地震作用对盾构隧道管片张开量的影响及预测

Impact on and Prediction of Segment Opening of Shield Tunnels under Seismic Action

为探索地震作用对盾构隧道管片张开量的影响,借助数值分析软件,分析典型工程在不同方向地震作用下管片张开量的分布规律。基于计算结果,对地震加速度与地震引起的管片张开量进行归一化处理,结合现有的管片张开量计算公式,提出了不同埋深隧道在地震作用下管片最大张开量预测方法。研究表明:地震作用对盾构管片环缝张开量有显著的影响,管片最大张开量的最大增幅为16%,平均张开量的最大增幅为27%;地震烈度为8度以下的区域,在静、动荷载作用下,盾构隧道管片抗震加固范围主要在工作井附近3~5环;地震烈度为8度及以上的高地震烈度区,应沿隧道轴向对环缝接头进行抗震加固。与数值计算结果对比表明,提出的考虑地震作用的管片最大张开量计算方法具备一定合理性。

In order to explore the effect of seismic action on the segment opening of shield tunnels, by using numerical analysis software, this paper analyzes the distribution law of segment opening under seismic action with different directions in a typical project. On the basis of the calculation results, this paper normalizes the segment opening indued by seismic acceleration and the seismic action with combined consideration to the existing calculation equations of segment opening, and puts forward the prediction method of the maximum segment opening under seismic action in tunnels with different depths. The study shows that seismic action has a significant impact on the opening of circumferential segment joints, with the maximum opening of the segments increasing by 16% and the average opening increasing by 27% at least;in areas with a seismic intensity of less 8 degrees, the anti-seismic reinforcement scope of the shield tunnel segments is mainly at 3-5 rings in the vicinity of the working shaft under static and dynamic loads;in high seismic intensity areas with a seismic intensity of 8 degrees and above, the anti-seismic reinforcement of the circumferential joints along the tunnel axis should be carried out. The comparison with the numerical calculation results shows that the proposed calculation method of the maximum segment opening under seismic action is reasonable to a certain extent.