Deformation and damage mechanisms of Y-intersecting jointed rocks under uniaxial compression

• Failure modes of Y-intersecting jointed rocks transition from overall failure to wedge block ejection and shear failure as primary joint dip angle increases. • A failure mode identification model using thresholds for crack dip angle, uniaxial compressive strength, and energy core zone proportion achieves 93.3% accuracy. • Acoustic emission b-value and shear crack ratio exhibit distinct patterns in different failure modes, with sharp changes in high-stress phases for overall and wedge block ejection modes. • Joint slip predominantly occurs during the failure instability phase (>0.8σc) in overall and wedge block ejection modes, providing critical insights for stability monitoring.