穿越断层破碎带隧道超前注浆加固效果分析

Analysis on reinforcement effect of advanced grouting for tunnel crossing fault fracture zone

为研究断层破碎带超前注浆加固机理,以阳宗隧道穿越多条断层破碎带实际工程为依托,运用FLAC3D软件建立穿越断层破碎带三维数值模型,研究不同厚度、不同注浆范围的超前小导管注浆加固对断层破碎带围岩的控制效果。研究结果表明:1)注浆加固层厚度的增大对隧道竖向位移,尤其是对隧道拱顶沉降的控制效果明显,对隧道围岩水平位移的控制亦有效果,但效果稍差。当采用1.5 m注浆加固层厚度时,隧道拱顶最大沉降和围岩最大水平位移分别降低了26.96%、16.03%。2)随着超前小导管注浆范围的扩大,隧道围岩水平位移的控制效果明显变得更好,竖向位移的控制效果变化不大。当采用150°的注浆范围时,隧道拱顶最大沉降和围岩最大水平位移分别降低了26.62%、22.80%。3)采用超前小导管注浆加固,增强了断层破碎带围岩的强度,控制了软弱围岩的变形量,使围岩整体稳定性得到有效提高。该研究成果为隧道现场施工提供了依据,对类似隧道施工具有一定的借鉴意义。

To study the mechanism of advanced grouting reinforcement in fault fracture zone,based on the actual project of the Yangzong tunnel crossing multiple fault fracture zones,a three-dimensional numerical model of crossing fault fracture zone is established using FLAC3D software.The control effect of advanced small pipe grouting reinforcement with different thicknesses and grouting ranges on the surrounding rock of fault fracture zones is studied.The results show that:1)The increase in the thickness of the grouting reinforcement layer has a significant control effect on the horizontal displacement of the tunnel,especially on the settlement of the tunnel arch.It also has a control effect on the horizontal displacement of the tunnel,but it is not as effective as the control effect on the settlement of the arch.When the thickness of grouting reinforcement layer is 1.5 m,the tunnel crown settlement and maximum horizontal displacement are reduced by 26.96%and 16.03%,respectively.2)With the expansion of grouting range of the advanced small pipe grouting,the control effect on the horizontal displacement of the tunnel significantly becomes better,while the control effect on the vertical displacement has little change.When the grouting range is 150°is used,the tunnel crown settlement and convergence of the periphery are decreased by 26.62%and 22.80%,respectively.3)The strength of the surrounding rock in the fracture zone of fault is enhanced,the deformation of the weak surrounding rock is controlled,and the overall stability of the surrounding rock is improved effectively through the reinforcement of the advanced small pipe grouting.The research findings provide a basis for tunnel construction on-site and are of certain reference significance for similar tunnel construction projects.