Size effects in fracture of rock

Joseph F. Labuz, Luigi Biolzi

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The fracture of rock is influenced by the development of an intrinsic process zone in the form of a localized region of microcracking. This zone has a fundamental importance for defining the system behavior in terms of the post-peak instability and in terms of material strength such that size effects appear. This paper illustrates the change in the load-displacement response and presents evidence of the process-zone development with varying specimen size. It is demonstrated that fracture problems do not require geometric or material nonlinearity to produce instability. The size of a structure that fails by fracture is an important factor. Furthermore, experiments suggest that an intrinsic zone develops in rock as a material characteristic. Because of this intrinsic length, two competing factors define the nominal strength-the positive contribution of the process zone and the depleting aspects of the undamaged volume, that is, the size.

Original languageEnglish (US)
Title of host publicationVail Rocks 1999 - 37th U.S. Symposium on Rock Mechanics (USRMS)
Editors Kranz, Smeallie, Scott, Amadei
PublisherAmerican Rock Mechanics Association (ARMA)
Number of pages7
ISBN (Print)9058090523, 9789058090522
StatePublished - 1999
Event37th U.S. Symposium on Rock Mechanics, Vail Rocks 1999 - Vail, United States
Duration: Jun 7 1999Jun 9 1999

Publication series

NameVail Rocks 1999 - 37th U.S. Symposium on Rock Mechanics (USRMS)


Other37th U.S. Symposium on Rock Mechanics, Vail Rocks 1999
CountryUnited States

Bibliographical note

Funding Information:
Partial support was provided by the National Science Foundation Grant Number CMS-9532061 and the North Atlantic Treaty Organization Collaborative Research Grant Number 950695.

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