In this paper, the Excavation-induced Disturbance (ED) under high geo-stress conditions is studied through the use of a method combining theoretical calculation and field vibration analysis. The influence of every component of ED on the initiation and propagation of cracks and formation of rock burst is studied as well. The results show that the vibration monitored during blasting-excavation under high in-situ stress conditions consists of Vibration Induced by Blasting load (VIB) and Vibration Induced by in-situ stress transient Unloading (VIU). VIU becomes the main part of ED under a certain level of in-situ stress as it surpasses VIB. Both components of ED can make the cracks that extend paralleling to the free face; however, their mechanisms are different from one another. The blasting load rapidly reaches its peak value and then unloads in tens of milliseconds due to its character of impact. The tensile stress in the radial direction, induced by the unloading of the blast load, leads to initiation and extension of the circumferential cracks in the rocks around the blast holes. However, in the process of geo-stress transient unloading, radial stress unloads first and then rebounds, while tangential stress increases when the wave-front of transient unloading stress wave goes through. The combination of them makes the dynamic shearing stress increase and directly leads to the initiation and propagation of circumferential cracks. Therefore, sufficient attention should be paid to the unloading effect of geo-stress during blasting under high in-situ stress conditions.
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