Damage and failure characteristics of rock similar materials with pre-existing cracks

In order to further study the damage and failure mechanism for rock similar materials, this study investigated the mechanical properties and failure characteristics, law of damage space development, and damage evolution characteristics for rock similar materials with pre-existing cracks of varying length under uniaxial compression load. The equipment used in this study is the self-developed YYW-II strain controlled unconfined compression apparatus and the PCIE-8 acoustic emission monitoring system. Results show that, as the length of pre-existing crack increases: (1) the peak and residual strength reduces, and the peak axial strain and the strain during the initial compression phase increases; (2) the major failure mode is changed from shear failure to tensile failure along a vertical plane that passes the middle of the pre-existing crack; (3) The damage increases during the stable and accelerated development stage, and the effect of the pre-existing cracks is more during the accelerated development stage than the stable development stage.