Shear Failure and Shear Fracturing in Shales


This paper present an experimental study on the shear behavior and the formation of shear fractures in shales. The experimental study is based on triaxial tests on shales sheared at different effective confining stresses. Triaxial tests with different loading conditions have been performed to establish the brittle-to-ductile transition. Based on the results of the tests, it is shown that the brittle-to-ductile transition can be related to the overconsolidation ratio. A relationship between normalized undrained shear strength and overconsolidation ratio is established. In combination with this relationship, a correlation between compressional wave velocity and apparent pre-consolidation stress, which accounts for both mechanical and chemical diagenesis, may be used as a tool to evaluate shear failure and fracturing in shales.

Meeting Name

1st Canada-US Rock Mechanics Symposium - Rock Mechanics Meeting Society's Challenges and Demands (2007: May 27-31, Vancouver, BC, Canada)


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Rock mechanics; Sedimentology; Shale; Shear strength; Stresses; Compressional wave velocities; Confining stresses; Consolidation stresses; Experimental studies; Loading conditions; Over-consolidation ratios; Shear behaviors; Shear failures; Shear fractures; Triaxial tests; Undrained shear strengths; Mechanics

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2007 American Rock Mechanics Association (ARMA), All rights reserved.

Publication Date

01 May 2007

This document is currently not available here.