隧道围岩结构面倾角对诱发岩爆的影响研究

Influence of Structural Plane Inclination Angle on Induced Rock Burst in Deep Tunnels

为了解结构面倾角对诱发岩爆动力失稳行为的影响,通过采用GDEM数值模拟软件,开展了含不同角度闭合多节理的直墙拱形隧道在全断面开挖卸荷作用后对诱发结构面型岩爆的数值模拟研究,分析了隧道在开挖卸荷下围岩的裂纹扩展行为、应力变化、碎块体的体积与块体的弹射速度等力学特征。研究表明,由于围岩内节理倾角空间位置的不同,导致在隧道开挖卸荷后,容易在节理尖端围岩处形成应力集中,造成不同程度的应力重分布,改变了围岩裂纹的扩展行为和承载能力。且围岩破坏模式受结构面倾角的影响明显,缓倾角强化了结构面的抗剪切作用,不易形成岩爆。陡倾角易诱发压剪滑移破坏,诱发岩爆。研究结果对含节理隧道的开挖设计与灾害防治有重要的工程意义和学术价值。

In order to understand the influence of structural plane dip Angle on the dynamic instability behavior of induced rock burst,a straight wall arch tunnel with multiple joints closed at different angles was carried out by using GDEM numerical simulation software.After full section excavation and unloading,the induced rock burst of structural plane was numerically simulated.The mechanical characteristics of surrounding rock such as crack propagation behavior,stress variation,volume and ejection velocity of the block under tunnel excavation and unloading are analyzed.The results show that the different degrees of stress concentration can be easily produced at the tip of the joint after the tunnel excavation,due to the difference in the spatial position of the structural plane.As a result,the difficulty of the crack generation in the surrounding rocks is varying,which changes the crack propagation behavior and bearing capacity of the surrounding rocks.The failure modes of the surrounding rock are obviously affected by the structural plane inclination angle.The gentle inclination angle strengthens the anti-shear behavior of the structural plane,resulting in no or slight rock burst.A steep inclination angle can easily induce rock burst due to the compression-shear slip failure of structural planes.The research results have great engineering and academic values for the excavation design and disaster prevention of the jointed tunnel.