考虑衬砌劣化的山岭隧道地震易损性分析  

Seismic fragility analysis of mountain tunnels considering lining degradation

作　　者：丁祖德[1] 资昊 计霞飞 施成华[2] 任志华 DING Zude;ZI Hao;JI Xiafei;SHI Chenghua;REN Zhihua(Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming,Yunnan 650500,China;School of Civil Engineering,Central South University,Changsha,Hunan 410075,China;Yunnan Research Institute of Highway Science and Technology,Kunming,Yunnan 650051,China)

机构地区：[1]昆明理工大学建筑工程学院,云南昆明650500 [2]中南大学土木工程学院,湖南长沙410075 [3]云南公路科学技术研究院,云南昆明650051

出　　处：《岩石力学与工程学报》2020年第3期581-592,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51768028,51308270);云南省交通厅科技项目(2017A-04)。

摘　　要：隧道服役环境往往较为复杂,在服役过程中容易遭受各种侵蚀作用而导致材料性能退化,直接影响隧道结构的抗震性能。为研究衬砌劣化对隧道抗震性能的影响,基于混凝土强度经时模型和钢筋锈蚀参数的统计特征,确定混凝土及钢筋材料性能的退化规律,建立衬砌时变承载力方程。结合地震易损性分析方法,提出考虑衬砌劣化的山岭隧道地震易损性评估流程。以西部强震区典型深埋山岭隧道为例,采用增量动力分析方法开展一系列二维动力时程计算,基于Python语言编程,实现地震响应结果数据的自动提取和基于地震响应全过程结构最大损伤指数(DImax)的搜索计算。在此基础上,建立考虑混凝土劣化、钢筋腐蚀以及两者共同作用条件下,不同服役年限隧道的地震易损性曲线。结果表明:衬砌的易损性随服役时间的增加呈两阶段非线性增大,服役前期(0~50 a)增加缓慢,服役后期(50~100 a)增速加快。说明服役时间越长,衬砌劣化对隧道地震易损性的影响越大。在评价既有隧道抗震性能时,需考虑长期材料性能劣化的影响。此外,不同围岩级别下隧道易损性曲线随服役时间的变化规律相似,围岩级别和衬砌劣化一样,均对隧道地震易损性有重要影响,具体表现为衬砌的损伤概率随围岩变差而增大。所得结论可为运营隧道易损性分析和风险评估提供参考。Mountain tunnels are typically located in complex geological environments,and the seismic performances of the tunnels are directly affected by the degradation of tunnel linings resulted from various erosions during the service life.The degradation laws of concrete and steel bars were determined by introducing the time-dependent concrete strength model and statistical characteristics of corrosion parameters of steel bars,and a time-dependent load carrying capacity formula of tunnel lining was established applying the load-bearing capacity equation of eccentric compression members and the time variable.According to the theory of seismic fragility analysis,an assessment process of seismic vulnerability of mountain tunnels considering lining degradation was proposed.A deep buried mountain tunnel in western China was taken as an example,a series of 2D dynamic time history calculations were carried out by using the incremental dynamic analysis method.An automatic extraction of the data and an automatic calculation of the maximum of damage index(DImax)during the seismic response process were implemented by using the Python programming language.Seismic vulnerability curves of tunnels with different service life were obtained considering the deterioration of concrete and the corrosion of steel bars.The results show that the vulnerability of the lining increases nonlinearly with increasing the service time.The damage probability of the lining increases slowly in the early stage of the service(0-50 years),while increases rapidly in the late stage of the service(50-100 years),showing that the longer the service time,the greater the effect of lining corrosion on seismic vulnerability of tunnels.Therefore,it is necessary to take into account the deterioration of linings for the risk assessment of operational tunnels.In addition,the shapes of the fragility curves of tunnels within the service time are similar for different surrounding rocks.The important effects of surrounding rocks and lining degradation on the vulnerability o

关 键 词：隧道工程 耐久性损伤 钢筋腐蚀 混凝土劣化 易损性曲线 

分 类 号：U45[建筑科学—桥梁与隧道工程]