Study on the instability response mechanism and control measures for the key block undergoing dynamic stress disturbance in roadway subjected to static stress

Rock bursts are sudden instability phenomena of a coal mass that occur under the superimposed action of dynamic and static stresses. Current research on the mechanism of rock bursts primarily focuses on the inherent properties of coal-rock masses. However, there have been few studies on the effects of dynamic and static stresses on the characteristics of roadway structures. Therefore, this study initially introduces the concept of the key block under rock burst conditions, simplifies external disturbances into plane stress waves, and establishes a mechanical model for the instability of the key block under combined static and dynamic stresses. The mechanical criteria for the disturbance-induced instability of the key block were derived, highlighting that the stability of the key block system is influenced by the physico-mechanical properties of the surrounding rock, as well as by the intensity and frequency of both static and dynamic stresses. Additionally, the study obtained an expression for the critical dynamic stress and analyzed the impact of various damping parameters, elastic moduli, and static stresses on the stability of the key block. Finally, a laminated rubber bolt plate component was proposed to mitigate the risk of abrupt destabilization of the key block owing to disturbances.