Strength and failure characteristics of brittle jointed rock-like specimens under uniaxial compression: Digital speckle technology and a particle mechanics approach

The strength and failure characteristics of most natural rock mass are influenced by discontinues such as fissures, joints, and weak surfaces. In the present study, the strength and failure behavior of ubiquitous-joint rock-like specimens under uniaxial loading have been investigated by DIC (digital image correlation) and discrete element numerical method (PFC2D). The results are obtained. Firstly, the UCSJ of specimens with gamma = 15 degrees or 30 degrees shows similar tendency while alpha goes from 0 degrees to 75 degrees. With gamma = 45 degrees or 60 degrees, the UCSJ of specimens increases when alpha goes from 0 degrees to 30 degrees and decreases after alpha goes beyond 30 degrees. With gamma = 75 degrees, the peak UCSJ value is reached when alpha = 0 degrees. The UCSJ value shows an increasing trend when alpha goes from 60 degrees to 75 degrees. Secondly, the ubiquitous-joint specimens present different failure modes for various levels of alpha and gamma(beta-alpha). Based on the experimental results, the failure mode of ubiquitous-joint specimens can be classified into three categories: stepped path failure, failure through parallel plane, and failure through cross plane. (C) 2018 Published by Elsevier B.V. on behalf of China University of Mining & Technology. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).