盾构穿越引起的既有盾构隧道纵向变形研究

Research on Longitudinal Deformation of Existing Shield Tunnel Caused by Shield Tunneling

研究既有隧道在新建隧道穿越时产生的响应,提出一种能准确预测既有隧道位移的计算方法。采用目前国内较为先进的转动错台模型,在考虑施工因素的附加荷载作用下,运用最小势能原理对既有盾构隧道在新建隧道穿越时的结构变形进行了分析预测。并分别选取了3个工程实例对新建隧道在不同穿越工况下本文方法的预测准确性进行了验证。研究结果表明:本文方法计算值与实测值较为吻合,能计算出既有隧道的竖向位移、环间的错台量、转角和剪切力,进而判断既有隧道结构的安全状态;既有隧道发生沉降时管片以错台变形为主,转动变形占比较小(约30%)。

The response of existing tunnels when new tunnels pass through is studied,and a calculation method that can accurately predict the displacement of existing tunnels is proposed.The current advanced rotation and dislocation model is adopted.Under the condition of the additional load of construction factors,the principle of minimum potential energy was used to analyze and predict the structural deformation of the existing shield tunnel when the new tunnel passed.Three engineering examples were selected to verify the accuracy of the proposed method in different tunnels under different traversing conditions.The results show that the calculated values of the proposed method are in good agreement with the measured values,and the vertical displacement of the existing tunnel,the dislocation between the rings,the rotation and the shear force can be calculated,and the safety state of the existing tunnel structure can be judged.During the settlement of the existing tunnel,the segment is mainly deformed by the dislocation,and the rotation deformation accounts for a relatively small proportion(about 30%).