寒区隧道溶洞安全距离及衬砌冻胀影响规律研究

为了探究寒区溶洞的大小、远近对隧道结构安全的影响规律，依托寒区某高铁岩溶隧道建立三维有限元模型，通过不同工况的模拟得出溶洞距隧道安全距离临界值与溶洞隧道体积比成正比关系，并拟合出安全距离临界值随溶洞与隧道体积比的变化曲线和关系式。探究溶腔积水冻胀力对衬砌结构的影响规律，基于该寒区隧道周边不同位置、远近的溶洞对其影响进行模拟，研究结果表明:隧底处溶洞冻胀力影响最为显著，且距隧底超过10 m时，小型溶腔冻胀力对隧道的影响较小，衬砌变形值渐趋稳定。研究结果可为该寒区隧道溶洞处理提供依据，并为后续类似工程提供借鉴。

Research on safe distance of karst cave and influence laws of frost heave on lining for tunnels in cold region

In order to investigate the influence of the size and distance of karst caves on the structure safety of tunnel in the cold regions,a three-dimensional finite element model was established based on a karst tunnel of high-speed railway project in the cold regions.Through the simulation of different conditions,it showed that the critical value of safe distance from karst cave to tunnel was proportional to the volume ratio of karst cave to tunnel,and the variation curves and relationship formulas of the critical value of safe distance with the volume ratio of karst cave to tunnel were fitted and obtained.The influence laws of the frost heaving force by the water accumulated in the karst cavity on the lining structure were investigated,and the influence was simulated based on the karst caves at different locations and distances around the tunnel in the cold region.The results showed that the frost heaving force of karst cave below the tunnel had the greatest influence,and when the distance to the tunnel bottom exceeded 10 m,the frost heaving force of small karst cavity had less influence on the tunnel,and the deformation of lining tended to be stable gradually.The results can provide basis for the treatment of karst cave for the tunnels in this cold region,and provide reference for similar projects in the future.