Deformation mechanism of gob‐side entry at top coal caving mining face: A numerical study

Abstract

To investigate the significant deformation of the surrounding rock within the dynamic pressure zone of the gateroad, this study utilized the tailgate of the 1506 longwall face in Anyang Coal Mine as the engineering context. A combined approach of field measurement and numerical analysis was employed to explore the deformation and failure mechanisms of the surrounding rock under dynamic pressure. The findings indicate that before the exploitation of the 1506 longwall face, there was a notable reduction in stress across the floor and immediate roof, with minimal stress concentration observed in the coal pillar and the entity rib side. The plastic zone surrounding the tailgate was limited, suggesting a high degree of stability in the entry's surrounding rock. However, during the extraction of the 1506 longwall face, the tailgate, extending 60 m ahead of the working face, was subjected to dynamic pressure, leading to a marked increase in stress within the floor, coal pillar, and immediate roof. Stress concentration was more pronounced on the entity rib side than on the pillar rib side. This resulted in significant fissuring and severe deformation of the entry's surrounding rock. The primary failure mechanism involved damage to both the roof and floor corners, with the severity of damage escalating alongside the stress in the surrounding rock. This culminated in the failure of roof corner bolts and anchor cables, thereby compromising the stability of the entry within the dynamic pressure zone.