港珠澳大桥海底沉管隧道弹塑性地震响应分析

Seismic elasto-plastic response analysis of subsea immersed tunnel of Hong Kong-Zhuhai-Macao Bridge

为研究海底沉管隧道在横向地震作用下的动力响应特征,以港珠澳大桥沉管隧道为研究背景,基于ABAQUS软件平台建立了海水-海床-管片相互作用的三维有限元模型,考虑了海床土体非线性动力特性和隧道混凝土塑性损伤。采用动力时程分析方法研究隧道在不同地震峰值加速度激励下的地震响应特征。结果表明:沉管隧道最先出现损伤的区域为中墙与顶板连接处,但折拱段的震后损伤最为严重,是沉管隧道的最薄弱部位;在输入地震峰值加速度大于0.4g的情况下,隧道管片折拱段与侧墙等区域会面临震后渗水的次生灾害风险。研究成果可为水下沉管隧道的抗震性能设计提供参考。

In order to study the dynamic response characteristics of the immersed tunnel under the horizontal ground motion,a 3-D finite element model,considering the seawater-seabed-segment interaction,was established using the ABAQUS software platform,with the Hong Kong-Zhuhai-Macao Bridge Immersed Tube Tunnel as the research context.The model also incorporated the nonlinear dynamic characteristics of seabed soil and the plastic damage behavior of the tunnel concrete.The seismic response of the tunnel segments to varying levels of ground motions was analyzed using the dynamic time history analysis.The results indicate that the initial damage occurs at the connection between the middle wall and the roof of the tunnel,but the folded arch section experiences the most severe post-earthquake damage,making it the weakest part of the tunnel.When the peak ground acceleration of input ground motion exceeds 0.4g,regions such as the folded arches and the side walls will become susceptible to post-earthquake water seepage secondary hazards.The above research results can serve as a valuable reference for the seismic performance design of immersed tunnels.