断层破碎带形态对隧道围岩变形影响研究

Study on the Influence of Fault Fracture Zone Morphology on Tunnel Surrounding Rock Deformation

断层破碎带具有围岩破碎、强度低等特点,极易引起隧道围岩发生大变形,进而诱发工程灾害。因此,依托重庆市郊铁路璧铜线云雾山隧道工程,采用PLAXIS3D数值分析软件,建立了隧道穿越不同形态断层破碎带计算模型。计算结果表明:断层破碎带倾角和厚度对隧道围岩变形影响显著,断层走向线与隧道轴线夹角对隧道围岩变形影响较小。随着断层破碎带倾角的增大,受断层破碎带影响的范围明显缩小,隧道围岩竖向和水平位移值均逐渐减小,且当断层破碎带倾角为90°时,受断层破碎带影响的范围最小;随着断层破碎带厚度的增大,受断层破碎带影响的范围随之增大,围岩的竖向和水平位移值均逐渐增大,且当断层破碎带厚度为22 m时达到最大值。隧道正交穿越断层破碎带薄弱处时,围岩变形控制效果会更好。该研究成果可为山岭隧道穿越断层破碎带设计与施工提供一定的参考。

Because of the characteristics of surrounding rock crushing,low intensity,fault fracture zone is easy to cause large deformation of tunnel surrounding rock,thus induce engineering disasters.Therefore,based on the Yun-wushan Tunnel project of Bitong Line of Chongqing suburban railway,PLAXISD numerical analysis software was used to establish the calculation model of tunnel through different fault fracture zones.The calculation results show that the dip angle and thickness of fault fracture zone have significant influence on the deformation of tunnel sur-rounding rock,while the angle between fault strike line and tunnel axis has little influence.With the increase of the dip angle of the fault fracture zone,the range affected by the fault fracture zone obviously reduce,and the vertical and horizontal displacement values of the tunnel surrounding rock gradually reduce.When the dip angle of the fault fracture zone is 90°,the range affected by the fault fracture zone is the smallest;With the increase of the thickness of the fault fracture zone,the range affected by the fault fracture zone increases,and the vertical and horizontal dis-placement values gradually increase and reach the maximum value when the thickness of the fault fracture zone is 22 m.The deformation control effect of surrounding rock will be better when the tunnel crosses the weak part of the fault fracture zone.The research results can provide some reference for the design and construction of mountain tunnel through fault fracture zone.