通过活断层区地铁隧道损伤分析

Damage Analysis of Metro Tunnel Across Active Fault

为了深入研究通过活断层区地铁隧道的损伤破坏机理,发现其抗震薄弱部位,采用理论分析、数值模拟和统计回归等方法对逆断层位错作用下隧道衬砌结构的损伤发展变化情况进行了分析,并对减轻隧道震害的影响因素进行了研究。结果表明:建立的地基土-隧道体系整体有限元模型能够很好地模拟逆断层的错动效果;在逆断层位错作用下,衬砌结构的拱顶部位损伤最为严重,结构的损伤程度随着位错量的增加而增大,损伤区域主要集中在活断层附近;在相同逆断层位错作用下,随着覆盖土层厚度的增加,衬砌结构的破坏程度有所减轻;给出的适用于北京地区的衬砌结构抗震薄弱部位估计公式为通过活断层区地铁隧道的抗震设计提供了参考依据;适当增加衬砌厚度可以减轻隧道结构的震害,埋置于较软土质中的隧道结构能够更好地抵抗逆断层位错作用。

In order to deeply study damage mechanism of metro tunnel across active fault,and find the seismic weak parts,the theoretical analysis,numerical simulation and statistical regression were used to analyze damage development of tunnel lining structure under reverse fault,and to research the influence factors of weakening tunnel earthquake disasters.The results show that the integrated finite element model of foundation soil-tunnel system can well simulate reverse fault movement.The destruction is the most serious at the lining vault under reverse fault,the damage degree of structure increases with increasing of dislocation,and the damage range is mainly located in active fault.The destruction degree of lining structure can reduce with the increase of soil layer thickness under the same reverse fault dislocation.The estimation formulas of lining structural seismic weak position given can provide references for seismic design of metro tunnel across active fault.Earthquake disasters of tunnel structure can be weakened by proper increase of lining thickness,and tunnel structure in soft soil has better resistance to reverse dislocation.