武当群片岩隧道围岩变形破坏机理研究

Research on the Surrounding Rock Deformation and Failure Mechanism of Wudang Group Schist Tunnel

围岩的变形破坏一直是隧道研究的热点问题,弄清围岩的变形破坏机理是解决该类问题的关键。依托在建的通省隧道,在调查隧道区工程地质条件及典型围岩变形破坏特征的基础上,分析围岩的变形破坏模式,探讨围岩的变形破坏机理。研究结果表明,围岩变形破坏归纳为对称模式、非对称模式两种。对称模式下,围岩应力、位移、塑性区呈关于水平面对称的分布形式;非对称模式下,洞周环向应力的量值会增大约15%,应力、位移、塑性区的分布将会发生偏转。围岩变形破坏机理总结为,不同的片理倾角导致了不同的洞周环向应力的量值和分布,而洞周环向应力分布又与片理呈现出一定的交切关系,形成了两种变形破坏模式。

The surrounding rock deformation and failure has been the hot issue in tunnel studies, and making clear the rock deformation mechanism is the key to solve this kind of problem. In the article the deformation and failure mode of the tunnel rock are analysised, the deformation mechanism of the surrounding rock is discussed based on the research on the engineering geological conditions and the deformation characteristics of surrounding rock of the Tongsheng Tunnel. The results show that. （1） There are two modes of the surrounding rock deformation and failure-symmetric mode and asymmetric mode. Under the symmetric mode, rock stress, displacement and plastic zone are in the level symmetric distribution form; while under the asymmetric mode, the hoop stress values of the cave will increase approximately by 15%, the distribution of the rock stress, displacement and plasnc zone will deflect. After the deflecting, the ellipse＇s long axis of the hoop stress always in the quadrant of the original symmetric mode, and is intersected with foliation of moderate angle （40°～55°） ; and （2） The surrounding rock deformation and failure mechanisms are summarized as follows, different foliation loft lead to different magnitude and distribution of the hoop stress around the holes, however the distribution of the hoop stress around the holes presents certain cross-cut relationship with the foliation loft, forming two types of deformation and failure modes.