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Mechanical Mechanism of the Shear Rock Burst in Intact Surrounding Rocks
(1 School of Civil Engineering and Archiecture, Wuhan University of Technology, Wuhan 430070; 2 School of Resources and Safety Engineering, Wuhan Institute of Technology, Wuhan 430073)
Abstract According to numerous rock burst cases in engineering practice, the characteristics of shear rock bursts are summarized in this paper. On the basis of this a simplified mechanical model of shear rock burst is proposed. In consideration of the release of the energy stored in rock masses in rock burst area, the Cook Stiffness theory is used to investigate the shear rock bursts′ physical and mechanical processes. The failure of surrounding rock caused by the post-peak strain-softening of the constitutive curve of a potential shear plane, and the release of energy stored in rock masses during the failure processes are analyzed. Moreover, the unstable mechanism of shear rock burst is discussed. The results show that the shear rock burst results from the shear dislocation and slip along the potential shear plane, owing to the stress concentration after excavation. Furthermore, the shear rock burst causes the sudden and rapid energy release in the rock burst area and surrounding intact surrounding rocks, and results in the ejection of fractured rock masses toward the direction of the excavation face. In rock burst area and intact surrounding rock masses, the energy released at the shear plane serves as a pair of series springs. It is concluded that the shear rock burst is governed by the lithology, potential shear failure angle and the rock masses′ stiffness around the shear plane. Furthermore, it is a failure catastrophe that resulted from energy release and the progressive deterioration of the mechanical properties of surrounding rocks during the deformation processes.
Abstract：
According to numerous rock burst cases in engineering practice, the characteristics of shear rock bursts are summarized in this paper. On the basis of this a simplified mechanical model of shear rock burst is proposed. In consideration of the release of the energy stored in rock masses in rock burst area, the Cook Stiffness theory is used to investigate the shear rock bursts′ physical and mechanical processes. The failure of surrounding rock caused by the post-peak strain-softening of the constitutive curve of a potential shear plane, and the release of energy stored in rock masses during the failure processes are analyzed. Moreover, the unstable mechanism of shear rock burst is discussed. The results show that the shear rock burst results from the shear dislocation and slip along the potential shear plane, owing to the stress concentration after excavation. Furthermore, the shear rock burst causes the sudden and rapid energy release in the rock burst area and surrounding intact surrounding rocks, and results in the ejection of fractured rock masses toward the direction of the excavation face. In rock burst area and intact surrounding rock masses, the energy released at the shear plane serves as a pair of series springs. It is concluded that the shear rock burst is governed by the lithology, potential shear failure angle and the rock masses′ stiffness around the shear plane. Furthermore, it is a failure catastrophe that resulted from energy release and the progressive deterioration of the mechanical properties of surrounding rocks during the deformation processes.
HUO Mengzhe1 LIU Xiqi1 LIN Manqing2
.Mechanical Mechanism of the Shear Rock Burst in Intact Surrounding Rocks[J] MODERN TUNNELLING TECHNOLOGY, 2021,V58(1): 10-18
2021, Vol. 58 