Study on the Cooperative Control of Surrounding Rock in Roadway Retaining with Gangue Backfilling in Coal Mining Faces

Surrounding rock control of gob-side entry is facing significant technical bottlenecks due to the severe effect of confining pressure in coal mine working face. The implementation of gangue filling technology in goaf area can effectively inhibit the macroscopic fracture and migration of overburden structure induced by deep mining, improve the distribution characteristics of confining pressure under high stress environment, and provide theoretical support for the stability control of gob-side entry in coal mine working face. Combined with field monitoring and mechanical analysis, the dynamic response law of overburden rock under the condition of gangue filling is systematically studied, and the bearing mechanism and instability criterion of surrounding rock of gob-side entry are revealed. According to the engineering characteristics of 15403 fully mechanized mining face in Huayang No.1 Coal Mine, a composite support structure of ' full-section anchor cable support system + three-dimensional support array in roadway + pre-stressed anchor cable reinforcement on coal body side + gangue filling body beside roadway ' was constructed. The coordinated control of bolt pre-tightening force and the combined support technology of retaining wall pillar were implemented simultaneously, and the double protection system of roof anchorage and column support was set up on the goaf side. The engineering application shows that the zoning differential cooperative control scheme can effectively maintain the stable state of the narrow roadway retaining structure of the gangue filling body.