Longwall top coal caving with gob-side entry retaining is frequently encountered in thick coal seams. Under such geological conditions, significant deformation, support system failure, and the inability to retract supports, caused by intense mining-induced stress disturbances and weak surrounding rock, have become prominent factors hindering safe and efficient coal production. To ensure gob-side entry retaining stability, a combined method integrating pressure relief (PR) and roadside filling support (RFS) is adopted. Through theoretical analysis and numerical simulation, the combination mechanism and pressure relief effect of PR and RFS are analyzed. The results show that PR efficaciously cuts off the suspended roof structure on the goaf side, effectively utilizing the broken expansion effect and supporting effect of the collapsed gangue. Meanwhile, RFS provides high-strength resistance for the roof cutting short-wall beam. The stress distribution of gob-side entry retaining combined pressure relief and roadside filling support (GER-PRRFS) has obvious zoning characteristics. Furthermore, the stress concentration area is greatly transferred to the deep part of coal-rock mass, accompanied by a substantial reduction in the peak stress value, thereby realizing the load-bearing homogenization of the coal-rock mass. Finally, a ‘low-level support - high-level strata pressure relief - upper-level strata load bearing’ method for stability control of GER-PRRFS is proposed. Field tests demonstrates that the deformation of surrounding rock and the disturbance intensity of mining-induced stress are significantly reduced.
Shen et al. (Mon,) studied this question.