Abstract:
Addressing the technical challenges of severe deformation and maintenance difficulties in gob-side roadways with retained pillars under hard roof and thin coal seam conditions during mining-excavation interaction at Binhu Coal Mine, this study employs integrated theoretical analysis, numerical simulation, and field experiments to investigate the movement characteristics of the adjacent goaf-side overlying strata, the morphology of the caving structure, and the induced roadway instability mechanism. Key parameters for roof-cutting pressure relief and roadway protection were optimized and applied in engineering practice. The research indicates that two dominant key strata exist within the overburden of the 16# coal seam. Their structural characteristics and mechanical behavior govern the movement patterns and caving structure morphology of the adjacent strata. The dynamic evolution (formation, movement, and caving) of the lateral suspended roof in this zone subjects the roadway surrounding rock to significant multiple dynamic load impacts and high static stress, substantially increasing the risk of roadway instability and failure. Using the maximum principal stress deviatoric as the evaluation indicator, the optimal roof-cutting height and angle were theoretically determined as 16m and 10°, respectively. Field tests further optimized the blasting parameters, establishing a spacing of 2m for deep boreholes and 1m for shallow boreholes. Additionally, a comprehensive support system comprising a primary "bolt-mesh-cable-belt" support combined with temporary reinforcement using "unit hydraulic props" was proposed to enhance the load-bearing capacity of the surrounding rock. Ground pressure monitoring confirmed that roadway deformation was effectively controlled, achieving a self-stabilized state approximately 140m behind the working face. This validates the effectiveness of the roof-cutting pressure relief technology in resolving the maintenance challenges of gob-side roadways under thin coal seam and hard roof conditions.