Experimental study on the damage mechanism of tunnel structure suffering from sulfate attack

The function of tunnels is degraded due to sulfate ambient, which has spread widely in Western China. The characteristics of tunnel concrete damage, development of cracks, structure deformation, and the safety factor of tunnel liner suffering from sulfate attack are studied in this work using field investigation and laboratory tests. The main damage styles of tunnel lining structure included structure cracking, spalling, leakage filtration, degradation, and corrosion. These indicate that either physical damage by crystal erosion or chemical dissolution damage - or both - may have occurred. They appeared in the liners with weak waterproof ability, poor compaction, and high hydraulic gradient. The crack of the tunnel liner first developed at the vault, and there were more cracks at the vault than in other places when the load was high. Crack width and structure deformation increased with load and erosion time as exponential functions, whereas the safety factor was reduced as a negative exponential function. (c) 2013 Elsevier Ltd. All rights reserved.