沉管隧道纵向抗震韧性评价方法研究

Seismic Resilience Assessment for Longitudinal Response of Immersed Tunnels

抗震韧性是评估结构抗震性能的重要手段,但目前对沉管隧道纵向抗震韧性评价的研究较缺乏。基于梁-弹簧模型建立能够合理考虑沉管隧道结构特征及接头构造的沉管隧道多尺度分析模型,选择合理的评估指标,根据不同极限状态定义获得地震易损性曲线,通过构建合理的性能恢复函数计算隧道韧性指数,从而建立沉管隧道抗震韧性评估方法,并以某沉管隧道实际工程为例进行隧道抗震韧性分析,揭示地震动强度及地层-结构相对刚度比等关键参数的影响规律。研究结果表明,随着PGA的增加,隧道震后剩余功能函数显著下降,隧道抗震韧性明显降低;隧道韧性指数随着地层-结构相对刚度比的增大而增大。

Seismic resilience assessment is an important means to evaluate the seismic performance of structures,but the seismic resilience assessment for longitudinal response of immersed tunnels has not been reported yet.Based on the beam-spring model,a multi-scale analysis model of immersed tunnel was established,which took the characteristics and joints of immersed tunnels into consideration.Fragility curves were developed at different limit states with reasonable intensity measure and damage measure.The seismic resilience assessment framework were modeled by the estimation of restoration functions and the resilience index.Taking an immersed tunnel as an application example,parametric analyses were performed to investigate the influence of the peak ground acceleration and soil-structure relative stiffness ratio.The results show that the residual functionality and seismic resilience decrease significantly with the increase of the PGA.The seismic resilience index increase with increasing soil-structure relative stiffness ratio.