岩溶发育区电力管廊隧道稳定性分析与优化设计

Stability Analysis and Optimization Design of Power Pipe Gallery Tunnel in Karst Area

针对岩溶发育区城市电力管廊隧道的稳定性问题及线路设计方案问题,通过分析工程地质条件与岩溶发育特征探究岩溶对于隧道稳定性的影响,并结合有限元数值模拟对比分析隧道线路优化设计前后两种工况下的隧道底部竖向位移和塑性区的分布变化情况。结果显示,场区的岩溶对于隧道场地的地基稳定性有一定的不利影响,局部可能会出现应力集中现象,威胁到盾构施工及隧道运营的安全。数值模拟计算结果显示,将隧道线路上调增大隧道与溶洞的间距,可减少隧道底部竖向位移和围岩变形,溶洞顶部应力集中导致的剪切破坏较少。优化的隧道设计方案可以有效提高隧道稳定性和工程经济性,对类似工程有一定的参考价值。

In view of the stability problem and line design scheme of urban power pipe gallery tunnel in karst development area,the influence of karst on tunnel stability is explored by analyzing the engineering geological conditions and karst development characteristics.Combined with the finite element numerical simulation,the distribution changes of vertical displacement and plastic zone at the bottom of the tunnel under two conditions before and after the optimization design of tunnel line are compared and analyzed.The results show that the karst has a certain adverse effect on the foundation stability of the tunnel site,and the stress concentration may occur locally,which threatens the safety of shield construction and tunnel operation.The numerical simulation results show that the distance between tunnel and karst cave is increased by increasing the tunnel line,the vertical displacement at the bottom of tunnel and the deformation of surrounding rock are reduced,and the shear damage caused by stress concentration at the top of karst cave is less.The optimized tunnel design scheme can effectively improve the stability and engineering economy of the tunnel,which has certain reference value for similar projects.