基于流固耦合作用的偏压连拱隧道稳定性分析

Analysis on the stability of fluid-solid coupling in a bias double-arch tunnel

针对地质条件差且多雨地段的连拱隧道,施工中的不对称性及自然地形产生的偏压效应是对工程安全影响较大的问题。以湖南省的雷家台偏压连拱隧道为工程背景,基于渗流-应力耦合分析理论,应用Midas/GTS有限元软件,模拟偏压连拱隧道开挖过程。结合工程施工监测数据,分析了连拱隧道在偏压条件下,围岩位移变形特性,讨论了偏压对连拱隧道稳定性的影响,对比分析了数值模拟值与隧道施工监测数据。研究结果表明:偏压连拱隧道施工过程中,左洞上台阶与中隔墙连接处及右洞拱腰处为相对薄弱位置,得出了连拱隧道结构受力特征,以期为类似工程设计和施工提供参考。

To study effects of the asymmetry during construction and the bias effect caused by natural terrain on the safety of double-arch tunnels under adverse geological conditions and rainy sections,this paper takes Leijiatai biased double-arch tunnel in central-western of Hunan Province as engineering background.Based on the seepage-stress coupling analysis theory,the excavation process of bias multi-arch tunnel is simulated by using the finite element analysis software MIDAS/GTS.Combined with the monitoring data during construction,the deformation characteristics of surrounding rocks in the double-arch tunnel subjected to biased pressure are analyzed,the influence of biased pressure on the stability of double-arch tunnel is further discussed.The results of numerical simulation and of monitoring during construction are analyzed and compared,which indicate that the connection between the upper left step of the left tunnel and the middle partition wall and the arch of the right hole are relatively weak positions during the construction process of bias double-arch tunnel.The mechanical characteristics of the double-arch tunnel structure are also obtained to provide a reference for the design and construction of analogous projects.