Classification, Causes of Tunnel Frost Damages in Cold Region and Several New Technologies to Prevent Them

摘要

This paper classifies the tunnel frost damages and discusses their causes, especially the causes of lining structural damage for freezing and they are classified into two categories: the outer freezing damage and the inner freezing damage of lining. The analysis shows that the former has a little effect on the structure, but the latter has big threat. For the phenomenon that cracks frequently occur in the tunnel lining of cold regions, some measures to prevent cracks are presented, including reducing adverse constraints in the process of temperature change and preventing large temperature stress. In cold regions, it is unsuitable to adopt back paste-type water-stops to prevent the leakage from lining construction joints, and a good choice is to utilize the buried drainage water-stops. The ring drainage pipes directly connect with the central drainage pipe, and thermal insulating layer with belt shape is set along the ring drainage pipes in some sections where surrounding rock is water-rich and the middle and lower part of the ring drainage pipe are easily frozen. In sections with high potential freezing threat, an anti-freezing plan is offered that electric heating wires are installed behind the lining wall. The test shows that above techniques have good effects in cold region tunnels.