Shear behaviour of fractured rock as a function of size and shear displacement

Giwelli, A. A., Sakaguchi, K., Gumati, A. and Matsuki, K. (2014) Shear behaviour of fractured rock as a function of size and shear displacement. Geomechanics and Geoengineering, 9 4: 253-264. doi:10.1080/17486025.2014.884728

Author Giwelli, A. A.
Sakaguchi, K.
Gumati, A.
Matsuki, K.
Title Shear behaviour of fractured rock as a function of size and shear displacement
Journal name Geomechanics and Geoengineering   Check publisher's open access policy
ISSN 1748-6025
Publication date 2014
Year available 2014
Sub-type Article (original research)
DOI 10.1080/17486025.2014.884728
Open Access Status
Volume 9
Issue 4
Start page 253
End page 264
Total pages 12
Place of publication Abingdon, Oxfordshire, United Kingdom
Publisher Taylor & Francis
Collection year 2015
Language eng
Abstract This paper presents laboratory results regarding the shear behaviour of an artificial tensile fracture generated in granite. We used a direct shear rig to test fractures of different sizes (from 100 mm to 200 mm) under various shear displacements up to 20 mm and cyclic shear stresses with constant normal stress of 10 MPa. To determine the evolution of surface damage and aperture during shear, cyclic loading was performed at designated shear displacements. These changes in the surfaces topography were measured with a laser profilometer 'non-contact surface profile measurement system'. In addition, changes were also measured directly by using pressure-sensitive film.The results showed that the standard deviation (SD) of the initial aperture of the sheared fracture significantly increases with both shear displacement and size, which result in an increase in the non-linearity of the closure curve (since the matedness of the fracture surfaces decreases with shear displacement). Therefore, we concluded that shear dilation is not only governed by the surfaces sliding over each other, but is also strongly influenced by the non-linearity of closure with shear displacement. Furthermore, while the shear stiffness of the fracture during the initial stage decreases with fracture size, it increases with fracture size in the residual stage. This can be attributed to the fact that only small asperities with short wavelengths were mainly damaged by shearing. Moreover the result showed that the damaged zones enlarge and localise with shear displacement, and eventually tend to form perpendicular to the shear displacement.
Keyword Shear behaviour
Shear displacement
Shear dilation
Asperity damage
Fracture size
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Chemical Engineering Publications
Official 2015 Collection
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