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结合锦屏二级水电站深埋隧洞典型岩爆案例,分析板裂屈曲岩爆的发生机制及结构面作用机制,研究表明:开挖卸荷作用导致围岩板裂化结构的形成,切向集中应力作用下岩板向开挖空间内屈曲变形并积聚应变能,当板裂化围岩结构自身积聚的能量超过其储能极限,或在外界扰动作用下发生突发性失稳破坏,形成以岩板压折、岩块弹射为特征的岩爆现象;渐进的板裂化破坏过程起到了活跃结构面的作用,而结构面的存在及其扩展降低了板裂化围岩结构的稳定性,促进了岩爆的发生;不同倾角的结构面在板裂屈曲岩爆中的作用机制不同。结合板裂化围岩的结构特征,配制板裂化模型试样,采用2种不同的加载方式进行板裂屈曲岩爆的物理模拟试验,结果表明:预制裂隙的扩展将试样劈裂成板,压缩荷载进一步作用下岩板向临空面屈曲变形,并最终形成岩板压折、岩片弹射的失稳破坏现象。研究结果对于认识深埋隧洞板裂屈曲岩爆机制及其支护控制具有重要意义。
Combining with the typical rockburst of the deep tunnel in Jinping Ⅱ Hydropower Station, the mechanism of the rockburst and the action mechanism of the structural plane are analyzed. The results show that the formation of the cracked structure of the surrounding rockmass and the stress concentration in the tangential direction Under the action, the rock plate buckles and deforms in the excavation space and accumulates strain energy. When the energy of the plate crack surrounding rock structure accumulates exceeds its energy storage limit or emerges instability damage under the external disturbance, Pressure fracture and rock ejection. The progress of progressive plate cracking and destruction plays an active role in the structural plane, while the existence and expansion of the structural plane reduce the stability of rock mass surrounding the plate and promote the rock burst . The action mechanism of the structural planes with different dip angles in the buckling rock burst is different. Combined with the structural characteristics of cracked surrounding rock, the slab cracking model specimens were prepared and the physical simulation tests of buckling rockburst with two different loading methods were carried out. The results show that: the pre-existing crack propagation splits the specimen into plate, Under further load, the rock slab buckling deformation to the surface, and eventually the formation of rock fold, rock ejection instability damage phenomenon. The research results are of great significance for understanding the mechanism of rockburst and its support control in deep tunnel.