Influences of Lining Stiffness Distribution on Frost Heave Pressure on Cold Regional Tunnels

To ensure that lining has a suitable safety degree,a constrained frost heave model was proposed based on the interaction characteristic of frozen water body,lining and surrounding rock,and the corresponding analytical expression of frost heave pressure was give.A load-structure model was adopted to analyze the distribution of lining stiffness.In addition,the relationship between frost heave pressure and lining stiffness was investigated by taking the structure safety degree as an assessment index.The research result shows that the stiffness distribution of lining with identical thickness is uneven-lining stiffness is small at the arch crown of a tunnel and middle part of its inverted arch,while it is large along its side walls.The increase in the thickness of lining will make lining stiffness raise to result in a great frost heave pressure and the load-bearing capacity of lining increase significantly.As a result,increasing the thickness of lining is still an effective measure to improve the anti-freeze ability of cold regional tunnels.