• The ultimate pull-out force increases with bonding length in three stages: rapid, slow, and uniform growth.
• A new mechanical model quantifies the reinforcing effect of confining pressure on anchoring force and describes the inverse relationship between radial pressure and plastic zone size.
• Failure crack initiation during pull-out occurs in the order of orifice, bottom, and middle of the hole, with radial pressure inhibiting resin cracking but creating an external crushing zone.
• The synergistic effect between bonding length and radial pressure was validated through industrial tests, ensuring stope roof stability in deep high-stress mines.