基于复变理论的盾构隧道围岩位移预测分析

Elastic Complex Variable Theory Based Prediction of Shield Tunnel Surrounding Rock Displacement

  • 摘要: 为了揭示盾构隧道在不同位移边界条件下的围岩位移分布情况,将该问题简化为含圆形孔洞的弹性半无限平面第二类基本问题,运用弹性复变函数理论,结合洞周5种不同位移收敛模式,推导了两个位移复势函数φ(z)和ψ(z)的表达式,给出了围岩任意一点位移分量(u,v)的解析通式,并讨论了不同埋深与不同位移边界条件下围岩位移分布规律。基于理论公式,预测了工程实例的地表沉降,并将预测结果与实测数据进行了对比分析。研究结果表明:(1) 当隧道半径r0=4.0 m、泊松比μ=0.3,隧道埋深h从2r0增为6r0时,地表相对沉降量最大值Δvmax变化范围为0.33~1.94,地表沉降影响范围约为28.7~124.1 m,地层相对水平位移最大值Δumax随埋深变化不大,且最大值Δumax处于隧道中心水平线附近;(2)在5种不同位移收敛模式中,有两种模式预测的地表沉降值与实测数据较为吻合,其理论解可为指导隧道设计和施工提供理论基础。

     

    Abstract: To reveal the surrounding rock displacement distribution of shield tunnels under different displacement boundary conditions, it simplified it as the second basic problem of elastic semi-infinite plane with a circular hole, and the expression of two complex variable functions φ(z) and ψ(z) as well as an analytical general formula of the displacement component (u, v) at any point on a rock mass were deduced by combining the elastic complex function theory and five different displacement convergence modes around a tunnel. The displacement distribution rules of surrounding rock under different buried depths and displacement boundary conditions were discussed. Based on the theoretical formula, surface settlement of a certain project was predicted and a comparison between the predicted data and measured data was made. The results show that: when the tunnel radius r0 is 4.0 m, the Poisso ratio μ is 0.3, and the tunnel depth h is 2r0 to 6r0, then the maximum relative surface settlement Δvmax ranges from 0.33 to 1.94, and the influence area induced by surface settlement ranges from 28.7 m to 124.1 m; the buried depth has little influence on the maximum relative horizontal displacement Δumax, which is located near the central horizontal line of a tunnel; in five different modes of displacement convergences, the solution results of two displacement boundary conditions are consistent with the measured surface settlements, and therefore these two theoretical solutions can be used as a foundation of tunnel design and construction.

     

/

返回文章
返回