Study on spatiotemporal evolution law of surrounding rock stress in deep high-stress soft rock roadways

To address large deformation and support failure in deep, high-stress soft-rock roadways, this study investigates the - 810 m track main roadway of Pansan Coal Mine using fiber Bragg grating three-dimensional stress monitoring and borehole fracture observation, combined with FLAC3D numerical simulations. Results show that the maximum principal stress gradually transfers to the deep surrounding rock with increasing roadway distance, while the shallow rock undergoes continuous unloading, promoting plastic zone expansion and eventual instability. Timely reinforcement of the shallow surrounding rock is critical to forming an integral load-bearing system with the deep rock mass. The spatiotemporal effect of principal stress evolution is identified as the fundamental cause of roadway failure, providing theoretical and practical guidance for deep roadway support design.