既有浅埋公路隧道原位扩容围岩变形

Deformation of Surrounding Rock with in-situ Expansion of Shallow Highway Tunnel

针对既有浅埋公路隧道原位扩容方式对围岩变形影响程度问题,采用FLAC3D数值模拟软件,对既有浅埋公路隧道单侧扩容方式和均匀扩容方式对隧道围岩变形的影响进行数值模拟分析研究.研究结果表明:既有公路隧道均匀扩容方式下的顶底板收敛量大于单侧扩容方式下的顶底板收敛量,而均匀扩容方式下的两帮收敛量小于单侧扩容方式下的两帮收敛量;既有公路隧道原位扩容可导致围岩产生一定量的变形,但变形量未对隧道安全性造成明显影响.在围岩属于稳定级别时,扩容方式对围岩变形影响不明显,在施工时只需进行常规支护.

Aimed at the influence degree of the in-situ expansion of the existing shallow highway tunnel on the surrounding rock deformation, the numerical simulation software FLAC^3D is applied to simulate and analyze the influence of the uniform expansion way and the unilateral expansion way of the existing shallow highway tunnel on the surrounding rock deformation. Research resuhs show that the convergence rate of the top and bottom roof under the uniform expansion way is larger than that of the single side expansion way, while the convergence rate of the two sides under the uniform expansion way is less than that under the unilateral expansion way. The in-situ expansion of highway can lead to produce a certain amount of deformation, but it does not affect the safety of tunnel. When it is at the stable level, the expansion mode of surrounding rock deformation is not obvious. In construction, it is only necessary to carry out conventional support.