Abstract:In order to explore the influence of karst cave on the deformation and stress characteristics of the tunnel structure, based on numerical simulation method, two-dimensional finite element model was established by changing the location, size and net distance of the tunnel,the displacement and internal force of the tunnel structure was analyzed. The results showed that the cave changed the deformation and stress of the tunnel structure. As the distance between the cave and the tunnel increases, the displacement of the tunnel structure gradually becomes smaller. Under the same clearance, the displacement of the tunnel structure increases with the increase of the size of the cave. Compared with the non-dissolved hole working conditions, the karst cave caused the internal force of the tunnel structure to be redistributed. The deformation and internal force of the tunnel structure on the side close to the karst cave were larger. When the diameter of the cave is less than 0.4 times the tunnel size, the influence of the cave on the deformation and internal force of the tunnel is weak. When the diameter of the cave was greater than 0.6 times the tunnel size and the tunnel distance was less than 0.3 times the tunnel size, the cave has a significant influence on the deformation and internal force of the tunnel structure, this area was a construction danger zone. Finally, through comparative analysis, it was concluded that the most unfavorable cave location for tunnel stability was the tunnel side cave. The research results can provide scientific reference and reference for the design and construction of karst tunnels.