Abstract: In order to study influence of loading stress distribution of surrounding rocks on rockburst characteristics during tangential stress concentration process, rockburst simulation tests were conducted on large class rock-like models under uniform and gradient stress loading by using independently developed gradient and gas-liquid composite loading devices. Then, rockburst characteristics were compared and analyzed from aspects of model burst phenomenon, debris morphology and distribution features. The results show that there are obvious differences in rockburst characteristics between uniform and gradient stress loading. Under uniform stress loading, model rockburst mainly forms flaky and plate-like debris with tensile failure, and ejection distance of debris is relatively short with a smaller rockburst intensity. However, under load of gradient stress, it mainly forms massive debris with shear failure, which has a relatively greater ejection distance and intensity

Key words: uniform stress, gradient stress, strain rockburst, gas-liquid compound, failure characteristics