frictional discontinuity, e.g. shear
zone
Conceptual experiment setup
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• CONCLUSIONS
• Mode II propagation/sliding are important in
  rock mechanics
• Laboratory experiments show
• critical energy release rate and
• critical displacement are not material
  properties
• Large-scale tests needed DUSEL
• Experiments can be carried out at many scales
• Long-term experiments are possible
• Preliminary work needed
• stress field at DUSEL site, including pore
  pressures.
• rock mass properties and behavior at the test
  site.
• identification and characterization of
  suitable
• frictional discontinuities fault or shear
  zone.
• frictional strength and permeability of target
  discontinuities.