沉管隧道三维地震反应分析

Three-Dimensional Seismic Response Analysis of Immersed Tunnel

以京沪高速铁路南京长江沉管隧道为背景,研究地震动作用下沉管隧道的响应,计算中计及水的影响,采用粘 弹性人工边界以模拟地基的无限性.由模态计算得到体系的振型和频率,以确定积分时间步长和阻尼系数.运用Newmark隐式时间积分方法,计算了100a超越概率63%,10%和2%地震动作用下沉管隧道的反应,确定了管身段和接头部位的应力和位移.计算结果可为沉管隧道设计提供参考.

Based on the immersed tunnel which is planning to drill through the Changjiang river in Nanjing in the high speed railway from Beijing to Shanghai, the seismic response analysis of the tunnel is studied in this paper. The effect of the river is considered and a viscousspring boundary is applied in order to simulate the semiinfinity feature of the soil. The damp coefficients and the rational step time of vibration analysis are defined applying the subspace iteration method. Finally, Based on Newmark Stepbystep time integration method, the dynamic response of the tunnel is analyzed under three seismic load situations: 63% exceeding probability, 10% exceeding probability, and 2% exceeding probability in 100 years. The stress and the displacements in liner and in tiein are determined. The numerical results will provide reference for the design of the tunnel.