Cooperative load-carrying mechanism and control technology of the gob-side entry retaining by roof cutting and goaf filling

Abstract

The deep mining industry commonly encounters significant challenges, including large displacements of the roof in the gob-side entry retaining, and large deformations and failures of the filling body, which seriously compromise the structural safety and reliability of mines. In this study, we focus on a specific engineering case of the 8318 working face from the Xinzhou coal mine, employing the methodology of roof cutting for pressure relief and goaf filling with gangue reinforcement. Through a comprehensive approach involving numerical analysis, theoretical derivation, and experimental validation, the key parameters of the gob-side entry retaining by roof cutting, and the cooperative load-carrying mechanism of gangue reinforcement in gob-side entry retaining by cutting roof were systematically investigated. The numerical simulations and underground mine pressure monitoring data demonstrated that the optimum roof cutting height is 10 m at an optimum roof cutting angle of 8°. The proposed cooperative load-carrying technology of gob-side entry retaining by roof cutting significantly reduced the peak vertical stresses in the centre of the roof and the filling body by 22.6% and 43.4%, respectively. Furthermore, individual pillar stress levels showed notable reductions, with the maximum working stress and average stress decreasing by 34.2% and 47.8%, respectively. The practical implementation of our study offers valuable guidance in the control of surrounding rock in deep mining, thereby contributing significantly to the advancement in the field of surrounding rock support control.