考虑轴力作用下盾构下穿引起既有隧道变形解析解  

Analytical Solution for Deformation of Existing Tunnel Induced by Underlying Tunneling Considering Axis Force Influence

作　　者：乔晓延 齐晓强 QIAO Xiaoyan;QI Xiaoqiang(CCCC Second Highway Engineering Co.,Ltd.,Xi'an 710065,China;School of Civil Engineering,Qingdao University of Technology,Qingdao 266033,China)

机构地区：[1]中交第二公路工程局有限公司,西安710065 [2]青岛理工大学土木工程学院,青岛266033

出　　处：《铁道标准设计》2022年第12期98-103,共6页Railway Standard Design

基　　金：国家重点研发计划项目(2017YFC0805300)。

摘　　要：为研究盾构下穿对上覆既有隧道变形的影响,首先,采用修正Loganathan公式求解盾构开挖引起既有隧道轴线处的土体自由位移;其次,把土体自由位移转化成附加应力施加在既有隧道上,将既有隧道简化成无限长EulerBernoulli梁搁置在Kerr地基模型上,引入隧道轴力的二阶效应,根据既有隧道两端自由的约束条件提出盾构下穿引起既有隧道受力变形解析解。研究结果表明:与既有文献实测数据验证对比,本文所提方法计算结果与实测较为符合;与本文方法退化解析比较,本文方法预测结果更具有优越性。参数分析得到如下结论:地层损失率增大,既有隧道位移及其内力呈线性增大趋势;随着隧道开挖轴线埋深增加,既有隧道位移和内力均会大幅度减小;随着下穿隧道开挖直径增大,上覆既有隧道变形及其内力显著增大。In order to figure out the influence of existing tunnel induced by underlying tunneling,firstly,the soil-free settlement of tunnel centerline caused by underlying tunneling is calculated by Loganathan function.Secondly,the additional loading on the existing tunnel is transferred by soil-free settlement.The existing tunnel is simplified as Euler-Bernoulli beam lying on Kerr foundation model and the tunnel axis force second-order effect is taken into consideration.Then,a deformation analytical solution of the existing tunnel is proposed based on the condition of the freedom of the two tunnel ends.Studies show that,compared with the measurements,the proposed method solutions have more in accord with the measurements.By comparing with degraded solution based on the proposed method,the prediction of proposed method is more superior.Further studies show that both the deformation and bending moment of the tunnel linear increase with the volume loss;with the depth of existing tunnel centerline increasing,tunnel deformation and inner force will be increased;with the diameter of shield tunneling increasing,the deformation and inner force of the existing tunnel increase significantly.

关 键 词：盾构隧道 下穿既有隧道 EULER-BERNOULLI梁 地基模型 轴力作用 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]