基于黏弹性边界的地下隧道非线性地震响应分析模型

A Nonlinear Seismic Response Analysis Model for UndergroundTunnels Based on the Viscous spring Boundary

摘要:

采用黏弹性边界方法和地震动输入等效节点力方法模拟半无限场地的地震激励，结合通用有限元软件ANSYS，建立地下隧道地震响应分析模型。模型采用等效线性化方法模拟土体非线性，采用瑞利阻尼和材料阻尼相结合方法模拟土体阻尼，分别考虑衬砌中混凝土和钢筋的非线性，以及衬砌和土体之间的接触。通过与文献比较，对整体模型的精度进行验证，并以天津市深厚覆盖层场地中某地铁双隧道为例进行非线性地震响应分析。研究表明，隧道间距较小时隧道之间存在显著相互作用，非线性地震动应力显著增大。本文模型可用于地下隧道一类结构的抗震验算分析。

Abstract:

This paper presents a model for the nonlinear seismic response analysis of tunnels，in which the viscous-spring boundary method and the earthquake equivalent node force input method are combined for half-space seismic excitation and the general finite element software ANSYS is utilized for analysis.The model uses the equivalent linear method to model soil nonlinearity and combines Rayleigh damping and material damping to model soil damping.Concrete and reinforcement nonlinearity are considered separately，and soil-liner contact is taken into account. The model is validated through comparisons with the results in the existing literature.The nonlinear seismic response of the metro twin tunnels in Tianjin City with thick soil layers is implemented，and it is shown that when two tunnels are close, the tunnel tunnel interaction is significant and nonlinear seismic stresses of the two tunnels become larger.This model can be used for the nonlinear seismic analysis of underground structures.