地震动非一致性对隧道动力响应的影响分析

Seismic Response Analysis of Tunnel under Multi-point Seismic Motion

摘要:

针对隧道的抗震安全性，借助有限元软件平台对其地震时程响应进行非线性有限元分析。利用弹性模型考虑混凝土隧道在循环荷载作用下的拉、压应力-应变关系，同时对土体采用Mohr-Coulomb模型，选用人工边界作为边界条件，以人工合成的多点地震加速度时程作为地震动输入，分别考虑一致输入、行波效应、相干效应及行波加相干效应对隧道的影响。分析结果表明，与一致激励的计算结果相比，非一致地震激励会显著增加隧道结构的内力和位移响应，从而对隧道抗震产生不利影响。研究结论可为长隧道结构的抗震设计和分析提供科学依据。

Abstract:

To guarantee the safety of a tunnel, a nonlinear numerical analysis of an earthquake is carried out by using the FEM software. The elastic model was used to model the characteristics of concrete tunnel under circulating load. The Mohr-Coulomb model was adopted for soils, and the artificial boundary was chosen as the boundary condition. For the purpose of comparing the responses of uniform waves, traveling waves, coherent waves, and traveling-coherent waves, artificial multi-point earthquake acceleration was encoded into the FEM model. Compared with the calculation results of consistent excitation, the analysis shows that non-uniform seismic excitation can significantly increase both the force and displacement of the tunnel, which can have adverse effects on the seismic performance of the tunnel. This research conclusion can provide scientific basis for anti-seismic design and further analysis of long-tunnel structures.