Division of Frost Damage Grades and its Prevention Measures in Tunnel

Abstract

By analysing the cause of frost damages in tunnel, in this paper, the basic principle for prevent frost damage was puts forward. Based on the basic conditions for frost damage occurrence and the extent of frost damage, the grades of frost damage were divided. The prevention measures were made for different grades, corresponding to the concrete engineering application, the waterproof, drainage and insulation technologies were discussed integrally. The results show that, preventing frost damage in tunnel includes waterproof, drainage and anti-frost. Waterproof is the foundation, drainage is the core, and anti-frost is the key. The average temperature of the coldest month, the freezing depth, the occurrence and recharge of groundwater, and the infiltration situation of groundwater were chosen as the control indicators to divide the grades of frost damage into five degrees. In accordance with the different degrees of frost damage, the anti-freezing measures of using center gutter, deep center gutter, thermal-protective layer and drain cavern were proposed. The structure form which uses composite lining and set the waterproof layer between the linings, are not only benefit for waterproof and drainage, but also for anti-freezing. The hard polyurethane plank has good insulation performance and durability, it is an ideal material for anti-freezing and insulation in tunnel.