Rockburst characteristics and prediction in deep roadways with straight structural planes under dynamic disturbance

To investigate the characteristics of rockburst failure and the intensity levels of rockbursts in deep-buried roadways with straight walls and structural planes, a true-triaxial test was conducted on cubic limestone samples extracted from indoor arched roadways featuring straight walls and structural planes. The failure of the rock mass was monitored in real-time using a miniature camera and acoustic emission techniques. The stress coefficient for the rock mass was defined using Fish language and subsequently imported into FLAC^3D numerical simulation software to predict the rockburst intensity levels of roadways with concealed straight structural planes. The research findings indicate that the straight-wall arch-shaped specimen without exposed straight structural planes experiences rockburst failure, whereas the specimen with exposed straight structural planes undergoes rock slab cracking failure. Furthermore, the extent of damage and the depth of the “V” groove failure zone in the former specimen is greater than that in the latter. The cumulative ringing count and absolute energy of acoustic emissions from the unexposed flat structure test sample exceed those of the exposed straight structure test sample. Notably, the proportion of shear failure in the unexposed straight structure test sample during the entire loading process is significantly lower compared to that of the exposed straight structure sample. The presence of undisclosed straight structural planes leads to variations in the rockburst intensity levels across different sections of the roadway. Specifically, the rockburst intensity level of the side walls containing undisclosed straight structural planes has increased from level 1 to level 2. These research results offer new insights for the prevention and control of rockbursts in underground caverns subjected to high stress and dynamic disturbances.