地铁振动预测的周期性有限元-边界元耦合模型

A coupled periodic finite element-boundary element model for prediction of vibrations induced by metro traffic

针对地铁列车运行引起的隧道结构和自由场中的振动响应问题,提出了一个在频率-波数域内的三维周期性有限元-边界元耦合的数值模型,此模型中隧道结构采用有限元法计算,自由场采用边界元法模拟。此模型采用Floquet变换,利用隧道和自由场在隧道轴线方向上的周期性,把无限长的隧道及自由场的网格划分限制在一个基本元内,这样使动力学数值计算的效率大大提高。利用此模型计算了在隧道底板上施加固定单位谐振荷载情况下隧道-自由场相互作用系统的动力响应,结果表明此模型可应用于地铁列车运行引起的隧道和自由场中的动力响应预测。

A three-dimensional coupled periodic finite element （FE）-boundary element （BE） model in the frequency-wavenumher domain is presented to predict the vibrations induced by metro traffic in the tunnel and the free field. The dynamic tunnelfree field interaction problem is solved based on the finite element method for the tunnel and the boundary element method for the free field. In this model, the periodicity of the tunnel and the soil in the direction of tunnel axis is exploited through the Floquet transform to limit the discretization effort to a single bounded generic cell, which can efficiently perform the dynamic numerical prediction. And the response of tunnel-free field interaction system due to a concentric non-moving harmonic unit excitation on the tunnel invert is studied. The results show that the model can be used to predict the vibrations induced by the passage of metro trains in the tunnel and the free field.