Stress Field Comparison in Deep Coal Mines: Roof Cutting Versus Traditional Methods

With the increase of coal mining depth, roadway stability has become an important research topic in safe and efficient mining of coal mines. The traditional methods of the room and pillar mining (RPM) and the gob-side entry retained by filling (GERF) withstand the pressure of roof by coal pillars and dense roadside supports, which leads to the problem of stress concentration. Recently, an innovative gob-side entry retained by roof cutting (GERRC) technology was been widely used in China’s coal production. There are some differences in the stress field in different mining methods. By means of theoretical analysis, numerical simulation and field test, this study explored the distribution characteristics of stress field of three mining methods. The results indicate that the GERRC method cuts off the connection between the roadway roof and the goaf roof, changes the movement of the overlying strata, and reduces the stress of the surrounding rock of the roadway, which belongs to the active pressure-relief technology. The RPM and GERF methods do not change the structure of the surrounding rock, which belongs to the passive pressure-resistance technology, and the surrounding rock of the roadway is significantly affected by the pressure. At the same time, numerical simulation results indicate that the maximum stress in the GERRC method is reduced by 18.1% compared to the RPM method and by 16.1% compared to the GERF method, and the stress concentration area is far away from the roadway. Finally, the numerical simulation results and field monitoring data show good agreement, and the deformation of the surrounding rock can be successfully managed by GERRC technology. The research results provide a guide for the application of GERRC technology in deep coal mines.