Spatio-temporal Localization of Deformation in Rocks under Quasistatic Uniaxial Loading

Abstract

In this work digital image correlation method is used to study the spatio-temporal strain localization under uniaxial compression of granite samples and uniaxial tension of sylvinite specimens. These experiments showed that the sylvinite tension process realized as two consistently following forms of the spatio-temporal localization: a system of equidistant stationary foci of localized strain and a single stationary localized dissipative structure. Transition from one localization form to another occurs in the vicinity of the stress maximum. Under uniaxial granite compression the deformation process realizes as consistently propagating waves of localized strain on the specimen surface. It is shown that the velocity of the localized strain wave at 6-7 orders of magnitude smaller than the characteristic velocity of the elastic wave propagation in these materials and depends on the magnitude of an applied stress. At the final stage of deformation localized strain waves “gather” to the site of the main crack future exit on the lateral surface of the sample.