Experimental Investigation on Failure Characteristics of Pre-Holed Jointed Rock Mass Assisted with AE and DIC

For jointed rock mass with anisotropy and discontinuity, the structure of the surrounding rock is constantly developing and changing during tunnel excavation. It is difficult to reasonably predict localized deformation of jointed rock mass by using the existing rock mechanics theory. In this paper, the failure characteristic of pre-holed jointed rock mass with three joint angles is experimentally investigated by adopting the digital image correlation and acoustic emission methods. To avoid the influence of measurement error on Digital Image Correlation (DIC) from discontinuous deformation, parametric studies and an optimized algorithm are also included in DIC tests. Results indicate that the perpendicular-jointed condition (0° joints) is the most dangerous situation because of its comparatively lower strength and brittle failure mode with a shift energy release. For rocks with different jointed angles, localized deformation emerges after the material enters the plasticity. Significant localization occurs after the failure with cracks surrounding the center hole and pre-existing joints.