Interaction characteristics between rock burst risk region and neighboring fractural plane: a numerical investigation based on moment tensor inversion and Kmeans++ clustering

Traditional rock burst always forms the V-shaped groove in tunnel sidewall, and the interaction characteristics and mechanisms between the original fractural plane and potential V-shaped failure region are not yet clear. We thus carried out the numerical investigation through PFC2D software to explore the interaction features between the above objects. Three sets of post-processing analyses are applied, the moment tensor inversion helps to reveal the quantitative intensity and specific patterns of secondary damage, the events cluster analysis through the Kmeans++ clustering method calibrates the development process of spalling failure at different positions, and the principal stress estimation can predict the extent and maximum depth of the V-shaped groove. Numerical simulations proved that the fractural plane cannot affect the failure process of the intact surrounding rock in left sidewall, and the fractural plane leads to the early appearance of secondary failures in the right sidewall; as the fractural plane moves outward, the size of V-shaped failure region and the dominant mode of secondary failures gradually change; when the fractural plane is outside the potential V-shaped failure zone, the local failure (caused by fractural plane) and spalling failure (started at tunnel free surface) exhibit independent development during majority period of the test.