• Introduces a novel composite stress arch model that more accurately captures stress evolution under repeated mining of close-distance coal seams compared to traditional single arch theories.
• Reveals the gradual transformation of a single stress arch into a composite structure, reflecting increasing stress distribution complexity during repeated mining.
• Determines that the optimal stop-mining coal pillar width for the Longfeng Coal Mine is between 65 and 70 m, based on numerical simulations and field monitoring.
• Establishes a coupling relationship between composite arch evolution and abutment pressure distribution, providing a theoretical basis for coal pillar design and stope stability enhancement.