盾构隧道拱顶渗流侵蚀对地表沉降及结构变形的影响

Effect of seepage erosion of tunnel crown on ground settlement and structural deformation in shield tunnelling

通过建立三维隧道数值模型研究渗流侵蚀对地表沉降及结构变形的影响。基于渗流侵蚀试验,应用强度及刚度折减法定性模拟渗流侵蚀过程;建立盾构隧道施工模型,通过对比数值模型与现场实测数据验证数值模型的可靠性;研究渗流侵蚀对地表沉降及结构变形的影响。结果表明:拱顶部位渗流侵蚀引发的地表沉降量呈指数增长趋势;侵蚀过程的卸载作用使管片明显上抬,管片错台量逐渐增大;渗流侵蚀扩散范围越大,地表沉降及管片结构变形越大。

By establishing the three-dimensional numerical model of tunnel,this study investigated the effect of seepage erosion on ground settlement and structural deformation.Firstly,the strength and stiffness reduction approaches were adopted to qualitatively simulate the erosion process based on the triaxial erosion tests.Then a comparison of ground settlements between the field monitoring and the numerical result was conducted to verify the reliability of the numerical approach.The effects of seepage erosion on ground settlement and structural deformation were investigated in the end.The results indicated that the ground settlement induced by the progressive erosion process increased exponentially.The linings were pushed upward due to the erosion-induced unloading as seepage erosion occurred on the tunnel crown,and then resulted in a gradual increase of dislocation of segment joints.The extension of erosion region increased the ground settlement and structural deformation according to the parametric study.