非一致激励下长距离沉管隧道纵向地震响应分析

The non-uniform seismic excitation, the dynamic properties of immersion joints and the dynamic soil-structure interaction are key factors affecting the longitudinal seismic response of immersed tunnels. However, these factors are insufficiently considered in current simplified analysis methods due to their simplified models. Furthermore, three-dimensional dynamic analysis is not suitable for long immersed tunnels due to the complexity of modeling and computation. In this proposal, an analysis method and its accompanying model for the longitudinal seismic response of long immersed tunnels subjected to non-uniform seismic excitations are studied in detail. Both the theoretical and numerical techniques are used to facilitate the research. In this proposal, a multimodal equivalent model for foundation soils considering the nonlinearity is first developed based on mode equivalence theory and equivalent linearization method. The dynamic soil-structure interaction impedances for the immersed tunnel-foundation system are then derived by using Green’s influence function method and indirect boundary element method. Based on the structural characteristics and the nonlinear dynamic properties of the immersion joint, a three-dimensional dynamic model of immersed tunnel-foundation system is proposed. Through formulating the equation of motion for the immersed tunnel-foundation system subjected to multi-support excitations and solving it numerically, the longitudinal seismic response analysis of long immersed tunnels is finally realized.

非一致地震激励、管节接头动力性能以及土-结构动力相互作用是影响沉管隧道纵向地震响应的关键因素。但当前的简化分析方法都因模型简化而无法充分考虑这些因素，而三维整体动力分析也因其复杂的建模计算对长距离沉管隧道适用性较差。本项目以沉管隧道-地基系统为研究对象，采用理论分析与数值计算相结合的研究手段，系统研究有效求解非一致激励下长距离沉管隧道纵向地震响应的分析模型和计算方法。基于模态等效理论和等效线性方法，构建考虑地基土材料非线性的多模态等效模型；采用格林影响函数法和间接边界元法，求解沉管隧道-地基系统的土-结构动力相互作用参数；针对管节接头构造特点及其非线性动力特性，建立沉管隧道-地基系统的三维动力分析模型；推导多点非一致基岩激励下沉管隧道-地基系统的运动方程并进行数值求解，实现非一致激励下长距离沉管隧道纵向地震响应分析。

本项目以沉管隧道-地基系统为研究对象，采用理论分析与数值计算相结合的研究手段，系统研究有效求解非一致激励下长距离沉管隧道纵向地震响应的分析模型和计算方法。基于模态等效理论和等效线性方法，构建考虑地基土材料非线性的多模态等效模型；采用格林影响函数法和间接边界元法，求解沉管隧道-地基系统的土-结构动力相互作用参数；针对管节接头构造特点及其非线性动力特性，建立沉管隧道-地基系统的三维动力分析模型；推导多点非一致基岩激励下沉管隧道-地基系统的运动方程并进行数值求解，实现非一致激励下长距离沉管隧道纵向地震响应分析。