Study on the influence law of overlying goaf on the surrounding rock stress field of excavation roadway

In deep coal mining, multi-seam mining is prevalent. Among various mining-induced effects, the stress disturbance imposed by the overlying coal seams on the underlying coal and rock masses is the most intricate, which also constitutes one of the crucial factors triggering compound dynamic disasters at the mining face. In this research, taking the overlying goaf and the underlying excavation roadway in the No.6 Mine of Pingdingshan Tianan Coal. Mining Co., Ltd., as the study object, the UDEC software is employed to simulate the influence of the overlying goaf on the stress redistribution of the wind roadway in the underlying driving face. A comparative analysis is further conducted with the on-site three-dimensional disturbed stress measurement data. The results indicate that the impact of the overlying goaf on the surrounding rock stress of the underlying driving roadway is primarily manifested in the vertical direction, with a relatively minor impact on the horizontal stress. As the increase of the horizontal distance from the overlying mining area, the stress of the left side of the roadway shows an increasing and then decreasing trend, and the stress of the right side of the roadway shows a gradual decrease to a stable trend. Numerical simulation results show that the vertical stress concentration coefficient of the surrounding rock of the excavation roadway increases to a maximum of 1.52, and the horizontal lateral pressure coefficient decreases to a maximum of 0.93, the horizontal influence range of the overlying goaf on the stress of the underlying driving roadway is approximately 136 m. The field stress test results show that the vertical stress concentration coefficient of the roadway surrounding rock surges to 1.74, and the horizontal lateral pressure coefficient diminishes from 1.40 to 0.85, and the horizontal influence range of the overlying goaf is about 141 m. This study can provide a theoretical foundation for the layout of multi-seam mining and disaster prevention and control.