基于能量法的隧道穿越引起既有管线变形研究

Research on Deformation of Existing Pipeline Induced by Shield Tunneling Based on Energy Method

针对隧道穿越引起既有管线变形的问题,本文出发点并非沿用力学平衡,而是从系统能量入手。将既有管线视为Euler-Bernoulli梁,并搁置于可考虑地基连续变形的Pasternak地基上。参考Rayleigh-Ritz法给出位移函数,写出地基梁系统各部分的功能表达式,建立关于管线变形的总势能方程。依据最小势能原理对其进行变分运算并求解,推导得到计算管线变形的理论解析。分别利用有限元软件的模拟结果和已发表文献中实际工程的监测数据验证所提方法的合理性。进一步对既有管线抗弯刚度、新旧结构穿越角度以及地层损失率展开参数分析。研究结果表明,随着既有管线抗弯刚度和新旧结构穿越角度的增大,既有管线的变形减小;而随着地层损失率的增大,既有管线的变形也随之增大。所提方法可快速评估隧道开挖对既有管线的影响。

The start point of this paper is to figure out the deformation mechanism of existing pipelines induced by shield tunneling using the system energy technique instead of the general namely mechani-cal balance method.The existing pipeline is simplified as an Euler-Bernoulli beam on the Pasternak foundation which can deform continuously.After giving the displacement function referring to the Ray-leigh-Ritz method,the energy expressions of each component in the elastic foundation beam system are achieved,and then the total potential energy equation about pipeline deformation is obtained.Based on the principle of minimum potential energy,the theoretical method is derived to assess the pipeline deformation by employing a variational method to solve the governing equation.The rationali-ty of the proposed method is verified by comparing the calculated results with those of the simulation re-sults of the finite element software(FEM)and the monitoring data from the engineering project in the published literature.Then,the parameter analysis on the bending stiffness,cross angles and ground loss is conducted to figure out their influence on the deformation of the pipeline.The results show that with the increase of the bending stiffness of the existing pipeline and the crossing angle between the new and existing structures,the deformation of the pipeline decreases.However,the deformation in-creases as the ground loss increases.The proposed method can quickly evaluate the impact of tunnel ex-cavation on existing pipelines.