Brittle Failure Mechanisms of Rock.

Abstract

At high compressive stress, microcracks in rock lengthen in the stress direction. Slender columns of unbroken material are left between the cracks; SEM measurements of length/width ratio of these columns suggest that some could have buckled under the loads applied in the experiments, and thus been the source of the sudden instability at faulting. Thermal expansion of rocks was measured under high pressure for the first time: below some critical pressure, thermal cracking occurred, due both to thermal gradients and anisotropy in thermal expansion of the minerals. Observed thermal expansion at high pressure was close to Walsh's theoretical bounds; thus, thermal expansion of rocks under pressure can be calculated with sufficient accuracy for many applications.

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Document Details

Document Type
Technical Report
Publication Date
Apr 10, 1979
Accession Number
ADA067838

Entities

People

  • W. F. Brace

Organizations

  • Massachusetts Institute of Technology

Tags

DTIC Thesaurus Topics

  • Abstracts
  • Buckling
  • Electron Microscopes
  • Failure Mode And Effect Analysis
  • High Pressure
  • High Temperature
  • Instability
  • Materials
  • Measurement
  • Mechanics
  • Military Research
  • Planetary Sciences
  • Rock Mechanics
  • Scanning Electron Microscopes
  • Stresses
  • Thermal Expansion
  • Thermal Stresses

Fields of Study

  • Engineering

Readers

  • Materials Science (Mechanical Engineering).
  • Structural Dynamics.
  • Thermal Physics or Thermal Science.