地铁运行振动诱发地层和地表动力响应分析

Analysis of Dynamic Response of Stratum and Ground Induced by Metro Operating

采用FLAC3D三维弹塑性动力有限差分模型,综合考虑地层和地表受振相互效应现象,对广州地铁某区间隧道运行列车振动诱发的地层和地表动力响应进行了分析。结果表明,在地铁运行振动作用下,地层的位移响应和速度响应向下和两侧衰减较快,但向上衰减较慢,对地表产生了较大范围的影响;地表振动加速度在隧道正上方强度最大,往两侧逐渐减弱,而在离开隧道轴线一定距离部位出现了一加强区。计算结果与现场实测数据吻合良好。

The elastoplastic 3D dynamic finite difference model was established by using FLAC3D numerical software. By fuUy considering the inter-effect phenomena of vibration between the stratum and the ground, dynamic response of the stratum and the ground under the vibrating load induced by metro train was numerically simulated. The results show that, under metro-train vibrating load, the dynamic response of displacement and velocity is damped quickly in both downward and lateral directions. While it is damped slowly upwards, which results in a large affected zone on the ground. The vibrating acceleration on the ground is strongest over the tunnel, and weakens gradually in the lateral directions. It is amplified at a certain distance away from tunnel central line. The simulation results were conformed favorably with the site test.